Advice note

10 May 2007

GPDA STATEMENT ON METAL COMPONENTS
The GPDA wishes to draw attention to the risks involved when the components within a proprietary system of a GPDA member company are substituted for metal components supplied by others.

The use of metal components supplied by others will invalidate the warranty for the proprietary system where the GPDA member cannot substantiate the performance of untested components which are substituted and which may potentially reduce the performance of the proprietary system. In addition, where components supplied by others are used the GPDA member cannot confirm that the system will comply with their published performance claims.

The GPDA confirms that whilst the warranty for the proprietary system may be invalidated where other components are used, this will not affect the rights and remedies of customers where components fail and such failure is due to a defect in a component supplied by a GPDA member.

The Gypsum Products Development Association's (GPDA) members (British Gypsum, Gypsum Industries, Knauf Drywall, Lafarge Plasterboard) supply proprietary systems which are fully tested to offer substantiated performances complying with fire, thermal and acoustic standards. GPDA members provide all components for their proprietary systems and warrant these systems.

PRESS RELEASE

24 April 2007

CE MARKING OF PLASTERS FOR FIBROUS & GRG PLASTER
CE marking of plasters for fibrous & GRG plaster work EN 13815 enters into force on 01/06/2007 in the UK and Ireland from on 01/06/2007 with the co-existence period ends on 01/ 06/ 2008. CE marking of plasterboards, jointing materials, metal framing components and plasterboard products from reprocessing, commenced from 1st October 2006, while preformed plasterboard cornices, plasterboard composite panels and adhesives have been CE marked from 1st March 2007.

The CE mark is, of course, an EU mark. It guarantees that CE marked products manufactured by the UK and Ireland comply with the essential requirements stated in the BS EN and IS EN harmonised standards relevant to each product, and that the system of attestation of conformity laid down in the Commission Decision relating to the product has been applied. It is important to realise that the CE mark is not a mark of origin, nor - as it has sometimes been confused - is it a quality mark.

The technical specifications required by the EN are performance based, and our members have assessed and tested their products using the relevant evaluation method identified in the harmonised standard. The important performances of the products are declared in the information accompanying the CE marking and this marking also confirms that the threshold values of the performance specification have been met.

The responsibility for applying the CE marking lies with the manufacturer.

Except in the case of powders and small fixing components, CE marking will be on either the product or the packaging. The following information must be displayed: Name of producer and their registered address Last 2 digits of the year in which the marking is fixed, e.g. 06 the number of the European Standard and information on regulated characteristics.


European Standards – Applicable to Products Only

For UK and Ireland pre-fix BS or IS

Plasters EN 13279-1 Building Plasters
(BS1191 and eg. both undercoat and skim
IS 27)

EN 13815 Plasters for fibrous & GRG plaster work

PRESS RELEASE

30 March 2007

GYPSUM PRODUCERS HISTORIC RECYCLING COMMITTMENT
Plasterboard manufacturers in Great Britain have today signed up to a trailblazing agreement that is set to bring a significant reduction in the amount of waste plasterboard sent to landfill.

The voluntary agreement was initiated and brokered by the Gypsum Products Development Association (GPDA) which, in Great Britain, represents Knauf Drywall, British Gypsum and Lafarge Plasterboard.

The GPDA approached Defra last year with an outline proposal and has since been working with WRAP (Waste & Resources Action Programme) and the government-funded Market Transformation Programme to define the targets to which the industry will work.

Formalised within the Ashdown Agreement signed today, the targets are:

to reduce the amount of waste being sent to landfill from manufacturing operations in Great Britain to 10,000 tonnes/year by 2010; and
to increase the take back and recycling of plasterboard waste, for use in plasterboard manufacture, to 50% of new construction waste arisings by 2010.
In addition, all parties have agreed to work with other parts of the supply chain to develop processes to reduce the amount of wastage generated in new construction and to make further progress towards achieving the ultimate objective of zero plasterboard waste to landfill.

Ben Bradshaw, Minister of State for Local Environment for Defra, welcomed the agreement. He said:

“Reducing the waste we produce, reusing what we can, and recycling as much as possible of what’s left are all essential if we are to cut the amount of waste we send to landfill.

“This agreement represents an important step forward for the construction sector and it is particularly encouraging that it has been achieved on a voluntary basis. I hope the example it sets will be recognised by other parts of the industry and that sector-wide agreement can be secured.”

Ross Finnie, Minister for the Environment and Rural Development for the Scottish Executive, said:

“I welcome this agreement to reduce the amount of waste sent to landfill. This is in line with our Scottish Business Waste Framework which highlights the role voluntary agreements can play in sustainable waste management.”

Environment Minister for the Welsh Assembly, Carwyn Jones, welcomed the agreement. He said:

“It is essential that we recycle and reus

e as much as possible to reduce the amount of waste we send to landfill. “This agreement is a big step forward for the construction sector and I am particularly encouraged that it has been achieved on a voluntary basis. It is a great example to set for the construction industry as a whole, and I hope that it will lead to a further, sector-wide agreement in future.”

Crispin Dunn-Meynell of the GPDA explains:

“Much has already been achieved by plasterboard manufacturers and construction contractors in Great Britain, both in terms both of recycling manufacturing process waste and waste from construction sites. This new initiative sets tough but achievable targets for the future and, critically, has broad government support.

“We will now be working further with WRAP, the Market Transformation Programme and other parts of the drywall industry to develop similar agreements with distributors and contractors.”

Ian Wardle, Construction Programme Manager for Materials Recycling at WRAP, adds:

“The Ashdown Agreement is important not just because of the impact on waste reduction but because it is a voluntary initiative. Plasterboard is an increasingly popular product; approximately 2.5 million tonnes were used in construction in 2006, and some 300,000 tonnes of plasterboard waste was generated. It is essential that we find effective ways of reducing and recycling this waste.”

Advice Note

01 October 2006

CE MARKING OF WALLBOARD & RELATED PRODUCTS & ACCESSORIES
CE marking of plasterboards will commence in the UK and Ireland from 1st October 2006. CE marking of jointing materials, metal framing components and plasterboard products from reprocessing, will also start from 1st October 2006, while preformed plasterboard cornices, plasterboard composite panels and adhesives will be CE marked from 1st March 2007.

The CE mark is, of course, an EU mark. It guarantees that CE marked products manufactured by the UK and Ireland comply with the essential requirements stated in the BS EN and IS EN harmonised standards relevant to each product, and that the system of attestation of conformity laid down in the Commission Decision relating to the product has been applied. It is important to realise that the CE mark is not a mark of origin, nor - as it has sometimes been confused - is it a quality mark.

The technical specifications required by the EN are performance based, and our members have assessed and tested their products using the relevant evaluation method identified in the harmonised standard. The important performances of the products are declared in the information accompanying the CE marking and this marking also confirms that the threshold values of the performance specification have been met.

The responsibility for applying the CE marking lies with the manufacturer.

Except in the case of powders and small fixing components, CE marking will be on either the product or the packaging. The following information must be displayed: Name of producer and their registered address Last 2 digits of the year in which the marking is fixed, e.g. 06 (In the case of plasterboard) The type and thickness of the board & the number of the European Standard. And information on regulated characteristics

The relevant standards for plasterboard are BS EN 520 and IS EN 520 which replaces the British BS and Irish IS standards. When CE marking commences, all references to previous BS and IS standards will cease to be shown on the product and labelling.

Types of Gypsum Plasterboards (Extract from EN 520)

3.2.1 General

The performance of the types of gypsum plasterboards defined below may be combined in one board in which case the letter identifying each type of performance satisfied shall be given in the designation.

3.2.2
gypsum plasterboard Type A
(BS1230 Type 1)
Plasterboard with a face to which suitable gypsum plasters or decoration may be applied.

3.2.3
gypsum plasterboard Type H (plasterboard with reduced water absorption rate)
(BS 1230 type 3)
Types of boards which have additives to reduce the water absorption rate. They may be suitable for special applications in which reduced water absorption properties are required to improve the performance of the board. (only H1 in UK and Ireland)

3.2.4
gypsum plasterboard Type E (gypsum sheathing board)
(BS1230 N/A)
Boards specially manufactured to be used as sheathing board in external walls. Not available in the UK, as yet.

3.2.5
gypsum plasterboard Type F (gypsum plasterboard with improved core adhesion at high temperature)
(BS1230 type 5)
Plasterboard with a face to which suitable gypsum plasters or decoration may be applied. These boards have mineral fibers and/or other additives in the gypsum core to improve core cohesion at high temperatures.

3.2.6
gypsum plasterboard Type P (gypsum baseboard)
(BS1230 type 6)
Boards which have a face intended to receive gypsum plaster.

3.2.7
gypsum plasterboard Type D (gypsum plasterboard with controlled density)
(BS1230 N/A)
These boards have a controlled density with a face to which suitable gypsum plasters or decoration may be applied. eg. Sound resistant wallboards

3.2.8
gypsum plasterboard Type R (gypsum plasterboard with enhanced strength)
(BS1230 N/A)
These boards are for special applications where higher strength is required have both increased longitudinal and transverse breaking loads.

3.2.9
gypsum plasterboard Type l (gypsum plasterboard with enhanced surface hardness)
(BS1230 N/A)
These boards are used for applications where higher surface hardness is required.



European Standards – Applicable to Products Only

For UK and Ireland pre-fix BS or IS

Boards EN 520 Gypsum plasterboards (all board types)
(BS1230 part 1 IS 41)

Ancillary Products EN 13963 Jointing materials for gypsum plasterboard
(No BS) eg. Powder and Readymix.

EN 14195 Metal Framing Components for gypsum boards
(BS7364 eg. All studs and channels
studs and channels
only)

EN 14209 Preformed plasterboard cornices
(No BS) eg. Cove

EN 14190 Plasterboards – Products for reprocessing
(No BS) eg. foil backed boards

Composite EN 13950 Gypsum plasterboard composite panels
(No BS) eg. thermal board laminates

EN 14496 Gypsum Based Adhesives for composite boards
(No BS) eg. Bonding Compound

Plasters EN 13279-1 Building Plasters
(BS1191 and eg. both undercoat and skim
IS 27)

PRESS RELEASE

04 September 2006

UK DECLARES FGD GYPSUM A PRODUCT
The UK Government's Environment Agency have classified FGD gypsum as a by-product in advance of the outcome from the consultation on by-products by the European Commission as part of the wider review of the European Waste Framework Directive.

This decision came after strong representation from the UK gypsum association, the GPDA, and the electricity producers association, the AEP, after the Environment Agency had initially classified FGD gypsum as a waste, which would have had serious licensing, handling and storage implications for gypsum product manufacturers.

The UK gypsum producers welcomed the decision as a return to common sense in encouraging the use of a sustainable product, which reduces the need for gypsum mining for the foreseeable future. It is to be hoped that this creates a precedent for the classification of FGD gypsum in other European countries.

PRESS RELEASE

24 February 2006

SOUND UPGRADES PROVIDE ADDED VALUE OPPORTUNITY FOR BATHROOM SPECIALISTS
Upgrading sound performance in bathrooms can make a major contribution to the quality of the home environment, yet is often overlooked during bathroom refurbishments. It’s a task which, believes the Gypsum Products Development Association, could offer an additional business opportunity for bathroom specialists and increase the sales appeal of the service offered by them.

GPDA represents the UK's plasterboard systems manufacturers, whose products are integral to most properties built in recent years and can also be used to enhance the performance of traditional brick and block built properties.

Depending on the design and age of a property the level of sound proofing within bathroom walls may be in line with current Building Regulations or fall well short of today’s standards. Few people want to upgrade partition performance in isolation since it demands an element of disruption and re-decoration. However, when bathrooms are re-fitted there is considerable attendant disruption and existing wall finishes are commonly damaged as a result of the removal of tiles and fittings. The additional work and inconvenience associated with sound upgrades at this time is, therefore, minimal. Neither is the cost great, since materials are likely to cost less than £50 for a typical partition wall.”

Removing an original plasterboard lining to insert acoustic insulation into a partition cavity and replacing it with a higher performance board is a simple and quick process which, in many instances, may be easier than making good an existing lining prior to re-decoration. Similarly adding a layer of plasterboard on top of an existing masonry wall is quick and simple and brings enhanced sound performance.

Current Building Regulations (England & Wales) call for new homes to be built with 40 decibel (dB) sound attenuation between bathrooms and adjoining rooms. From the mid 1980s to 2003 it was common to build-in 38 dB performance to meet the guidelines set by the NHBC. Older properties may not necessarily achieve these levels, resulting in rather more being heard from the bathroom than might be acceptable. The greater the thickness of board, the greater the acoustic performance.

Moisture resistant board products should be used in bathroom applications.

Adding a 12.5mm board on top of the existing facing, or blockwork, should increase sound attention performance by 3 decibels. Adding two layers of 12.5mm board will give a proportionate increase of 6 dB. Boards can be fixed to masonry using special bonding compounds or with the aid of metal brackets which, if required, can be set so as to create a cavity to accommodate services.

Where the facings of studwork partitions retain their integrity after removal of tiles, additional boards can be fixed to them using special adhesives, as with blockwork. Alternatively, if the condition of the existing board indicates it is better to remove the original material, the new facing can be fixed to the studs using drywall nails (in the case of timber) or screws (for timber or metal studs). Adding a 25mm thick ‘acoustic partition mat’ (a special type of insulation) in the cavity makes a further improvement of around 5 dB.

Standard tiles can be fixed directly to drywall facings using tiling adhesive, following application of a suitable PVA bonding coat. Alternatively the boards can be decorated using a water resistant emulsion, or skim plastered, again after application of a suitable bonding agent.

Whilst drywall installation may not necessarily be part of the bathroom specialist’s skill set, applications of this type are generally straightforward. Short training courses offered by all the main plasterboard manufacturers would enable most to acquire the necessary expertise in a matter of days.

Says Crispin Dunn-Meynell: “There is little doubt that combining a stunning new bathroom with enhanced sound performance will add to customer satisfaction and can offer an additional profit opportunity for the bathroom specialist.”

GPDA STANDARDS UPDATE

30 November 2005

APPLICATION, PLASTERS EN 13914-2:2005
EN 13914-2:2005, ‘Design, Preparation And Application Of External Rendering And Internal Plastering – Part 2:Design Considerations And Essential Principles For Internal Plastering’ was published in June 2005. This standard gives the design considerations and essential principles for internal plastering systems and application of plastering systems. The standard gives in different parts:
- Requirements and recommendations for building details
- Design and materials considerations
- Selection of mixes and the application of gypsum plasters
(Plasters, Gypsum plaster, Anhydrite, Sulfate minerals, Cements, Lime, Plastering, Construction operations, Surface treatment, Inspection, Test methods, Render, Wall coverings, Construction systems parts, Walls, Coatings, Coating processes, Finishes, Wall coatings, Exterior wall coverings, Construction materials, Design)

Equivalent national standards were withdrawn as at 30/11/2005.

PRESS RELEASE

29 December 2005

SURVEY REVEALS HOMEOWNERS WILL PAY MORE FOR BETTER SOUND PROOFING
A new survey has revealed that many homeowners are worried by the level of intrusive noise in their properties. The TNS Omnibus survey, undertaken on behalf of the Gypsum Products Development Association, indicates that around one fifth of all homeowners experience problems with noise transference, rising to nearer a quarter amongst owners with properties under 30 years old.

Some 85 per cent of owners feel better sound proofing would have a positive effect on house value with the average figure quoted being an increase of £2,500. Survey respondents thought it would cost a builder just over £2,000 to install higher specification sound proofing at build stage. In fact very significant enhancements, over and above the standards required by Building Regulations, can be made using drywall systems for about £500 on a typical new three bedroom home.

Not surprisingly, living rooms (62 per cent) and bedrooms (57 per cent) were identified as the main rooms in which intrusive noise was seen as a problem. This remains the case irrespective of property age.

Overall, noise generated inside the home was seen as the main cause (37 per cent) with noise from neighbouring properties slightly lower at 34 per cent. General background noise was mentioned as a nuisance only by 29 per cent of respondents. Interestingly, the percentage of those mentioning intrusive noise between rooms inside a property is higher for those with properties under 30 years old, whilst the figure for noise from neighbouring properties is lower. The greatest problem with noise from neighbours appears to be in homes which are over 60 years old.

More people find noise transference a problem on the first floor of their homes than on the ground floor. Results indicate that unwanted noise has affected satisfaction levels for two thirds of people who have experienced it, although it is a major concern only for 7 per cent. Noise appears to have affected property satisfaction levels less for owners of properties less than 30 years old than for those with older homes. However, overall the survey indicates one in five homes experiences problems with noise – equating to around 4.5 million properties in the UK.

With sound performance an important issue in any domestic property, and homeowners seeking ever better quality standards, this latest survey clearly demonstrates that homeowners are willing to pay a premium for higher standards. Today’s plasterboard systems provide the ideal solution offering quick and easy installation, excellent sound performance and a quality finish.

Notes:
The survey was conducted by RSGB Omnibus, a division of TNS. TNS is one of the world’s leading market information groups, providing market measurement, analysis and insight through its global network of operating companies in 70 countries.

GPDA ADVICE NOTE

07 November 2005

SAFE HANDLING PLASTERBOARD GUIDELINES
Plasterboard is marketed for use in the Drylining of domestic, commercial and retail buildings. It is important that such products are used only in the manner for which they are intended and in accordance with manufacturer’s instructions. Good working practice will help to eliminate potential hazards.

If handling plasterboard sheets manually, consider risks as required by manual handling operations regulations 1992. Care should be taken at all times to avoid strain to the handlers; heavy products should only be lifted in the correct way. Be aware that the size of boards can restrict field of vision. If any of these are an issue, or where access is restricted, consider using narrower boards, eg. 900mm wide.

A range of mechanical handling equipment is also available. Plasterboard handling trolleys and hoists are obtainable and some of these will allow integration with the delivery of plasterboard to site.

In all cases, good sense should prevail. Workers differ in size and strength and should not be permitted to attempt manual work which may be beyond their capability.

GPDA PRESS RELEASE

27 October 2005

INVEST IN DRYWALL SYSTEMS FOR A QUIETER HOME
Modern Building Regulations require all new homes to be built to markedly higher standards of sound performance than was the case some years ago. Notable ‘milestones’ along the way have been the introduction of a requirement for properties covered by the National House Builders Confederation (NHBC) to achieve 38 dB sound separation between bathrooms and bedrooms – so you can’t hear so much of what goes on in the loo – and, more recently, the latest amendments to Building Regulations Part E (England & Wales), which deals with sound and requires partitions to achieve 40 dB sound separation. At the 40 dB level you can’t make out what people are saying in an adjacent room but you may still be aware of them talking. Taking performance a step better still, up to 45 dB, is not difficult and takes away even the background ‘mumble’.

Sound enters and moves around a property by a variety of means. Noise from the outside may pass through party walls, exterior walls, the roof, windows and doors. Sound inside a home passes from room to room through the partitions, walls and floors/ceilings.

Current regulations (England & Wales) require party walls to achieve the equivalent of 55 dB, whilst internal partitions must achieve 40dB. The same applies to sound performance between storeys and through the roof.

Windows, normally now double glazed, provide about 38dB performance. There are no sound performance regulations relating to external or internal doors, although an external door made of plastic and with glazed sections will typically offer 30-35dB performance. Internal doors typically only have a thin facing over a cardboard interior – making them lightweight but reducing sound performance.

Improving sound performance over that required by the Building Regulations can help to provide a quieter living environment still – helping to guard against unwanted noise from the exterior and provide greater privacy between internal rooms.

A significant further improvement in partition performance can be achieved in one of three ways using drywall systems.

Adding an extra layer of board on either side of a partition will boost performance by around 6dB (3dB for each side).

If there is no insulation between the drywall faces of a partition, adding it will boost performance by 5dB.

Incorporating resilient bar on one side of the wall can offer a 7dB improvement because this type of fixing effectively isolates the facing board from the studwork, making it harder for sound to travel through the partition.

Using a ‘standard’ metal stud rather than a timber stud adds 3dB and specification of high performance acoustic metal studs adds a further 2-3dB to performance.

Of course, in a completed property such measures are ‘easier said than done’ – but upgrades as part of other projects, a major kitchen or bathroom upgrade or re-modelling of room layouts is well worth considering if unwanted noise is proving a problem. Remember, of course, that adding to wall thickness also means widening door surrounds.

Self-builders embarking on new construction projects can readily incorporate the higher standards indicated above – at little additional cost, relative to the overall price of construction.

When purchasing a new home asking for such upgrades may be a possibility when buying off plan, although this will undoubtedly vary from builder to builder.

GPDA PRESS RELEASE

20 October 2005

KEEPING SOUND AT BAY – DRYWALL PROVIDES THE ANSWER
Controlling unwanted noise is a growing concern for house purchasers, reflected in recent changes in the Building Regulations. It is, perhaps, natural to think that the best sound performance can come only from using traditional brick and block construction. This perception undoubtedly dates back to the early days of plasterboard when partitions typically were built using relatively thin boards and without insulation. Today, the situation is very different and drywall can be used to meet the most demanding sound specifications.

It is for this reason, among others, that drywall is becoming the preferred choice for most housebuilders and for the growing number of self-builders, who today account for a substantial proportion of the new houses constructed each year in the UK.

To put performance, and developments, into context it is useful to understand the level at which sound typically becomes intrusive. Sound is measured in decibels (dB). A partition (be it a wall, floor or ceiling) that offers 40 dB of sound attenuation will make it impossible to interpret normal speech through the partition, although a low frequency ‘mumble’ may still just be audible. Above about 45 dB that low frequency mumble will also disappear. Sound insulation levels at the local multiplex cinema need to be around 70 dB to stop output from high powered sound systems passing from one auditorium to another.

There are two forms of sound, ‘airborne’ sound – the person talking next door, and ‘impact’ sound – someone walking on the floor above.

Most of the homes built in the 10 years following the end of the Second World War were constructed using traditional bricks and blocks. Early ‘breeze blocks’ achieved around 40dB airborne sound insulation.

In the 1960s the breeze block was largely replaced by lightweight aerated concrete blocks. These have the advantage of offering good thermal performance and are quick to lay. Their sound attenuation is about 35 dB.

At a similar period it became common practice to construct non-loadbearing internal partitions using plasterboard and a popular approach was to install a type of pre-formed partition with a 9.5mm layer of plasterboard on either side of a cardboard ‘honeycomb’ section between the two facings. This type of partition was lightweight and quick to install but sacrificed sound performance in favour of offering a slim construction just 57mm thick – nearly half that of a plastered breeze block wall – giving more usable floor space in the property. (These partitions are no longer manufactured in the UK).

Today’s drywall systems combine the best of both worlds, achieving slim profiles whilst also offering high standards of sound insulation that equal and often better those provided by solid masonry construction.

Explains Chris Walker chairman of the technical committee at the Gypsum Products Development Association, which represents producers of drywall systems: “The performance of drywall systems in respect of sound is linked to the way the partition is constructed. A solid masonry partition has no ‘sound break’ so, despite its mass, some airborne sound can still travel through it and impact sound conducts across it. Drywall systems are constructed by placing boards on either side of the metal or timber studs which support them, so there is a gap between one side and the other. The cavity hinders the passage of both airborne and impact sound and so contributes to performance.” This can be further increased by the use of sound absorbing mineral wool in the cavity.

A typical drywall partition wall in a house constructed today will be 75mm thick, including the wall finish and will readily achieve 40 dB sound performance, even without any insulation in the cavity. This compares with a solid block partition which will typically achieve the same sound insulation but be 100mm thick.

At the same time as offering good sound performance and keeping partitions slim, drywall is lightweight. This means the position of partitions on upper storeys does not need to be the same as that on the ground floor – giving considerable versatility in floor structure and plan design. And that’s why your home today is a little bigger inside than it could have been in the past, quieter to live in and why housebuilders time and again use today’s advanced drywall systems for internal walls. For interest, it is also why drywall systems, to higher specification designs, are routinely specified for multiplex cinema applications.

GPDA PRESS RELEASE

25 May 2005

GYPSUM ACHIEVES ENERGY SAVING TARGET
The GPDA submission to DEFRA for its first and second two year milestones showed that the Gypsum Sector exceeded its energy reduction target. All the UK manufacturers in the climate change agreement met their targets, after allowable adjustments for product mix and emissions trading.

The gypsum industry remains committed to the spirit of the Kyoto agreement and the UK’s Government’s efforts to reduce CO2 emissions. The UK gypsum manufacturers continue to improve process efficiencies, through constant technological development driven by the individual companies and careful management, despite already having one of the most technically advanced and energy efficient manufacturing processes.

We support efforts by the CBI and CPA to persuade the Secretary of State to allow all companies the opportunity to commit to climate change agreements. Gypsum illustrates the unfairness of the current system which does not allow smaller sites, using identical processes to produce identical products, to join the agreement and benefit from an 80% rebate on the climate change tax in exchange for challenging energy targets, putting them at a commercial disadvantage.

GPDA Advice note

25 October 2005

CREAKING NOISES FROM CEILINGS
A small number of householders have complained about a 'creaking' or 'cracking' sound coming from first floor ceilings in their new properties, when individuals walk on the floor above. After investigation, it has been established that the plasterboard ceiling is not to blame.

The joists (mostly fabricated I joists) are the flooring structural elements and should be designed/adequately braced to prevent excessive movement. If they are not, then other elements within the floor structure including the plasterboard ceiling may creak due to the floor flexing under load.

There is a cost to strengthening the flooring in order to put this right. Plasterboard is not to blame, so plasterboard manufacturers would not be liable for the cost.

The only way to be sure of solving the problem is to strengthen the floor to reduce the excessive movement. However a potential remedial treatment is to decouple the ceiling boards from the joists using a metal ceiling system such as resilient bars.

For further information and advice on this issue, please contact:-

UK Timber Frame Association
The e-Centre
Cooperage Way Business Village
Alloa
FK10 3LP

Email office@timber-frame.org
Telephone 01259 272140

With all ceilings, we recommend that plasterboard is screwed rather than nailed into place, to minimise any movement, which could eventually result in nail popping.

GPDA Advice Note

19 July 2005

DISPOSAL OF GYPSUM PRODUCTS WASTE
The European Directive on the Landfilling of Waste is reducing the UK's reliance on landfill and is helping to ensure that wastes destined for landfill are treated to reduce their environmental impact. The Directive was approved in 1999 and the implementation of the requirements has taken place progressively since 2001. Corresponding national legislation has resulted in a phased introduction of its requirements by the waste industry.

The GPDA wishes to clarify the position with regard to plasterboard and plaster waste following the important change in legislation which became effective on the 16 July 2005.

Gypsum products such as plasterboard and plasters have a sulphate content much higher than 10%. From 16 July 2005 they will be required to be disposed of in mono-cell landfill facilities for 'high sulphate wastes'. They will continue to be classified as 'Non-hazardous' in most circumstances.

However from 16 July 2005 high sulphate bearing materials can only be accepted in non hazardous landfills if they are kept separate from biodegradable waste. Small amounts of gypsum waste will also still be acceptable in a mixed load (e.g. less than 10% plasterboard in a load). Therefore if you produce waste that includes a large percentage of sulphate waste you need to consider now, how you will manage your waste from this July.

The European Waste Catalogue Classification Code for plasterboard and plaster wastes resulting from construction or demolition is normally 17 08 02. (note: if the product has become contaminated with 'dangerous substances' then the code would be 17 08 01* - i.e. it would then require disposal as hazardous waste ).

Prevention is naturally the preferred solution. Designers and contractors can play a significant part in avoiding the unnecessary generation of waste. Designing out waste by the correct selection of the most suitable size of plasterboard together with good site management waste are key elements in reducing waste.

Your waste management services provider will be able to advise you of suitable solutions for the disposal of waste. Further guidance is available from member companies of the GPDA and also from the Environment Agency (see http://www.environment-agency.gov.uk/commondata/acrobat/gypsum3_1122535.pdf ).


British Gypsum Tel: 01159 451000
www.british-gypsum.bpb.co.uk
Lafarge Plasterboard Tel: 01275 377773
www.lafargeplasterboard.co.uk
Knauf Drywall Tel: 01795 424499
www.knaufdrywall.co.uk
Environment Agency Tel: 0845 933 3111
www.environment-agency.gov.uk

PRESS RELEASE

16 September 2004

FIRE TESTS – THE EUROPEAN STANDARD
As a result of efforts to harmonise fire test standards throughout the European Union, British standard fire resistance and reaction to fire tests will gradually be replaced by harmonized European Standards.

It is anticipated that the existing British Standard BS476 will continue to be used for the time-being, as there is currently no target for legislation to require the testing of products to the EN standard, EN1363 and plasterboard manufacturers will continue to quote the BS in their technical literature. Gradually, however, specifiers will become familiar with the EN standard and the BS will become less used, and will eventually become obsolete.

It is anticipated that gypsum wallboard manufacturers in Great Britain and Ireland will quote only EN fire test data in their literature from 1st January 2007.

PRESS RELEASE

14 September 2004

THE FUTURE OF 9.5MM WALLBOARD
In a World of greater environmental awareness, has 9.5mm plasterboard got a future? In the short term the answer is, undoubtedly, yes. It is the traditional choice, as the cheapest suitable board for a range of domestic and commercial situations. And where sound resistance and fire resistance are not an issue, or are not covered by specific regulation, it will continue to be widely used.

However, its days as the plasterboard of choice seem likely to be numbered, as the long term consumer demand for higher levels of sound resistance, and changing building types, are likely to may drive up board weights. Its lack of fire resistance, when tested in accordance with the more strict 1999 European test methods BS EN 1363 , 64 ,65 means that 9.5mm cannot achieve 30 minutes fire insulation and integrity in these tests. The superior strength and better spanning properties of the thicker boards are also important reasons for the eventual demise of 9.5mm.

In England and Wales the authorities have moved to strengthen the Building Regulations for sound insulation. Robust Details, constructions which avoid the need for further testing under the revised Building Regulations Part E Acoustic, do not allow 9.5mm wallboard, effectively slashing usage of 9.5mm board overnight, and there is an aspiration to also extend Robust Details to Part L Thermal.

There is not the same regulatory pressure in the Irish Republic, Northern Ireland or Scotland, which have not adopted Robust Solutions, but I those markets performance demands are also rising.

In the short term 9.5mm board does have a future and will remain widely available, but sooner or later its days as a mainstay of construction are now probably numbered.

GPDA ADVICE NOTE

12 September 2004

GPDA RECOMMENDED TECHNICAL SOLUTIONS
The following manufacturers; British Gypsum, Gypsum Industries, Knauf Drywall and Lafarge Plasterboard, representing all the gypsum product manufacturers in the United Kingdom and the Republic of Ireland, are in agreement with the following technical solutions:

The application of single coat finishing plaster is now only recommended to the front or ivory face of plasterboard. The application of single coat finishing plaster is not recommended to the back or grey side (the side where board markings have been applied - this side also has a paper joint). This applies to all grades of plasterboard (with the exception of moisture resistant grade) and whether the board has a tapered or square edge. Joints between adjacent sheets of plasterboard must be reinforced with joint tape bedded onto a gypsum based filler, in accordance with the plasterboard manufacturer’s recommendations. Where moisture resistant grade plasterboard is used the front face can be used to receive plaster, however, the surface must be pre-treated with a proprietary bonding aid. If a bonding or an undercoat plaster is to be applied to plasterboard, the plasterboard manufacturer should be consulted.

In addition to the above the manufacturers have also stated their preferred recommendation for fixing plasterboard to timber. To help avoid the phenomenon of nail popping, due to timber movement and shrinkage, the manufacturers recommend, in all cases where plasterboard is fixed back to timber, drywall screws are used in preference to nailing.

GPDA ADVICE NOTE

09 July 2004

APPROVED DOCUMENT E AND RDs
New Approved Document E of the Building Regulations (England and Wales) dealing with resistance to the passage of sound came into effect in July 2003 and introduced higher requirements for acoustic performance for residential building. The approved document is one of a series published by The Office of the Deputy prime Minister (ODPM) to provide practical guidance on meeting the requirements of Schedule 1 and Regulations 7 of the Building Regulations.

Approved Document E gives guidance with suggested constructions on how to provide reasonable levels of sound insulation between and within dwellings and other residential buildings (eg. hotels, hostels and buildings providing residential care). However these guidance constructions do not guarantee compliance and it was proposed that a sample of properties (1 in 10 on any site) would have to undergo Pre-Completion Testing (PCT) prior to final completion and occupancy. This applied to all residential properties other than new homes from 1 July 2003. For new homes and flats the requirements for Pre-Completion Testing came into force on 1 July 2004.

The House Builders Federation recognised that Pre-Completion Testing would be a costly burden on housebuilders and unnecessary where a proven acoustic solution guaranteed performance. Working with ODPM and building material producers, they have developed a set of practical Robust Details (RDs), for of construction which have been rigorously site tested to ensure that they demonstrate superior performance which significantly exceed the new Part E requirements. Approved Document E allows the use of Robust Details as an alternative to conducting pre-completion testing.

These constructions form the first pattern book of solutions published by RD Limited. The pattern book includes site checklists for each construction and detailed flanking junction details that are integral to the correct installation of these forms of construction.

In order to use RDs the developer must register their site with RD Limited and must pay a plot registration fee. Details regarding plot registration and an order form for the pattern book can be found on the Website www.robustdetails.com

A leaflet giving more details ‘Approved Document E: Robust Details and PCT’ can be downloaded from the Technical Literature page on this Website.

GPDA ADVICE NOTE

28 April 2003

BUILDING REGULATIONS PART E (ENGLAND AND WALES)
PROPOSALS FOR AMENDING THE PROVISIONS FOR SOUND INSULATION

1. INTRODUCTION
New Approved Document Part E of the Building Regulations dealing with resistance to the passage of sound was published in December 2002 with implementation as from 1 July 2003.
The Document is one of a series published by The Office of the Deputy Prime Minister (ODPM) to provide practical guidance on meeting the requirements of Schedule 1 and Regulation 7 of the Building Regulations. Part E gives guidance with suggested constructions on how to provide reasonable levels of sound insulation between and within dwellings and other residential buildings (e.g. hotels and buildings providing residential care).
However these guidance constructions do not guarantee compliance as it is also proposed that a sample of properties (1 in 10 on any site) will have their separating walls and floors tested prior to final completion and occupancy. This will apply to all residential properties (buildings where people sleep) other than new homes as from 1 July 2003. For new homes the same requirement is deferred from implementation until 1 January 2004. This is to allow the industry lead by The House Builders Federation (HBF) to develop a series of Robust Standard Details (RSDs) that will have been site tested to demonstrate superior performance to that required by Part E and thereby gain special dispensation from the need to pre-completion test. HBF expect these details to be released in May.


2. BACKGROUND TO CHANGE
Noise can be defined as sound that is undesirable. However, the point at which noise becomes obtrusive is very subjective and depends upon individuals’ tolerance. When a noise is troublesome it can reduce comfort in the home and if a person is subjected to it for long periods, it can result in physical discomfort or mental distress.
The effects of noisy neighbours can be one of the main problems experienced by occupants of attached homes. New planning guidelines (PPG3) requires a greater density of build on housing sites driving the industry towards a higher proportion of attached homes (link attached and apartments) in order to meet the more stringent guidelines. Therefore more homes will be affected by the needs for better standards of sound insulation between one home and another.

It has been estimated that about 4 million people in Britain are having their lives disturbed by noisy neighbours, sometimes with tragic consequences. The Chartered Institute of Environmental Health reports that the number of complaints about domestic noise has now reached over 5,000 per million of population and that the total number of such complaints has trebled. The 1996 English House Condition Survey indicates that nearly one quarter of households was bothered by noise either from traffic, industry or neighbours. A BRE study indicates that about 25% of occupants living in dwellings that attained the current standards for sound insulation rated the insulation as ‘poor’ or ‘very poor’. It is estimated that in new dwellings, as many as 40% of separating floors and up to 25% of separating walls may fail to meet the current standards.

The best defence against noise must be to ensure that proper precautions are taken at the design stage and during construction of the building. This means that the correct acoustic environment should be provided in each space and that noise transmission levels are compatible with usage.
Remedial measures can be expensive and inconvenient particularly after the building has been occupied. Ideally, the sound insulation requirements of the building should take into account both internal and external sound transmission.

3. KEY REQUIREMENTS
Mean sound reduction values for separating walls and floors will be lower than previously. However the airborne values will have a Ctr (co-efficient of traffic noise) factor (DnTw + Ctr – site test result) that is influenced by the reduction of low frequency noise such as base sound. These new values will be more difficult to achieve for many types of construction. Impact values will be measured as before, LnTw – site test result.

Approved Document E sets performance levels for the following areas of a dwelling or residential building – a comparison is also made with current standards:

Element of construction	Min Airborne sound transmission (site test result)		Max Impact sound transmission (site test result)		Min Airborne sound transmission (Lab test result)
	Old	New	Old	New	Old	New
	DnTw	DnTw+ Ctr	LnTw	LnTw	Rw	Rw
Separating walls between dwellings	49dB	45dB
Separating walls between rooms used for residential purposes	NR$	43dB
Separating walls between rooms created by a change of use (conversions)	49dB	43dB **
Separating floors between dwellings	48dB	45dB	65dB	62dB
Separating floors between rooms used for residential purposes	NR$	45dB	NR$	62dB
Separating floors between rooms created by a change of use (conversions)	48dB	43dB **	65dB	64dB **
An internal wall or floor between a bathroom/WC and a habitable room also between bedrooms and between bedrooms and any other room within the dwelling					NR$	40dB*

* Internal walls, which include a door, are exempt from this requirement
$ NR – No Requirement
** There is a ‘test and declare’ provision in Part E that may allow for a lower performance to be acceptable to Building Control for certain examples of existing construction

OTHER REQUIREMENTS:

 For entrance halls, corridors or hallways of communal areas in flats, an area equal to or greater than the floor area must be covered with a Class C absorber (or better)

 For stairwells or a stair enclosure of communal areas in flats, an area equal to the surface area of the stair and landings must be covered using a Class D absorber. Alternatively, 50% of the area must be covered using a Class C absorber (or better)

PRE-COMPLETION TESTING (PCT)

Previous site testing and research has shown that separating walls and floors capable of providing satisfactory levels of sound insulation in practice did not. New Part E will introduce the concept of pre-completion testing to ensure that designed performance is achieved in practice. Building Regulation AA and Approved Inspector Regulation BB give Building Control authorities the power to require pe-completion testing of separating walls and floors as a means of demonstrating compliance with the performance criteria for sound insulation given in Approved Document E. Building Control should request tests be carried out on a sample size of 10% of dwellings on a development or rooms on a residential or hotel project to check compliance with requirement E1 only in addition to their normal site inspections. Test work is normally carried out at the developer’s expense but where and what to test is to be as directed by Building Control. It remains the developer’s responsibility to meet the requirements of Part E for the entire site, not just the ones that are tested.

PCT should be carried out on dwellings created by a material change of use and rooms for residential purpose - whether purpose built or formed by material change of use as from 1 July 2003. PCT on new purpose built dwellings will be required as from 1 January 2004. This is unless Robust Standard Details (RSDs) are developed by industry to persuade the Authorities that the sound insulation provided by the RSDs has been shown to provide satisfactory performance consistently above the base criteria given in Approved Document E without the need to test prior to occupancy. Tests should be carried out when rooms either side of the separating element are completed prior to decoration but without the inclusion of any soft furnishings. Tests are not required on internal walls and floors or between living spaces and corridors.

4. GOOD DESIGN PRACTICE
Building acoustics is the science of controlling noise in buildings, including the minimisation of noise transmission from one space to another and the control of noise levels and characteristics within the space.

BUILDING LAYOUT – HOUSES/FLATS
When designing dwellings it is important to arrange the living areas to avoid incompatibility of use. Bedrooms should be sited away from the regularly occupied and usually more noisy areas (e.g. the living room) of the adjoining property. Additional sound insulation can be achieved if the common areas of walls and floors between rooms are reduced. The introduction of steps and staggers between properties not only adds another dimension to the general design layout but also reduces the common areas of contact and thereby improves the likelihood of better standards of sound insulation.
Bedrooms of one flat should be sited directly below the bedroom of the flat above and away from access balconies. Vertical ducts, refuse chutes and lifts should not adjoin bedrooms or living rooms. Boiler rooms or common circulation areas should be isolated from living spaces.
The positioning of bedrooms next to toilets or bathrooms should be avoided where possible except where en-suite facilities are an integral part of the design.

Passageways or built in wardrobes strategically placed can act as an ‘acoustic buffer’ in areas where higher sound insulation is desirable. Specific areas and the domestic appliances located in them that generate higher and repetitive levels of noise should be sited away from sensitive areas requiring quiet – e.g. bedrooms and rooms for study.
Studies by Liverpool University have indicated that significant improvement in reducing the transmission of low frequency sound can be achieved by ensuring that rooms adjacent to the common separating walls are mismatched in size.

BUILDING LAYOUT – HOTELS, NURSING HOMES AND STUDENT ACCOMODATION
When designing hotels and other multi-occupancy residential buildings, it is important to pay particular attention to the location and specification of doors into common spaces or corridors. The use of sound lobbies within the room or strategically positioned doors within the corridor can help control this transmission path. It is beneficial to design the room layout to maximise the distance between adjacent doors.

FLANKING SOUND TRANSMISSION
Flanking sound is transmitted indirectly via paths such as windows, external walls and internal corridors. It is defined as sound from a source room but not via a common building element. It is imperative that flanking transmission is considered at the design stage and that the construction detailing specified will eliminate or at least minimise any downgrading of the acoustic performance.

New Part E recognises that the practicalities of construction will mean that acoustic performances measured in the laboratory will be more difficult to achieve on site. One of the main reasons being loss of acoustic performance via flanking transmission through the surrounding structure.
Good detailing at the design stage will minimise this effect and optimise the overall levels of privacy between dwellings and other residential buildings.

Good design practice detailing at key junctions is provided throughout the new Approved Document E. Such as solid constructions are clearly identified in terms of the minimum acceptable mass of the masonry leaf. Solutions are presented showing the essential gap filling, joint sealing, fire stopping, cavity closing and continuity of insulation to prevent sound transmission through critical junctions.

POINTS FOR PARTICULAR ATTENTION

Separating walls

Masonry construction

 Fill mortar joints and if using bricks lay frog up to achieve the mass and avoid air paths
 Unless blocks are known to be acoustically impermeable with no air paths through the block they should be plastered or receive a parge coat prior to dry lining. It is not recommended that autoclaved aerated concrete blocks are treated with a parge coat prior to dry lining as experience has shown that this can have a negative effect on the acoustic performance of the finished wall
 In cavity walls maintain the cavity up to the underside of the roof. Connect the leaves only where necessary using butterfly ties spaced as required for structural purposes
 If external walls are to be cavity filled with thermal insulation material other than un-bonded particles or fibres (e.g. foam boards), the insulation material should be prevented from entering the cavity of the separating wall using a flexible cavity closer
 Plasterboard dry lining systems should be installed in accordance with manufacturers’ details to ensure that optimum acoustic performance is achieved. Robust Standard Details are likely to incorporate plasterboard having a mass of at least 10kg/m2.

Light weight framed construction

 When using twin frame construction only connect the frames where necessary for structural reasons and using as few ties as possible
 Socket outlets should be located away from separating walls
 Where fire stops are required in the cavity between the frames they should be either flexible or fixed only to one frame

Separating floors

 Fill all the joints between the different elements of concrete floors to avoid direct air paths
 Control sound paths around the floor to reduce flanking transmission
 Workmanship and detailing should be given special attention at the perimeter and wherever the floor in penetrated
 Care should be taken not to bridge the floating layer at the base, the surrounding walls or where the screed abuts
 A levelling screed may be required particularly if the floor includes 5mm polyethylene foam as a resilient layer, as discontinuity in the floor finish can cause bridging of the resilient layer
 In timber or steel joist floors ensure that the correct density of resilient layer is used to carry the anticipated floor loading and taking care not to bridge this floating layer – particularly relevant in buildings other than dwellings where floor loadings are often higher

GPDA Advice Note

24 January 2003

FIRE RESISTANCE
BACKGROUND

The current version of approved document B (England and Wales) came into force in July 2001

Proposed amendments will harmonise Building Regulations with recently introduced European legislation. This will take the form of a European Supplement, which will identify the appropriate technical specifications and supporting European test standards. The Office of the Deputy Prime Minister expects to publish the European Supplement at a later stage.

In practical terms, the effect is that material will have to be tested in accordance with the European Standards, and classified appropriately. The new tests will measure fire reaction and resistance, and some materials may be reclassified under the British Standards.

FIRE RESISTANCE TESTS

A material’s fire resistance is defined as its ability to withstand the effects of fire over a specified period of time without losing its fire-spreading or loadbearing functions. It is used to test walls, columns, floors, doors and even ductwork.

In the case of fire-resistance tests on construction, systems research shows that products tested by the European method record times that are, on average, 10-15% shorter than for those tested by the British Standards methods. For example, a product achieving 60 minutes under the British Standards test may only achieve 50-55 minutes under the European harmonised test.

The implication for the industry is that it will have to adapt its products, where necessary, to meet the 10-15% shortfall in test times.

For example, this may result in steel requiring more fire protection, or thicker sections of timber being added to achieve improved fire resistance.

THE EFFECT OF THE CHANGES

This has involved the re-testing of proprietary systems against the new test conditions. In due course modified system performance will be available from each manufacturer.

Member companies within the GPDA have been active in developing solutions to meet the new standards. It should be noted that the statutory requirement to comply with the new standards has not yet been agreed, but it could be as soon as 2005.

The introduction of the new EN fire resistance and reaction to fire test methods will not however dramatically effect the forms of construction currently promoted by plasterboard manufacturers. Solutions are available and in the majority of cases simply switching from a 12.5mm to a 15mm board thickness will be sufficient to meet the new performance standard. The only area where a more radical solution may be required is when fire rated partition’s are specified at heights above 4m. In most situations cost-effective alternative solutions are available using proprietary plasterboard systems and the advice of the individual plasterboard manufacturers should be sought for more detailed information.

EN REACTION TO FIRE

Under the current UK system for classifying the reaction to fire performance of building products plasterboard falls into the Building Regulations defined category of “material of limited combustibility”. Under the Euroclass system Type 1 wallboard is classified after testing as Euroclass A2, the second highest performance level. In the consultation package published by DTRL a material of limited combustibility is equated to Euroclass A2 and hence there is no change in the potential usage of wallboard on reaction to fire grounds.

EN FIRE RESISTANCE

SEVERITY

The introduction of the new European test for fire resistance BS EN 1363-1 will increase the severity of fire resistance testing in the UK. The reason for the increase in severity is the adoption of the plate thermometer, which is the device used by test houses to measure the temperature within the furnace. This new device gives a lower reading of temperature within the furnace and requires more heat energy to be inputted especially during the early stages of the test. This effect is shown in Figure 1 where the temperature recorded by the old measuring device is shown whilst the furnace is controlled with the new plate thermometer. The RADAR 1 project sponsored by DTRL, which examined the differences between the current British and new European test standards estimates that, the increase in severity to be on average between 10 – 15%.

FIELD OF APPLICATION

The new European test standard introduces a new concept which limits the end use conditions that a test result may be used to substantiate e.g. height, width, thickness, stud size, joint detailing etc. This limit on the test results use is termed the Direct Field of Application and if a manufacturer wishes to extend the result beyond the direct field of application then an extended field of application assessment is required. Ultimately rules for extended application will be set by CEN for use across Europe but at present no agreed rules exist in Europe and progress will be slow. In the UK the Fire Test Study Group (FTSG) have agreed a limited set of assessment principles which can be used within the UK until rules are agreed and issued by CEN.

NON-LOADBEARING PARTITIONS

The new EN 1364-1 test method as stated above is more severe than the old BS 476:Part 22 test and consequently the performance of a basic partition lined with Type 1 wallboard will be downgraded when used in non-loadbearing partition applications. The main consequence for Type 1 wallboard is generally that systems that had a small safety margin when tested previously to the BS test standard will now fail. In most cases a 12.5mm wallboard can be replaced with 15mm wallboard in order to maintain the equivalent fire resistance duration.

In addition to the severity issue the Direct Field of Application places limits on the partition height that can be claimed in relation to fire resistance duration. The rules state that if a test specimen deflects laterally by more than 100mm during the fire resistance test then the height of the partition must be limited to 3m in the fire condition. If the partition deflects less than 100mm then the partition can be used in situations up to 4m in height. An extended application assessment is required for all fire claims made at heights greater than 4m, a calculation method has been adopted by the FTSG for use in the UK which allows a partition tested at 3m to be assessed for suitability at heights above 4m. The result of using this method is that the partition specification again needs to be enhanced. The figure below shows the performance in terms of fire resistance and height to be expected for a standard 70mm metal C stud partition lined with wallboard.

Partition Height	Fire Resistance
	30 minutes	60 minutes
Up to 4m	1 x 15mm wallboard	2 x 15mm wallboard
Greater than 4m	2 x 12.5mm wallboard	Solution required

The solution given for the partition at a height greater than 4m is very robust and lesser board specifications may be viable if a full engineering assessment is conducted. Another implication of the partition height issue is that partitions specified above 3m need to have a separate evaluation for situations where insulation material is incorporated within the partition cavity as the presence of the quilt will influence the thermal bow of the partition system.

LOADED PARTITIONS

As with non-loadbearing partitions the change in severity has affected the performance of partitions and has necessitated the enhancement of the plasterboard lining in situations where little safety margin previously existed. Again in general terms where a 12.5mm wallboard was used previously a 15mm wallboard may now be required. It is also still possible to use 38mm wide timber sections in some applications.

TIMBER JOIST FLOORS

As with partitions the severity increase has necessitated in some cases an enhancement of the floor specification in order to maintain fire resistance duration. However it is still possible to achieve a full 30 minutes using a noggin less 15mm wallboard specification. It is also still possible to use 38mm wide timber sections in some applications. The proposed changes to Approved Document B also means that the construction presently used to achieve a half-hour modified floor will remain unaltered.

PRESS RELEASE

11 December 2002

PLASTERBOARD CONTRIBUTION TO RACKING STRENGTH ‘UNDERRATED’
Tests conducted as part of the TF2000 Core programme provided for the first time an insight into the actual performance of a complete timber frame building, not just of its component parts but the enhanced structural performance of timber, structural sheathing, plasterboard lining and brick cladding when these components interact. One of the test series in the core programme identified the lateral or racking stiffness at different stages of construction in order to determine the contribution of both structural and non-structural elements to the overall building stiffness.

The results formed the basis for a ‘Partners in Innovation’ project “Re-evaluation of plasterboard in wall racking”, with the main aim of improving timber frame design codes and building efficiency using the TF2000 wall racking data This highlighted a potential vast level of conservatism in the present design method for racking resistance of timber frame buildings. It is clear from the final/closing report that plasterboard requirements of design and construction have been recommended for improvement in the design codes based on the outcome of the project and the work of the TF2000 project.

Test results of the TF2000 building have shown that the plasterboard lining and brickwork cladding play a major role in contributing to the racking resistance of the whole building, producing a combined increase in stiffness over the timber frame by a factor of 3.3 to 17.5, depending on the building axis considered. These results are all the more convincing considering that they were established by applying a 50-year return period wind load to the TF2000 building, which only deflected on the top floor by ± 1mm when the building was complete.

One of the main technical objectives to the project had been establishing the reserves of strength in the building and identifying components of the construction and design that may account for these reserves. This included a series of racking tests that studied in greater depth the influence of plasterboard linings.

The test report produced by Dr Griffiths and Ms Bregulla at Surrey University has produced the most compelling evidence for changes to the design codes, although the scope of potential changes has been only small. This project has also identified the omissions or potential amendments to British standards BS5268: Part 6: Sections 6.1 and 6.2:

• Screws are increasingly used for fixing plasterboard. Specifications for their fixing and application should be include following the recommendations of the report.


• Limits on the construction of plasterboard have been shown to be very conservative and may be revised in the light of new evidence.