News

Dec 2011 New SPRA Quality Standard for expanded polystyrene insulation

Jusr released the new SPRA Quality Standard; Expanded polystyrene roofing boards for inverted roofs.

Nov 2011 Apprenticeship scheme moves forward

Single ply SAP moves forward

The new specialist apprenticeship programme for single ply roofing will launch early in 2012 with a pilot based in the East Midlands.

Thanks to strong support from local employers,there are enough candidates to start the two-year programme, which culminates in achievement of the NVQ Level 2 for applied waterproof membranes – single ply roofing.

Candidates will also be offered product-specific training by the employer’s preferred membranemanufacturer, the so-called ‘ticket’ that meets the requirements of the Single Ply Roofing Association. Off-site training will be delivered at the East Midlands Roofing Centre in Bulwell, Nottingham,while Construction Skills National Specialist Accredited Centre (NSAC) in Leicester will provide the assessment centre role.

Trainers have been selected because of their wide and long experience, not only on the tools,but also in delivering high quality training at membrane manufacturers’ own training centres.

If the pilot proves successful in the early phase, SPRA will offer the SAP from other training centres – especially those managed by regional roofing training groups – chosen for their location and facilities. The structure of the apprenticeship is designed to avoid block release and maximise the productivity of candidates for their employers, for example by allowing suitably motivated and organised candidates to complete their product training at an early stage in the process.

Single ply roofs are systems of deck, vapour control, insulation, waterproofing and ancillary components. Manufacturers from each of these sectors will provide complementary training and demonstrations on a strictly generic basis. Employers interested in registering possible candidates in 2012 and beyond should contact Eve Erentz at Single Ply Roofing Association on 0115 914 4445 or This e-mail address is being protected from spambots. You need JavaScript enabled to view it

Oct 2011 Wind load design part 2

Wind load design requirements for flat roofing – Part 2

title Martyn Holloway, Chairman of SPRA Technical Committee and Flat Roof Applications Manager at SFS Intec Limited, introduces the second part to his series on wind loading (view for Part 1).

Assessment of the effect of wind load is a fundamental requirement of the design process for any roof construction. This may sound obvious, but in a world of constantly changing design standards and construction methods, important issues can be overlooked.

Designers must ensure that the correct calculation procedure is followed. For the UK this is BS EN 1991-1-4:2005 + A1:2010: This standard must also be used in conjunction with The UK National Annex: NA to BS EN 1991-1-4:2005 + A1:2010: UK National Annex to Eurocode 1. Note that the previous standard, BS 6399-2 has now been withdrawn. alt

It is essential that all components specified and their method of installation, are able to contend with the calculated wind loads. Incorrect installation of restraint to the deck, insulation and membrane can lead to premature failure of the construction. It is therefore imperative that the designer and contractor are aware of the attachment requirements at each interface, as determined by the wind load calculations undertaken. These will vary with the method of application.

For mechanically fastened membrane applications the correct membrane fastener frequency is determined by the wind load requirement and fastener design load. For new build steel decks for example, where these parameters are known, the fastener frequency can be specified by the SPRA membrane manufacture. For refurbishment and concrete decks however, pullout testing should be undertaken by the fastener supplier/manufacturer to determine by calculation the correct fastener design load. Insulation should also be fixed correctly. For example to comply with BRUFMA requirements, the minimum number of fasteners per insulation board should be determined in accordance with the calculated wind load requirements.

There is one mechanical fastening issue that needs reiterating. In recent years the use of steel stress plates and long fasteners (which create a thermal bridge) has given way to plastic tube thermal break plate/tube components with short fasteners because the latter do not require a compensatory increase in insulation thickness. All SPRA-member insulation manufacturers assume the use of thermal break components in their calculation of required insulation thickness. Thus, although metal components are not contrary to Building Regulations, if they are to be used it will be necessary to check that this compensation has been allowed for in the thermal design or target U-value may not be achieved in practice.

For adh alt ered membrane and insulation applications, the selected system must be suitable to resist the calculated wind load at each interface. Whatever the means of adhesive attachment it is a SPRA requirement that mechanical restraint is installed at the roof perimeter, at changes of slope and around details to ensure that any tension in membrane in the roof field or upstand is not transferred to the other as peeling action.

Ballasted systems should have sufficient mass to meet the requirements of the wind load calculations. This also applies to green roof applications where the "dry" weight of the system may require the membrane to be additionally restrained mechanically or by the use of adhesive to resist wind uplift.

The number of fixings per insulation board varies with wind load

Several useful guides are available at the ‘downloads’ page of the SPRA website.

‘Quality control and use of adhesives for the attachment of vapour control layers, insulation and single ply membranes in flat roofing’ (SGD6/08), which includes checklists.

‘Wind load design requirements for flat roofing - requirements for insulation and single ply membrane’ (SGD/10/11), which highlights specific issues to be addressed by the contractor and designer, including references for further detailed guidance.

July 2011 -It's up there with the best

Think of Norman Foster's extension to the art centre at the University of East Anglia, Richard Rogers at Pompidou Centre, Zaha Hadid's Olympic Aquatics Centre or the fast rising Shard at London Bridge; prestigious high profile buildings. . . read more

July 2011 Getting attached - fasteners update

SPRA director Jim Hooker spoke to Peter Reilly, technical services manager for Associate member SFS Intec.

How is the fastener industry keeping pace with the drive for carbon reduction? Read more

Dec 2010 SPRA Supports Green Deal to upgrade housing

The government’s Green Deal is being delivered through the Department of Energy & Climate Change www.decc.gov.uk . SPRA will be working with the Construction Products Association to establish a list of products suitable for upgrading the energy performance of residential buildings. SPRA Associates supply a wide range of insulation, fasteners and rooflights, all of which can be used to upgrade the existing housing stock. Key product attributes include thermal resistance, durability, air permeability and solar reflectivity. The full schedule will be available at this site very shortly.

Nov 2010 SPRA campaigns for clarity on Part L2B

The Building Regulations 2000 Approved document Part L 2010 aims to achieve an overall 25% saving in carbon output from new UK buildings when compared with the 2006 version. It also seeks to ensure energy efficiency is upgraded during substantial refurbishment of existing buildings. Yet SPRA understands that a major opportunity to improve energy efficiency in roofing will be missed because of interpretation of the new Part L2B for exiting non-dwellings. SPRA Director Jim Hooker sums up the problem in his enquiry to the Department of Communities and Local Government:

“I have a particular concern regarding the interpretation of ADL2B in respect of membrane or ‘flat’ roofing.

Clause 5.8(b): ‘replacing the water proof membrane on a flat roof.’

The word ‘replacing’ implies the removal of the existing and installation of new waterproof covering. That is clear enough, but does not take account of the overlaying of an existing failed or perished waterproofing with another. Typical examples of this include the following:

· Mastic asphalt (which is expensive to remove) is retained and covered with bitumen or single ply membrane, or coated with a site-applied polymeric liquid waterproofing.

· Single ply membrane is overlaid with a new layer and restrained by mechanical fastening or ballasting. It may also be coated with a site-applied polymeric liquid waterproofing.

· Built-up bitumen membrane is retained, repaired and covered with additional bitumen or single ply membrane, or coated with a site-applied polymeric liquid waterproofing.

· Liquid-applied membrane is cleaned and over-coated with a similar product.

The durability of such systems is increasing, thus extending to as much as twenty years the period before an opportunity will next arise to upgrade thermal performance. The cost difference between ‘option 1’ (an overlay) and ‘option 2’ (a thermal upgrade) is widening so the building owner, who for this type of work may be the direct employer of the roofing contractor, may be further discouraged from taking up the opportunity for carbon saving.

‘Replacing’ could also mean removing the waterproofing membrane, whilst retaining the other components beneath it, usually thermal insulation and vapour control layer. I assume that this circumstance would come within the scope of L2B:2010 as would the complete stripping down to the supporting deck but again this is not clear. However, this practice is increasingly rare, because of the alternatives available and because it exposes the roof to the elements; impractical if there is continuous occupation of the building.”

Nov 2010 New guidance on falls and drainage

Falls and Drainage for single ply roofs [Adobe Acrobat PDF - 186.66 KB] includes falls checklist

July 2010 SPRA opposes delay with Part L

Part L The 2010 version of the Building Regulations Approved document Part L is due for implementation on 1^st October. There are moves to delay this on the grounds that the national calculation methods (SAP for dwellings and SBEM for non-dwellings) are not sufficiently reliable to enable design for carbon reduction. SPRA recognises these problems but argues that any delay now will have implications for the overall carbon reduction target leading to ‘zero carbon’ (net, from buildings) by 2020. SPRA believes that problems with the calculation method should be resolved between developers and their designers and the building control bodies but must not be allowed to slow the carbon reduction process because there are likely to be far more serious technical challenges ahead.

July 2010 New guidance on guarantees

title The revised guide includes new criteria adopted by our membrane manufacturers.

July 2010 New apprenticeship for single ply roofing

SPRA Council has agreed to push on with a new two-year ‘Specialist Apprenticeship Programme’ for new entrants to single ply roofing. The apprenticeship will be available from 2011 and will include not only key skills and health and safety training but also product-specific training by the manufacturer(s) whose products the candidate’s employer currently installs. The successful candidate will complete the apprenticeship by attainment of NVQ Level 2 in Applied waterproof membranes – single ply roofing.

June 2010 Research on wind loading

Accurate calculation of wind loads acting on roofs is crucial for design. SPRA members apply safety factors to the means of attachment (mechanical, adhesion, ballast) to ensure a wide margin of security. SPRA Technical Committee has appointed a task group to review the new calculation method EN1991-1-4 which is due to replace the existing (BS6399 Part 2) during 2010. The task group has taken a series of notional buildings in various UK locations and compared the wind loads calculated by these methods. A preliminary report is available here

June 2010 Special task group to investigate adhesives

A special meeting of SPRA members and manufacturers of polyurethane-based adhesives will be held in July. This will follow on from the work completed in 2008 to produce a checklist for quality control alt

guide SGD6/08 [ 513.17 KB] The group will agree test criteria for the performance of adhesives used in several situations in single pl

y (and other) roofing:

Vapour control layer to deck.
Insulation to vapour control layer.
Insulation to insulation (multi-layer situations such as tapered insulation schemes).
Single ply membrane to insulation.

June 2010 SPRA techical guidance - authority through experience

Technical committee chairman Martyn Holloway has presided over a new style for the ‘highly respected SPRA Technical Committee’. Membership growth has dictated that this group, which represents membrane manufacturers, associate component manufacturers and contractor representatives, now manages a series of task groups. Read more.. alt

RCI editorial [54.54 KB]

May 2010 Delomac Roofing wins at the National Roofing Awards

SPRA member Delomac Roofing won the Best Single Ply Roof at the National Roofing Awards held on 14 May at the Novotel Hammersmith. The project was the refurbishment of Frobisher Crescent, Barbican. Delomac were commended for the standard achieved in the complex barrel-vault design, which involved thermal upgrading and mechanical fixing to the existing structure. The work was undertaken during occupation of the interior.