Market leading roofing manufacturer, Sika, has launched a complete Green Roof package, supplying both the high performance roof waterproofing system and the green roof system, all backed by its trusted technical and application support.

Specifiers can now go to Sika’s roofing experts for the full spectrum of roofing technologies, from hot melt structural waterproofing and reinforced bituminous membranes to single ply and cold-applied liquid membranes, depending on what is best for the project in question, all of which can now be laid with a Sika Green Roof system on top. The new systems are manufactured in the UK and are available in three of the most common green roof types — extensive, intensive and biodiverse.
Sika not only supplies all the materials required for the whole green roofing project, it also lends its invaluable expertise and support throughout. The Sika Roofing team are on hand to aid with initial design, technical calculations and specification through to installation, site inspections and final sign off. Further peace of mind is achieved thanks to Sika’s UK-wide network of Certified Roofing Contractors, all fully trained to deliver high quality results.
With sustainable development a key focus in construction, backed by the government and local authorities, the benefits of a Sika Green Roof cannot be overstated. Multiple studies have shown that green roofing systems can improve air quality, reduce the urban heat island effect, maintain or even increase biodiversity, improve a building’s thermal performance and manage stormwater throughout the year — particularly important in areas of flooding or where Sustainable Drainage Systems (SuDS) are a design consideration.
In addition, green roofs can also reduce noise penetrating through the roof, energy use and building running costs, all while extending the life of the waterproofing underneath. It has been suggested that in some cases that a building with a green roof installed may never need a new roof (Aldred 2019) — a significant consideration when calculating the whole life cycle sustainability of building materials.

Sarah Peake, Sika’s Sustainability Manager, said: “The construction of new buildings can play a huge role in contributing to the world’s sustainability targets and green roofs are part of the
solution. The fact that the green roof market is growing by approximately 17 percent per year speaks for itself.
“Thanks to its numerous eco-benefits, a Sika Green Roof can help architects hit sustainable development targets and achieve an improved rating from schemes such as BREEAM and
WELL, which are instrumental in helping us build for a better future.”

As a global company, Sika’s dedication to the environment is of utmost importance. The company’s robust Sustainability Strategy is focused on the principle of ‘More value, less impact’ and as members of the United Nations Global Compact, Sika has aligned its activities to the UN Sustainable Development Goals. As well as offering a whole host of sustainable solutions for the construction industry, of which green roofing is just one example, it also implements a holistic approach with targets covering climate performance, local communities, reduced resource consumption and occupational safety.

If you would like to find out more about Sika Green Roof or its whole range of roofing solutions and services, call 01707 394444, email enquiries@uk.sika.com or visit www.sika.co.uk/roofing.

Craig Smith, Business Development Director – Roofing for TN International, advises specifiers and building owners on the latest fire safety requirements.

Fire safety has always been a priority in the construction industry, and flat roofing systems had to comply with stringent fire performance criteria for many years. However, since the Grenfell disaster in 2017 the flat roofing sector, like the rest of the industry, has had to closely examine how standards can be improved further.
Today, it is more important than ever that specifiers and building owners understand the latest fire safety requirements so they can make informed decisions on the safest, most effective products to use.
So, exactly who is responsible for fire safety in flat roofing? The reality is that fire responsibilities are shared between all parties involved in the design, approval, manufacturing, construction and sign-off of flat roofing systems.
However, the most responsible individuals are the fire consultant specialists and Building Control consultants who must check every detail of the roofing system manufacturer’s data and any third-party accreditation to ensure compliance with all necessary requirements. Their judgement will ultimately lead to a particular system being specified or rejected and can have a knock-on impact to whether insurance will be approved.
During 2020, many roofing system design applications were rejected if they did not totally comply with third party accreditation such as fire test and BBA certificates, including the type and thickness of insulation.
Flat roof waterproofing systems must comply with all current Building Regulations along with several other potentially confusing tests and standards. It’s obviously important to understand how they should be interpreted to specify an appropriate roof waterproofing system.
The regulations for flat roofs require that the specified flat roof system provides external fire protection from “spread of flame” and “penetration of flame”. For decades, the standard flat roof fire certification in the UK was in accordance with BS476: Part 3:2012 (originally created in 1958) and the flat roofing industry was used to seeking the ultimate fire rating of EXT.F.AA.
In 2016, the UK construction industry entered a transition period to accept a new European fire rating standard – EN 13501-5:2016. This standard incorporates four different European test methods for external fire exposure to flat roofs, derived from the various national test methods.
These European test methods are designated as Broof t1, t2, t3 and t4, with the nearest to the original UK standard being Broof (t4). This is also the most stringent standard to achieve as the testing is done in two stages, with the system exposed to burning brands, wind and supplementary radiant heat.
It was subsequently agreed that all future UK external fire exposure ratings for flat roof systems would conform with the new set of European fire standards, with the highest rated systems needing to achieve a Broof (t4) rating, using test CEN/TS1187:2012 in accordance with EN 13501-5:2016.
So, how do manufacturers achieve a Broof (t4) fire rating? Flat roofing system external fire tests are performed by accredited institutions such as the BRE or Warringtonfire. These organisations have specialist testing facilities which expose the full roof system assembly to flame and radiant heat in accordance with the CEN/TS1187:2012 testing methodology.
For a warm roof system, the typical build-up comprises an exposed membrane (the cap sheet/top layer), an optional underlay, thermal insulation, vapour control layer and structural deck. During testing, the exposed membranes must withstand flames and high radiant temperatures being applied to their surface for periods of time using parameters set out in CEN/TS1187:2012.
An independent fire rating is then attributed to the system, depending on its performance, with Broof (t4) being the highest rating possible. Among other factors, this rating will dictate the minimum distance the system can be installed in relation to the roof boundary and adjacent building.
Although some of the system components may be combustible, they are fully protected by the exposed cap sheet membrane. It is essentially this top-layer membrane which provides the Broof (t4) rating and enables the system to comply with the UK’s fire regulations and national building regulations.
Inverted roof assemblies include waterproofing membranes which are subsequently protected by insulation and a water flow reducing layer, and this is then usually covered by non-combustible ballast materials like concrete paving slabs and stone pebbles.
As such, most manufacturers of inverted roof waterproofing systems do not have their assemblies fire tested. The main reason is there is a European Communities Commission Decision 2000/553/EC (September 2000) which states that any flat roofing assembly with certain non-combustible coverings (concrete paving, stone pebbles, concrete) “can be considered to fulfil all of the requirements for the performance characteristic ‘external fire performance’ without the need for testing”.
The previous external fire rating standards mentioned, notably BS EN 13501-5, related to complete flat roof systems. However, this should not be confused with another European standard that exists – BS EN 13501-1. This provides “the reaction to fire” classification procedure for all construction products, including individual products within building elements and systems.
The BS EN 13501-1 classification comprises of three ratings:
A1 – F: Combustibility of the individual materials
s1 – s3: Smoke omission during combustion
d0 – d2: Droplets during combustion
The ultimate rating for a product would therefore be classified as – A1-s1, d0.
Flat roofing systems include several components which would be tested individually for their reaction to fire in accordance with BS EN 13501-1. The flexible waterproofing membrane on top would usually achieve an E rating whilst the insulation would achieve anything from A1 to F. In terms of the substrate, both concrete and metal structural decks are classed as non-combustible and therefore exceed the minimum accepted rating of B2-s3,d2 or better. Timber decks, although combustible, may sometimes be the subject of “Special Applications for Purpose Groups” where, if the roof is not more than 15m high, it allows materials rated Class B-s3, d2 or worse”.
Although the structural deck and insulation are important, the waterproofing material is essential. The waterproofing material for flat roofs needs to be flexible and easy to install, and typically these products will have a Euroclass E rating (BS EN 13501-1).
However, those that have achieved a Broof (t4) external fire rating as part of a designated flat roof system (BS EN 13501-5) will also fully comply with national building regulations due to the warm roof cap sheet material containing fire retardant additives, or a non-combustible covering being installed.
It should be noted that although some of the components of a flat roof assembly may be certified combustible in relation to BS EN 13501-1, collectively in a full roof system assembly with a fire rated cap sheet (warm roofs) or fire rated covering (inverted roofs) they may achieve a Broof (t4) in relation to BS EN 13501-5 and fully comply with current national building regulations.
Key tips for specifiers assessing the fire credentials of a particular system are:
Ensure there is evidence of third-party accreditation from a recognised testing authority such as the BBA, BRE or WarringtonFire.
Look for details within the fire section of the manufacturer’s BBA certificate or ask to see the full Broof (t4) fire test report from the recognised testing authority.
Ensure the data provided covers the roof assembly specification being promoted for the specific project. All components, product names and material performance information must be consistent.
Check the specified type and thickness of insulation is covered by the appropriate fire test. Several manufacturers only have fire test data showing one thickness, such as 120mm PIR, and this data is being rejected if the insulation thickness required is different. The assessors will not accept alternative materials to those tested and will not take risks due to legal and professional restraints.

www.tnroofingsystems.com

LIQUID SOLUTION: Trusted partners ensure schools trust is free from worry with flat roof refurbishment.

Desire to deliver a safe learning environment for the children in its care prompted Knowledge School Trust to address the crucial upgrading of the roofs at West London Free School.

The school delivers education for primary and secondary pupils across two sites in Hammersmith. Both estates had roofs at least 30 years old, which had outlived their serviceable life, receiving yearly significant ongoing patch repairs. Water was penetrating through the woodwool slab and asphalt into the building fabric causing structural deterioration, leaking into classrooms, creating mould. Aged rooflights had become fragile. The thermal U-value for the roofs at the primary school was extremely poor and possibly contributing to heating costs the school sites incurred.
To strip the roof back to the decking would have been impractical due to the significant amount of roof-mounted plant and disruption caused to the school sites. Therefore the Trust turned to specialist education consultants Barker Associates to manage the project and upgrading of the roof estates, who in turn called in Langley Waterproofing Systems Ltd.

 

After conducting detailed roof condition surveys across both sites, Langley advised that where practical the existing coverings could be overlaid, and a strip up to deck undertaken only where necessary, saving on site disruption, landfill costs and limiting carbon footprint.
Because of the quantity of roof plant particularly at the secondary school site, including solar panels, extractor fans and ventilation ductwork that would have to remain in situ, Langley advised overlaying with its PC-25 Paracoat Liquid Roofing System, warm roof application on the primary site and cold roof on the secondary site, as the safest, most efficient solution, eliminating any need to undertake hot works and use of gas guns. The same system could be used on both sites, further simplifying the Trust’s estate management going forward.

Langley’s PC-25 system is a two-layer, cold-applied liquid waterproofing solution based round Paracoat high performance moisture triggered polyurethane to achieve a seamless, durable, long-lasting waterproofing for flat and pitched roofs. Installed in conjunction with Langley’s Parafoam PIR insulation 120mm board, it achieves thermal performance of 0.18W/m2K in line with current Building Regulations.
Heartfelt Roofing won the tenders to deliver the works in two phases, addressing first the Primary school in Cambridge Grove before moving to the Secondary site in King Street.

Over the two years of the complete programme, Heartfelt prepared the roof areas, raising window and door cills, kerbs and outlets as required to give 150mm clearance above the new roof surface covering, and removing the fragile rooflights.

Heartfelt , in accordance with the bespoke detailed Langley specification,  overlaid existing coverings with Paracoat primer, added Paratene aluminium foil-faced carrier membrane, installed the tapered Parafoam PIR insulation where needed on the mix of cold and warm roofs, then applied the Paracoat Base Coat with Langley’s GFM embedment fleece, Paracoat Intermediate Coat and finished with Paracoat Top Coat in grey. At the secondary school, the designed walkway to the PV panels was finished with Paracoat Top Coat in red, to define the access separate to the main roof field.

All internal outlets were upgraded using ParaFurb Refurbishment Outlet. Abutments and skirtings were upgraded with ParaFlash B3 lead-free detailing membrane. Existing lead chutes were upgraded with Code 5 lead.

The old rooflights were replaced with Langley’s ParaDome Modular Rooflights. The triple skin polycarbonate glazed units featured a clear outer and middle layer with diffused inner to balance thermal insulation with light transmission without solar glare, ideal for the learning environment beneath, all fitted with manual controlled ventilation.

 


Explained Graham White of Heartfelt Roofing, “Both schools were fully operational below us whilst the works were carried out. It was of paramount importance to the Trust that the programme delivered optimum safety and security, whilst the work was being done, and for the long-term future. Using Langley’s PC-25 system meant we could efficiently meet those objectives. The roof could be upgraded with minimal disruption to day- to-day school life: it avoided having to employ cranes to remove plant, there were no hot works, and the resultant roof and accessories are guaranteed to perform for at least 25 years.”
Added Stewart Keiller, Operations Director at Knowledge School Trust, “Barker Associates are the Trust’s trusted building advisors, giving us a reliable, good service. We were more than happy to accept its recommendation to use Langley Waterproofing Systems, giving us a single source of accountability across the estate for West London Free School.

“Langley listened to our requirements and delivered a solution that would satisfy our needs for the long term:  the 25 year independently insurance backed guarantee on completion by Langley gives us complete peace of mind as it covers design, materials and workmanship.”

RBM SOLUTION: Strong partnership reinforces benefits of investing in educational estate.

The potential challenges faced in managing a school estate of more than 30 roof areas has been alleviated for South Wigston High School through timely use of a proven partnership chain.
The School Business Manager (SBM) Jacqui Cox had discovered internal damage to the building fabric, partly because some of the 17 flat roofs that form the central quadrangle of the educational site were found to be leaking. She turned to MAC Construction Consultants for assistance.

At MAC Construction Consultants’ commission, Langley conducted a detailed roof condition survey and collated a detailed report, confirming the roofs that were in urgent need of attention. This information was then used to support MAC Construction Consultants’ CIF bid for the school to receive funding, which was successful. Central Roofing & Building Services- one of Langley’s nationwide network of Approved Contractors, won the contract under competitive tender.

Central Roofing overlaid 13 of the roofs with Langley’s TA-25 Flat Roofing System. An overlay is a cost-effective option in enhancing the lifespan of roof estates, as it utilises the existing roof. This also supports a carbon reduction, due to the roof not being stripped off and transported to landfill.

The premium quality, high performance SBS elastomeric membrane warm roof system for flat or sloping roofs carries a 25 year independently insured guarantee for materials, design, workmanship and consequential loss. It also enabled an easy upgrading of the thermal performance to the required 0.18W/m2K to meet current Building Regulations.
A single roof was in such a poor state of repair the existing overlay was partially stripped off, and the deck prepared to receive the new waterproofing system.

Central Roofing upgraded a further two covered walkways between buildings by overlaying the existing roofing using Langley’s TA-25 Flat Roofing System (cold roof application).
Across the roof areas, existing lead outlets, flashings and chutes were upgraded and replaced with Code 5 lead. Parapets were overclad in ply to avoid cold bridging and Langley’s Paratrim GRP edge trim installed. Where required, chases were made good and new Damp Proof Courses and cavity trays installed. Integral gutters adjacent to windows were upgraded and insulated.

Langley’s PC-25 C Paracoat Liquid Roofing System was chosen to upgrade the waterproofing on the remaining two roofs: the cold applied liquid roofing system was judged to be the most efficient means of over-roofing the existing substrates: the liquid roofing enabled height restrictions on upstands to be accommodated whilst delivering the weatherproofing required. Part of the Langley Paracoat range, PC-25 C is an advanced, single pack high performance, moisture-triggered polyurethane three-coat waterproofing system that carries a 25 year guarantee for both materials and workmanship. It is robust yet flexible.

Central Roofing & Building further raised low level window cills to 150mm above the finished level of the new roof surface and fitted integrated insulated gutters. The cills, plus additional details and flashings were finished with Paraflash B3 lead-free trim.  The 10 existing rooflights were all removed, the openings of three Georgian wired versions were boarded over as being now deemed surplus to requirements.  The modular rooflights were refurbished with new Langley Paradome triple skin polycarbonate rooflights. The three structural rooflights, one was deemed adequate with appropriate replacement of its integral gutter, and the other two were replaced in their entirety by triple skin polycarbonate versions.

“It took three years in total, it was such a complex project, although the on-site element was executed in under six months,” explained Langley’s Regional Manager Phil Chell. “The one consistency was that all 17 flat roofs failed to comply with current thermal performance, although even the amount of insulation present varied from roof to roof.
“We had at least three different types of existing roof covering to address- felt, asphalt, BUR. We had a number of rooftop services and penetrations to address and upgrade too, including Georgian wired rooflights, lanterns, modular and structural rooflights, plus low level windows, a door threshold and lead outlets and chutes.”
Added Hannah Hughes, Central Roofing & Building Services Business Development Manager, “The project at South Wigston was an excellent example of working partnership between Langley and ourselves. Throughout the time on-site, Langley’s product deliveries arrived on time allowing us to deliver the project accurately and expediently. Langley’s technical team gave excellent communication and help, being on hand to assist with any awkward detailing or technicalities along the way.”
Aaron Webb, Senior Surveyor at Mac Construction Consultants, observed “As the school’s chosen consultants, South Wigston High School roofing replacement scheme was a great project, delivered on time and within budget. The usual difficulties were faced on a large scale school project in terms of logistics and ensuring minimal disruption to the school. The difficulties were eased by the on site management and Langley support. We were pleased with the attention to detail and workmanship ensured by both Langley and Central, subsequently leaving the school with high performing roofs for many years ahead.”
Jacqui Cox, South Wigston business manager summarised, “Through Langley’s efforts I now have an estate of waterproofed flat roofs that I can rest assured will keep students and staff safe and warm for years to come. Langley went beyond what I would have expected in its level of support to the school in delivering this project.”

 

www.langley.co.uk

 

 

ROCKWOOL delivers proven insulation performance for Clarin College flat roof

Priority Roofing has installed over 7,500m2 of ROCKWOOL HARDROCK® Multi-Fix Dual Density for the new secondary school development at Clarin College, Athenry. In supplying the non-combustible insulation solution, ROCKWOOL enabled the roofing contractor to deliver against a complex specification which required thermal and acoustic performance without compromising on fire safety.

For Clarin College’s 6,500m2 general building and 1,000m2 gymnasium, Healy Partners Architects specified a warm flat roof build up which would help achieve an indoor ambient noise level (IANL) of 35dB, as per the requirements of SDG 02-05-03 (Acoustic Performance in New Primary & Post Primary School Buildings).

It was also essential that the general performance requirements of TGD 021-7 (Minimum Performance Standards of Roof Materials and Finishes) were met, and the specification defined a target U-value of 0.16 W/m2K to exceed the thermal requirement for flat roofs in schools as per Technical Guidance Document L. Having attended ROCKWOOL CPD sessions on the role of insulation in schools, Healy Partners Architects also took the best practice approach of specifying non-combustible insulation across the entirety of the two flat roofs.

Using non-combustible insulation across the entire flat roof is an increasingly common trend among designers, and doing so helped Priority Roofing to reduce zoning concerns and simplify the installation process.

As a non-combustible insulation solution, ROCKWOOL HARDROCK® Multi-Fix Dual Density met the fire safety requirements while also delivering against the thermal and acoustic targets. Clarin College’s new flat roof achieved a U-value of 0.15 W/m2K, and met or exceeded the 35 db IANL requirement across both the general building and the gymnasium. To combat reverberation and improve the acoustic environment in the gymnasium, ROCKWOOL Acoustic Infills were laid in the troughs of the pre-finished steel deck. The warm flat roof build up was finished with a Bauder Thermofol PVC layer.

Kevin Ryan, Director at Priority Roofing, commented: “We have worked with Bauder and ROCKWOOL on a couple of large projects installing both bituminous and single ply systems. We found the system both practical and efficient to install. The combination of the availability of the products and the technical backup received was superior to any other system that we have worked with.”

 

To find out more about how ROCKWOOL supported the new flat roof construction at Clarin College, PLEASE CLICK HERE:

 

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Southern Industrial Roofing has installed over 2,000m2 of ROCKWOOL HARDROCK® Multi-Fix Dual Density at the new-build Cobham Free School, Surrey. Meeting a complex warm flat roof specification, ROCKWOOL delivered a non-combustible solution with proven acoustic and thermal performance.

The project had to balance multiple design considerations, starting with BS 6229: ‘Flat roofs with continuously supported flexible waterproof coverings’, and compliance with specific education sector building regulations. While BB93 specified acceptable levels of rain noise transfer into various spaces, BB100 outlined fire protection considerations.

Simultaneously addressing these requirements was compounded by mechanical and electrical plant being housed on the flat roof, which demanded non-combustible zones to provide safe access for maintenance. Internal fire rated walls in the building below also required the flat roof to contribute to effective compartmentation.

As non-combustible stone wool insulation, specifying ROCKWOOL HARDROCK® Multi-Fix Dual Density across the entirety of the flat roof streamlined the installation process. Where the roof deck interfaced with the heads of internal compartment walls, ROCKWOOL Trapezoidal Fire Stops were also installed. To minimise acoustic reverberation and achieve BB93 compliance in the dining room and auditorium, ROCKWOOL Acoustic Infills were friction fitted into the perforated metal deck troughs.

Andy Towns, Designer at Southern Industrial Roofing, explained: “We didn’t have to worry about coordinating zones with different materials – it was ROCKWOOL across the board which simultaneously delivered the acoustic, fire and thermal performance we needed.”

To find out more about how ROCKWOOL supported the flat roof construction at Cobham Free School, please CLICK HERE TO VISIT:

 

  

 

About ROCKWOOL UK

ROCKWOOL Limited is part of the ROCKWOOL Group. With one factory based in Bridgend, South Wales and over 500 employees across the UK, we are the local organisation offering a full range of high-performing and sustainable insulation products for the construction industry.

At the ROCKWOOL Group, we are committed to enriching the lives of everyone who experiences our product solutions. Our expertise is perfectly suited to tackle many of today’s biggest sustainability and development challenges, from energy consumption and noise pollution to fire resilience, water scarcity, and flooding. Our product range reflects the diversity of the world’s needs, while supporting our stakeholders in reducing their own carbon footprint.

Stone wool is a versatile material and forms the basis of all our businesses. With more than 11,000 passionate colleagues in 39 countries, we are the world leader in stone wool solutions, from building insulation to acoustic ceilings, external cladding systems to horticultural solutions, engineered fibres for industrial use to insulation for the process industry and marine & offshore.

Sika Sarnafil’s single ply roofing membrane has been installed on the UK’s first dedicated centre for stroke and dementia research at the University of Oxford, providing a long lasting waterproofing solution for this impressive building.

 

The Wolfson Building is situated on the University’s John Radcliffe Hospital site and provides purpose-built facilities for the Wolfson Centre for the Prevention of Stroke and Dementia (CPSD), as well as research space for the Wellcome Centre for Integrative Neuroimaging (WIN).

 

Offering expansive views of the city and its surroundings, the new neuroscience research building’s H-shape floor plan was designed to symbolise the two departments’ collaborative relationship. When it came to the roof, the facility required a robust and fully integrated waterproofing system that would accommodate roof penetrations, walkway and PV requirements.

 

Sika Sarnafil, the UK’s leading single ply roofing manufacturer, was specifically requested for the project by the University of Oxford and came on board during the early design stages to help Oxford-based architect firm fjmt with the specification.

 

Sarnafil’s single ply membrane has been used across many of the University’s existing buildings, including the Department of Chemistry’s new Teaching Laboratories. Highly regarded by the educational establishment for its ease of use, robustness and straightforward maintenance, the client insisted it be used again.

 

Sarnafil G410 12 ELF in Lead Grey along with Sarnavap HD were chosen to weathertight the concrete slab room. Due to an uneven and rough surface, a system had to be specified that would overcome this problem. Roofing contractor Vertec liaised with Sika Sarnafil and opted to mechanically fix the single ply to overcome this.

 

Further challenges were found due to the multiple penetrations in the roof, numbering over 50, including cables, pipework and ducting. Opting to box them in, all penetrations were successfully sealed thanks to expert workmanship from Vertec’s Sika Sarnafil-trained installers.

 

With support from Sika Sarnafil, who oversaw the project and offered advice and knowledge throughout, Vertec was able to get the roof weatherproofed on schedule.

 

The new building now houses a number of research groups and work towards the Prevention of Stroke and Dementia has already led to major changes in clinical practice, such as promoting emergency treatment after minor warning events to improve stroke prevention. Thanks to the expansion of the centre, research such as this will continue to benefit patients.

 

For more information on Sika’s products and services call 01707 394444, email sarnafilroofing@uk.sika.com or visit gbr.sika.com

Ensuring flat roof systems not only meet the functional and budgetary needs of the school but also fully comply with fire regulations is not always simple. Here, Daren Fraser, Head of Technical at Langley Waterproofing Systems Ltd looks at four key points decision makers need to consider to ensure a compliant and safe flat roofing system specification.


1 – Building Regulations Compliance

 

It is crucial that any new or retrofit element of a building complies with the fire safety standards. For flat roof installations, one of the main sources of regulation and guidance in England is Approved Document B (Fire Safety) of the Building Regulations and in particular, Section B4 ‘External Fire Spread’. This section focuses on walls and roofs with ‘resisting fire spread from one building to another’. As such, Approved Document B states minimum distances between buildings and provides a required fire resistance of the materials based on this distance.

 

The required level of fire resistance is demonstrated as the rating that the system achieves against the European test standards. This classifies roof systems into five categories based on their performance – Broof, Croof, Droof, Eroof and Froof. There are also four distinct tests (t1 to t4) each with separate testing procedures designed to meet the specific requirements of different countries – t1 for Germany, t2 for Scandinavia, t3 for France and t4 for the UK. The t4 test has been established to meet the stricter requirements of UK standards so the first step when reviewing a roof specification is to ensure that the selected flat roof system has passed the t4 test and is therefore compliant to Broof(t4).

 

The separation distances and corresponding fire resistance stated in the regulations are designed to protect the roof from fire spreading from other buildings but cannot account for ignition sources that may be closer. Therefore, although a strict reading of Approved Document B might indicate that a system with a lower fire rating is acceptable, this is not recommended. Anything less than a system that meets the Broof(t4) classification means that the building is more susceptible to fire risks.

 

2 – Independent Testing

 

In addition to checking the fire rating, decision makers should fully interrogate the information within a specification to confirm the proposed system complies with Building Regulations. A key source of information is the details published by the system supplier itself and this should be examined to confirm the system has undergone independent testing that verifies any performance data. For example, British Board of Agrément (BBA) certification will confirm compliance with the Building Regulations, outlining all tests carried out and the Broof(t4) classification.

 

3 – No Substitutions – Tested System Approach

 

However, it is important to ensure the system being specified is the same as that which was tested. A common issue is a substitution of components for ones that have not been tested as part of a system. This was among the elements raised in the Hackitt review of Fire Safety and Building Regulations. This not only risks non-compliance but also potentially undermines the safety of the building in the event of a fire.

 

For example, if the system has only been tested and passed with a specific type and thickness of insulation, it is dangerous and poses a risk to assume that it will still perform as expected if this is changed. As well as the safety concern it may invalidate the guarantee provided by independent insurers as it hasn’t met the classification provided to meet the required Building Regulations.

 

Langley’s flat roof systems have been independently tested through the BBA and certified with extensive additional fire testing, varying insulation types and thicknesses and using different roof decks. This means that Langley’s TA Flat Roofing Systems can be used in a range of different configurations to suit the client’s flat roof requirement whilst ensuring full compliance with the regulations. These systems are also LABC Assured; providing further certification on compliance with Building Regulations and standards across England, Wales and Scotland.

 

4 – Approved Contractors

 

A compliant system is required to be competently and expertly installed therefore it is essential that the flat roof is installed by a contractor that is fully trained and the work is monitored throughout to ensure a high standard of installation. Leading system suppliers will be able to provide a database of approved contractors and will guarantee the works covering materials, design and workmanship, providing peace of mind.

 

While a flat roof system might seem to meet all the requirements of the school it is crucial that the details are examined carefully to confirm its compliance. It is strongly recommended to choose suppliers’ systems with independent certifications, that have been extensively fire tested and is compliant to Broof(t4).

 

To understand more about school building flat roof estate compliance, book our online CPD seminar; Mitigating Fire Risk in Flat Roofing, contact Cassey Smith; Business Development Co-ordinator on c.smith@langey.co.uk or call 07591 954885.

 

For more on the services Langley provides for schools read our guide to Pro-active Flat Roof Asset Management for Schools and Academies. This can be found by visiting: www.langley.co.uk/technical-downloads.

New Elgin primary school in Moray, Scotland, has had a Sarnafil HD system installed to meet their need for a new high-quality flat roof refurbishment.

With previous roof re-coverings not up to scratch, the school needed a system to improve the building’s thermal performance, save energy and improve robustness – providing a solution tough enough to mitigate damage caused by vandalism attacks experienced at the school.

By combining the thickest single ply membrane available – 2mm – and the most robust insulation board – SarnaTherm HD – the Sarnafil HD system offered a resilient and well-insulated solution. Plus, with the 2mm membrane outperforming all other membranes according to puncture test data, the system guarantees a long-lasting roof.

Moray Council specified Sarnafil HD for the 2500m2 roof after having previously used Sika Sarnafil products for numerous other school and council properties with great success.

 

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The main challenge of the refurbishment was installing the roof during term time in an operational school. However, all required health and safety measures were executed by principal contractor, Morrison Construction, ensuring the safety of those working onsite as well as staff, pupils and visitors.

Roofing sub-contractor A & B Buchan Ltd, a Sika Sarnafil Registered Contractor, was tasked with the installation. Despite the thicker HD membrane specified, their thirty years of experience with Sarnafil products meant the system was installed seamlessly by their expertly trained team.

Senior Technical Advisor at Sika, John Love said: “Despite the challenges of the project, regular site visits carried out by Sika and the excellent communication maintained between Morrison Construction and A & B Buchan Ltd meant the installation ran smoothly and was completed to the client’s satisfaction. This project is also a prime example of the many benefits of Sarnafil HD and we are thrilled with the final result in terms of durability and longevity.”

Moray Council said: “The design had measures of complexity, however, our Environmental Services Property section worked with Sika throughout the process to combat any issues and were completely satisfied that the end result is an efficient, effective and long-term flat roof construction.”

With a combination of the hard-wearing Sarnafil HD and the use of SarnaLite roof lights and SikaLastic liquid polyurethane to finish the installation, the durable roof is now protected for years to come. And with a twenty-year Sarnafil Plus Extended Product and Installation Guarantee, the school has gained complete peace of mind.

 

www.sarnafil.co.uk

Following a detailed assessment of the Diocese of Norwich Education and Academies Trust’s education facilities, Langley Waterproofing Systems Ltd identified a need to refurbish the roof at Sporle Primary Academy, King’s Lynn, urgently. The team replaced the facility’s existing roof with Langley’s TA-25 Reinforced Bituminous Membrane system, providing a robust, long-lasting solution.

 As an approved and trusted supplier under the LHC framework for Flat Roofing and Associated Works (FR2), Langley was appointed by the Diocese of Norwich Education and Academies Trust to conduct extensive and detailed condition surveys of the roofs at five of its premises.

This included a comprehensive strategy to prioritise facilities with the worst damage to their roofs and outline how to fix the failures that had been identified. This was key to ensure compliance to FR2, which looks to guarantee that work completed on public sector buildings, such as those owned by the Trust, is carefully considered and of a high standard.

“The works Langley has completed so far for the Diocese of Norwich Education and Academies Trust is testament to the company’s high standard of work. Under FR2, it is vital that companies take a considered approach to every project and strive to achieve the best for our customers – Langley was a clear frontrunner,” explained Ben Jones, Senior Client Support Manager at LHC. “The quality of Langley’s products and the service it offers is exceptional, and it is clear the company carefully evaluates the economic, social and environmental impact of the work that it recommends.

 

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“This is key for public sector clients, as they don’t always have a large budget. That is why the FR2 framework is so valuable – as it sets rates for the design, supply and installation of flat roofs, to help customers achieve best value; and it provides an assurance of high quality work, which will minimise future problems and additional repair costs.”

On completion of the condition surveys, Langley prioritised work to Sporle Primary Academy, which was experiencing severe water ingress issues. Ponding water had also occurred on the roof, due to previously insufficient falls towards the roof outlets. The roof lights originally installed onto the roof had also failed, leading water to leak into the building.

Despite previous repair attempts, the severity of the water ingress, as well as the age of the original system, meant the roof needed to be completely replaced. Langley specified its TA-25 Reinforced Bituminous Membrane system – a high performance SBS elastomeric membrane warm roof system for flat or sloping roofs. Langley also added tapered insulation, which created greater falls towards the roof outlets to ensure that water would run off the roof more efficiently. The TA-25 comes with a comprehensive 25 year guarantee, providing assurance that the new roof will be a long lasting, durable solution.

Howard Nelson, Chief Operating Officer at the Diocese of Norwich Education and Academies Trust said: “We are incredibly pleased with the work that Langley has completed across five of our academies, including Sporle Primary Academy. Through the FR2 framework, we had the reassurance that Langley could not only repair the roofs, but also that the work would be of a high standard. Throughout each project, Langley kept us up-to-date with detailed reports and images of the work as it progressed.

For the safety of students and staff, the Academy was required to be closed during the refurbishment work. As a result, the Langley team, along with Langley Approved Contractor Cambridge Flat Roofing, had to adhere to tight schedules and ensure that work was completed within the Academy’s six-week summer break. It was also vital that the work was sympathetically completed, avoiding any damage to the rest of the structure.

Howard concluded that “the team was very accommodating and made sure each project was completed quickly and to a high standard – I have no doubt that, if we were to ever experience roof failures again, we would call on Langley.”

Including Sporle Primary Academy, Langley has now been entrusted with five premises under the Diocese of Norwich Education and Academies Trust.

For more information about Langley Waterproofing Systems, please visit https://www.langley.co.uk/.

Kingspan Kooltherm K7 and K107 Pitched Roof Board have been installed as part of a major refurbishment project, transforming a former Victorian mill into CAT B office space for Manchester Metropolitan University.

6 Great Marlborough Street forms part of Manchester’s rich industrial heritage and sits within Little Ireland, the earliest area of Irish settlement within the city. The sensitive restoration plans make a feature of the historic building fabric, exposing the original brickwork and beams internally, whilst incorporating more contemporary elements such as building services and modern windows.

 

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The design team prepared the fit-out using the Royal Institute of Chartered Surveyor’s SKA Rating environmental assessment method – targeting a Silver rating certificate. As part of this process, they identified an opportunity to upgrade the thermal performance of the poorly insulated pitched roof. To minimise heat loss through the roof, a construction combining Kingspan Kooltherm K7 and K107 Pitched Roof Board was installed.

Kingspan Kooltherm K7 and K107 Pitched Roof Board can achieve thermal conductivities as low as 0.020 W/m·K and 0.018 W/m·K, respectively. In combination with their low emissivity foil facing, this makes them amongst the most thermally efficient pitched roof insulation materials in common use.

As the original roof slates have been retained, the boards were cut to size by hand and fitted between and below the existing roof rafters from inside the building. This premium specification allowed the target U-value to be met with the slimmest possible construction – maximising floor to ceiling heights in the top storey spaces in the 5-floor building.

Kingspan Kooltherm K7 and K107 Pitched Roof Board are produced under an integrated management system which is certified to the highest standards including ISO 9001: 2015 (Quality), ISO 14001: 2015 (Environmental), BS OHSAS 18001: 2007 (Health and Safety) and ISO 50001: 2011 (Energy). Their insulation core is manufactured with a blowing agent that has zero Ozone Depletion Potential (ODP) and low Global Warming Potential (GWP).

 

www.kingspaninsulation.co.uk