External Wall Insulation or Rainscreen Cladding? What are the differences?

northfield-high-rise-refurbishment- external-wall-insulation

Following the horrific events at Grenfell Tower, questions have been asked regarding the performance of externally-insulated systems and cladding systems have subsequently been removed from a number of high-rise residences. In view of the government’s drive to deliver more thermally efficient buildings, a significant number of properties have been retrofitted with additional insulation and cladding over the last 5 years. It is therefore important to distinguish between the two systems that will have been most widely used in these refurbishment works, i.e. rainscreen cladding and external wall insulation.

Rainscreen cladding systems

As the name suggests, rainscreen systems are designed to protect the building from the weather. Rainscreen cladding systems will typically comprise a decorative outer panel (e.g. aluminium composite material (ACM), ceramic, fibre cement, glass) which is connected to the structure of the building with a lightweight metal frame. The framework is used to create a cavity so that the insulation can be fixed to the wall, whilst still allowing an air gap to exist between the outer panel and the insulation. This air gap is required for ventilation and drainage. The nature of these systems is such that the external panel and different components within the system can be procured independently of each other to form a hybrid solution.

External wall insulation (EWI) systems

External wall insulation (EWI) systems typically comprise an insulation board that is adhered (and often mechanically fixed) to the outside face of the wall. The insulation board is encapsulated with two layers of cementitious render either side of a fibreglass mesh reinforcement. A further coat of cementitious render is then applied to achieve the finished appearance. Each layer is applied directly to the surface of the previously installed layer, without the introduction of any cavities.

To be eligible for use in funded schemes (e.g. ECO2T, CERT, CESP), EWI systems must be accredited by third party bodies such as the British Board of Agrément (BBA). Accreditation requires extensive testing into the system’s performance in respect of combustibility, structural integrity, water absorption and vapour permeability inter alia. This level of system testing reduces the likelihood of hybrid systems being accepted for use, as these tests form the basis of the third party’s attestation of compliance with the relevant building regulations.

To comply with building regulations pertaining to fire on high-rise residences, either the components of the system must be classed as non-combustible or the specific configuration must have been subjected to a full-scale fire test to prove the required response of the system in the event of a fire. EWI systems that are classified as non-combustible will comprise mineral wool insulation. However, full-scale fire tests have indicated that other insulations, including expanded polystyrene (EPS), can also be used when encapsulated in A1 or A2 rated cementitious renders.

When contrasting EWI and rainscreen systems, there are fundamental differences in the materials used, the construction configuration and the system accreditation requirements. As such, it is important to consider the performance of EWI systems independently from the findings pertaining to rainscreen cladding systems.

By Simon Poë | Managing Director of Alumasc Facades

Introducing EWI Gutter from Alumasc Facades – Giving refurbishments the new build look

EWI-Gutter-MainAlumasc Facades have been a trusted manufacturer of External Wall Insulation systems for over 60 years and have now applied their knowledge of the building envelope to a brand new EWI Gutter Range.

EWI Gutter from Alumasc Facades, has been designed specifically to address the problem of cold bridging at eaves level whilst creating an aesthetically pleasing and cost effective alternative to standard verge trims on refurbishment projects.

As refurbishment of existing properties continues to trend, the new EWI Gutter system offers architects and home-owners a retrofit solution with a new build look. Gone are the days of rotting timber and brittle, sun-damaged PVC, Alumasc’s EWI Gutter presents a long-lasting, low maintenance alternative, manufactured in Aluminium to provide a clean, contemporary finish.

Box and Ogee are available as standard profiles, and with manufacturing taking place at Alumasc’s plant in the UK, bespoke profiles can easily be provided.

Bringing the benefits of Alumasc’s on-site technical knowledge and support, together with a network of Registered Installers, EWI Gutter is lightweight, quick and easy to install, with lifetime maintenance costs being far lower than those presented by high-maintenance alternatives. The product is supplied painted, in black, white or grey as standard, with additional colour matches available on request.

Technical Director for Alumasc Facades, Mark Gibbs, comments:

“As a trusted supplier of External Wall Insulation systems, we work on hundreds of projects that are subject to design restrictions inflicted by retrofit rainwater systems. Having developed our own system, to perfectly complement the quality finish of our facades, we have opened up a range of new options to architects and designers, which allow for a far more contemporary ‘newly built’ look.

“We are also aware that our colleagues see advantages in a one-source product offer. They already know Alumasc offer unrivalled products and technical support, so the addition of the EWI Gutter system further supports the whole process whilst also addressing ever-important budget considerations. It is widely acknowledged that Aluminium presents greater value for money over the lifetime of the product. When installed to Alumasc recommendations, the result is a long-lasting solution that can withstand the rigours of the British weather for just as long as the EWI .”

For more information, please call Alumasc Facades on (0) 3335 771 700.

http://www.alumascfacades.co.uk/products/external-wall-insulation/ewi-gutter-system/

LABC Registered Approval for 3 Alumasc Facades Systems

LABC External Wall Insulation

Alumasc Facades is pleased to announce that the Alumasc Ventilated System (AVS) has been awarded LABC & LABSS certificates. These AVS systems have been rigorously tested for key factors including:

  • Mechanical Resistance & Stability
  • Safety in case of Fire
  • Health, Hygiene and Environmental
  • Safety in Use
  • Durability serviceability and identification

Local authority building control (LABC) Registered Details is a one-off certification process proving compliance with building regulations and standards across England, Wales and Scotland. LABC & LABSS registration helps to ensure acceptance by all local authorities across England, Wales and Scotland whilst making the building control process more efficient.

Registered Alumasc Facades EWI Systems

The Alumasc Ventilated System (AVS) consists of back-ventilated external cladding which is mechanically fixed to either treated timber battens or galvanised rails which is designed for use in conjunction with timber framed substrates. The system includes a carrier board on which a render base coat is bonded.

Visit our website for more information on our render and external wall insulation systems.

Book a CPD for your organisation. Seminars include: External Wall InsulationAlumasc Ventilated System and Utilising External Wall Insulation on High Rise Buildings.

Swisslab revitalises Glasgow building

As part of the regeneration of Glasgow’s Shawlands area, Glasgow Housing Association (GHA) recently embarked upon the recent refurbishment of 1265 Pollokshaws Road, a block of maisonette homes located above a mixture of shops and a car park.

PollokshawsRoad3The four-storey building, constructed of “bison” precast concrete panelling in the 1960s, comprises a 50/50 split between GHA and private ownership. The project received ECO funding and the private homeowners also received grant-aid funding from the city council due to the non-standard construction of the building.

To address both thermal performance, and aesthetic appearance, main contractor, City Building Glasgow, engaged the services of expert EWI installer, AC Whyte.

Alumasc’s Swisslab EWI system was specified for the project because it is perfectly suited to overcladding existing properties. AC Whyte installed the system with a 60mm phenolic insulation and finished it with Silkolitt silicone render in 3 subtle pastel shades.

The challenging installation could only be overcome with a large degree of technical expertise from both Alumasc and AC Whyte who worked closely together to ensure a successful solution.

PollokshawsRoad_BEFOREFirstly, the precast concrete panel exterior and its various substrates meant that AC Whyte and the Alumasc technical team had to carefully consider the fixing type to ensure a robust fix. Secondly, the existing façade featured a series of timber frame panels under the windows. Drawing upon Swisslab’s versatility, AC Whyte and Alumasc were able to employ careful detailing methods and the use of expansion joints. This led to these panels being “designed out” resulting in a simpler monolithic appearance which is much fresher and modern.

Finally, the car parking area below the flats, was also one of the main causes of poor thermal performance, and this was also given the Swisslab treatment with its soffits treated to insulate the exposed floors of the first floor flats above.

Giving his seal of approval to the scheme, Eric Conquer, Asset Planning Manager at GHA, said:

“The refurbishment work completed by Alumasc and AC Whyte at Pollokshaws Road has made an enormous difference. Our customers are really happy with the way the building looks, and their homes are now much warmer.”

For more details call Barrie Robertson on 07720 883 693.

For information on Swisslab External Wall Insulation, click here.

Best Practice in the Thermal Upgrade of High Rise Buildings

Alumasc’s Technical Director Mark Gibbs explains what specifiers should be looking for in their chosen EWI system for high-rise and why safe installation is paramount.

blackfriars_main Why EWI?

Specification for the multi-storey application of External Wall Insulation is very different to that of low-rise projects, with health and safety procedures being a key consideration in the thermal upgrade of high-rise buildings.

EWI is a cost effective method of achieving the thermal and aesthetic upgrade of buildings. EWI has been used in the UK for the refurbishment of high rise projects for over 25 years. The solution is particularly effective for, although not limited to, high-rise social housing schemes of non-traditional or traditional type construction. Condensation, water ingress and the poor thermal performance of many of these blocks has been addressed by specifying EWI, providing a U-Value to comply with current Building Regulations.

EWI System Build-up for High-Rise 

To achieve the thermal requirements of the project, the appropriate type of EWI insulation board is mechanically and adhesively fixed to the substrate. A polymer modified reinforcing base coat, incorporating a fibreglass reinforcement mesh, is then applied. Once this has fully cured, there is a choice of finishes ranging from traditional dash or painted renders, to more modern through-coloured silicone renders.

riverbank1High-Rise, not High Risk

High-rise EWI specification is different to that of low rise because the insulation boards must be adhesively and mechanically fixed. Wind load calculations are essential and the edge zones, external corners and openings require increased mechanical fixings to accommodate higher wind loads. The calculations must always be conducted by Structural Engineering Consultants to ensure structural stability, required performance and system longevity.

Specified EWI systems must be officially accredited and approved for use in high-rise application. A large scale fire test or reaction to fire test is required for the system when used above 18m in height.

Installation Considerations

As well as through-the-wall square metre rates, there are additional detailing considerations compared to low-rise. These include parapet, lightening conductor, CCTV, external lights, robust window cill details, ground floor entrance areas etc.

It is critical that all the detailing is robust and installed as per specification. Once the wall access is removed any repairs are more difficult and costly to address than for low-rise projects.

Scaffold ties should be fixed in the most practical locations and protected scaffolding is recommended. Alternatively, mast climbers are an economical and faster track option for EWI install but offer less protection to newly installed work. Programming considerations should always allow for weather conditions.

Energy Efficiency

EWI is a cost-effective and energy efficient solution for high-rise blocks allowing for an aesthetic transformation of the building and the surrounding area. Improved thermal performance results in less fuel consumption and therefore less CO2 emissions leading to a typical saving of around 30% on tenants’ heating bills.

View the gallery of Alumasc’s high-rise projects.

Download Alumasc’s full High-Rise Brochure.

For more information on External Wall Insulation click here or please call us on 03335 771 700.

Award Winning Home calls on Alumasc Render Systems

bankhall_pr2An award winning Cheshire property has been refurbished using Render Systems from Alumasc. Owned by David and Margie Edwards, the magnificent Bankhall House was originally completed in 2008, to a traditional Georgian/Queen Ann architectural design, earning them the prestigious title of Daily Telegraph Best Traditional House in the UK for 2010.

Following some initial problems with the original render system, David Edwards embarked on a 4-month study of the render market, in search of a system that would complement and protect his beloved Bankhall.

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Following rigorous research into suitable products and approved contractors, David, brought in Alumasc Registered Installer Bruce Day of Cheshire Facades, who, according to David, “worked alongside Alumasc’s technical team to show passion above and beyond that of their competitors”.

bankhall_prpicDavid, Bruce, and the installation team, worked closely together in the investigation and resolution of the initial render problems, and specified Alumasc’s MR Polymer Render System with a decorative Silicone Render finish, as the solution.

Bruce Day has a well-established relationship with Alumasc and was confident that their products presented the right solution for Bankhall House. He comments:

“The traditional architecture at Bankhall presented a number of challenges with regard to application of the chosen render system. Intricacies in the stonework of the main house and also balustrades and plinths in the garden, demanded a robust system that could be easily applied. I have always found Alumasc systems easy to work with and in this case they also provided a perfect ‘cream’ colour match to the existing finish.”

David and Margie are thrillebankhall_pr3d with both the installation process and the result. David comments:

“Activity on site was reviewed daily by Cheshire Facades, and snagging was an integral part of my relationship with Bruce and his installers. Bruce insisted, “Our work must satisfy the customer – always”. I was also aware that render products have developed technically since the original installation, and Alumasc were able to offer all of the “cutting edge technology” required to give us the result we wanted. We feel like we’ve been given a new house.”

Alumasc Polymer and Silicone Render Systems are BBA Approved and fully warrantied. They are less susceptible to cracking and crazing than traditional plain render and are fully weather resistant whilst remaining vapour permeable.

For more information, click here or call Andy Gait on 07876 773064.

Stanton residents living in comfort thanks to Swistherm

Swistherm from Alumasc, has been installed on 25 park homes in Suffolk, in a bid to help tackle fuel poverty amongst the elderly residents.

parkhome1West Suffolk Council partnered with Alumasc’s Registered Installer Cornerstone Limited, to carry out the installation and improve the thermal efficiency of the homes at Shepherd’s Grove Park in Stanton, which were suffering from poorly insulated walls.

Cornerstone carried out all necessary adaptions and remedial works to prepare the properties for the insulation, given that these comprised a number of different park homes styles in various states of repair.

parkhome2Before the works began, initial pull-out tests were completed to determine the mechanical fixings and fixing patterns required. Alumasc’s Swistherm EWI system was then installed with premium grade EPS insulation and finished in Alumasc’s 1.5mm decorative silicone render, with the homeowners being given a choice of colours.

The new system has significantly improved the previously poorly insulated walls,  achieving a U-Value of 0.29 W/2mk, with the insulation also securing a 25 year insurance backed warranty. In addition, the decorative render coat has rejuvenated the properties, improving the overall aesthetics of the scheme.

parkhome3Cornerstone reports that homeowners are now benefitting from warmer and more thermally efficient properties, which has in turn significantly reduced their energy bills. The feedback from homeowners has been wholly positive, with numerous reports of greatly improved warmth and comfort.

For more information on Alumasc’s Swistherm system, click here

For more information on Alumasc’s silicone render, click here

Images and technical information courtesy of Cornerstone Limited

Alumasc Projects Highly Commended by INCA

Two outstanding refurbishment projects from Alumasc have been Highly Commended at this year’s INCA Awards.

Seagate_PRpicThe Awards represent the flagship event for the external wall insulation (EWI) industry designed to recognise and promote the quality of installation carried out by INCA members. Alumasc also received recognition for 4 additional projects which were all shortlisted in their respective categories.

The first of Alumasc’s projects to be Highly Commended was Seagate Court in the Domestic Refurbishment High Rise category. 

Seagate Court prior to refurb
Seagate Court prior to refurb

The project had been subject to rigorous weathering due to its coastal location in East Wittering – and it required a major external overhaul. 

2200 square metres of Swistherm EWI was installed to all exterior facades of the four blocks by Alumasc’s Registered Installer Primars Coatings of Middlesex. The system was insulated with a 90mm EPS and finished with Alumasc’s high performance silicone render.

See full project details here

OLYMPUS DIGITAL CAMERA

The second successful project was Pine Street in Durham, where over 100 properties had their appearance and energy performance completely transformed by the installation of Alumasc’s Swisslab EWI system.

Pine Street prior to refurb
Pine Street prior to refurb

Alumasc’s Registered Installer Westdale Services, installed the system at the scheme, with a 90mm grey EPS insulation and finished with a brick-effect render.

See full project details here

In addition to the recognition for its installations, Alumasc is proud to announce that Greg Curtis was also Highly Commended in the Outstanding Achievement Category for Training.

Picture 134With over 25 years’ industry experience, Greg has helped develop many careers in EWI installation. As a loyal member of the Alumasc on-site technical team, he always strives for the best possible install when coaching and training both approved and new installers.

Greg is an ambassador for quality workmanship and the high standards that INCA promotes to our industry.

For more information, visit INCA here.

Alumasc Ventilated System used on stunning Rutland extension

stamford1The new Alumasc Ventilated System has been used to create an unusual addition to a beautiful detached property in Oakham, Rutland.

The property, owned by Phil and Marianne Valiente, is of Canadian timber frame design, so it was therefore important that a system was found to complement the existing construction.

K&M Interiors of Melton Mowbray, were recommended to the owners for the external rendering. Being an Alumasc Registered Installer, K&M had extensive experience in the use of Alumasc systems. Following lengthy discussions about the benefits of the Ventilated System, it was specified for use on two separate extensions; one being a single storey to the rear of the property, accommodating a new kitchen/diner. The other, a two storey extension, would accommodate additional upstairs space and a reconfigured downstairs area, with living room, office and downstairs WC.

stamford2When used as part of a timber frame construction, the Alumasc Ventilated System is quick and easy to install, presenting a more efficient and sustainable alternative to traditional brick and block methods. It offers an engineered, stylish facade solution, designed to provide a fully ventilated cavity, which keeps the timber substrate moisture-free.

The project was finished in Alumasc’s Silkolitt 1.5mm silicone render in white and the system is also compatible with brick slip finishes.

Marianne Valiente comments:

“We were looking for a modern, high performance product that would incorporate the existing cedar shingles, whilst meeting our time constraints and the requirements of our local planning department.

“K&M talked us through the Alumasc system in great detail and we compared it to the alternatives. After receiving quotes for other solutions, we agreed that the Alumasc Ventilated System was vastly superior and offered us better guarantees. We had a lot of contact with the team from K&M, and found them to be professional, highly knowledgeable and very helpful.”

stamford3She concludes:

“K&M Interiors did a great job and we’re thrilled with how it looks. We’re now even considering having some of the brickwork at the front of the house rendered.”

The Alumasc Ventilated System has been rigorously tested, resulting in compliance with all UK building regulations (Scotland, Northern Ireland, England and Wales) and it became British Board of Agrément certified in May 2015. It also offers the option of use in off-site construction and adheres to the requirements and guidelines of both the NHBC and TRADA.

For more information please call Nigel Walters on 07720 883694.

Scotland to pilot £10m loan scheme

Scottish_thumbThe Scottish Government has made it possible for more people to make their homes warm and water-tight through a new £10 million fund.

The pilot scheme in Glasgow, Argyll and Bute and Perthshire will provide equity loans of up to £40,000 to home owners on low incomes to help them make essential repairs to leaking roofs and building structures – work which is often necessary before energy efficiency measures like EWI can be installed.

Housing Minister Kevin Stewart announced the pilot, commenting:

“Making sure everyone has access to a warm and affordable home is a priority for this Government which is why we have committed half a billion pounds over the next four years, meaning over £1 billion by 2021, to tackling fuel poverty and improving energy efficiency.

“We know leaking roofs and poor building structures can drive up energy bills and make them more difficult to heat, but for low income households they can often be too costly to repair. 

“This £10 million scheme will provide households with loans to carry out essential repair work and install energy efficiency improvements. 

“This will help us make homes warmer and easier to heat, with our record investment already resulting in two fifths of Scottish homes now being in the top three energy efficiency ratings – an increase of 71% since 2010.”

David Bookbinder, Director of the Glasgow and West of Scotland Forum of Housing Associations, said:

“It has always been clear that equity loan schemes offered by commercial companies won’t be attractive to owners. We therefore warmly welcome this Scottish Government pilot initiative which offers a really good deal for owners who have some equity in their property but can’t afford to pay regular loan interest.

“As well as facing the challenge of dealing with energy efficiency and other works in mixed tenure blocks, a number of community based housing associations would also like to work with their local council to tackle fully private tenements which are in poor condition and an increasing blight on the area. Widening the range of financial options for owners can only increase the chances of making this happen.

“GWSF very much hopes that the scheme can be expanded across Scotland after this pilot in three council areas.”

For more information on SEEP (Scotland’s Energy Efficiency Programme) Equity Loan Scheme , visit the Energy Savings Trust website.