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

Statement by Alumasc Facades – 19th June 2017

We are aware of an article in the Scottish newspaper “The Sunday Mail” dated 18th June which refers to a number of projects at West Dunbartonshire, Scotland. Alumasc is cited in this article as the supplier of the Alumasc Swisslab Grey EPS system on high-rise buildings. However, there are a number of inaccurate statements in the article with regard to Alumasc and we would therefore comment as follows:

The Alumasc Swisslab Grey EPS system was approved for use on buildings and compliant with Building (Scotland) Regulations both before and after the changes made to those Regulations in 2013.

The statements in the article that the panels were “sub-standard”, “had been deemed a potential fire hazard”, were “suddenly changed to ‘low risk'” and required an “exemption to building standards” are therefore wholly inaccurate.

The article claims that “the cladding used across the council area is called (Alumasc) Swisslab Grey EPS.” However, there are references to and photographs of high rise buildings that had systems that were supplied by others and not by Alumasc.

Indeed, the Alumasc external wall insulation (EWI) system supplied on behalf of West Dunbartonshire Council under this scheme was for low-rise properties only and no high-rise buildings were supplied by Alumasc.

The article also refers to the “Grenfell-style cladding” and implies misleadingly that the Alumasc EWI system used on the West Dunbartonshire scheme was similar to the rainscreen cladding system that was reportedly used at Grenfell Tower.

There were a number of significant differences between the two systems which the article does not comment on. The key differences include:

1. The Alumasc EWI system has been extensively tested and includes a non-combustible mineral render that encapsulates the EPS insulation. The Alumasc EWI system was not finished with the polyethylene cored aluminium composite material (ACM) panel that is widely reported to have clad the Grenfell Tower; and

2. The Alumasc EWI system was directly fixed to an existing masonry substrate. The article references that voids can “act as a chimney for flames”. However, there is no such void between the insulation and outer skin of the EWI system supplied by Alumasc to this scheme.

Finally, we would like to reassure our customers that the EWI system that we supplied to Turner Facilities Management was at all times safe and remains so.

We have specialised in the design and manufacture of EWI systems for over 25 years and safety issues have, and continue to be, a key consideration for us on all our projects across the UK. Our systems have been approved by the British Board of Agrément, including an attestation that Alumasc’s systems can meet the requirements of the building regulations pertaining to the spread of fire.

If any of our customers have any concerns or questions, please refer to our website (www.alumascfacades.com) or contact us on 01744 648435.”

Alumasc Dominate Manchester Skyline


8 outstanding high-rise refurbishment projects are now benefiting from EWI systems by Alumasc Facades. These innovative systems are helping to visually rejuvenate the area whilst providing improved thermal efficiency and comfort to hundreds of residents.

Magnolia Court, Sycamore Court & Mulberry Court

Mulberry Court

Alumasc refurbished 3 high-rise buildings with Salix Homes and Seddon Construction LTD: Magnolia Court, Sycamore Court and Mulberry Court – the latter winning an award for Regional Large-Scale Project of the Year at the Energy Efficiency Awards held in April. Credit for the award is shared between Seddon Construction LTD, Salix Homes and Alumasc Facades – and recognises the energy efficiency measures introduced by the Government following the Energy Act 2013. These measures help homeowners reduce their energy bills, tackle fuel poverty and reduce carbon emissions. These high-rise buildings were originally specified in White EPS but during the specification stage, Alumasc obtained a BBA Certificate for the more thermally efficient Grey EPS, so the more efficient insulation was utilised instead.

Delaney Heights & Adelphi Court

Working with The Guinness Partnership, another 2 blocks have been transformed and improved both thermally and aesthetically using Alumasc’s Swistherm Mineral Wool system. The £9 million project in Salford transformed a former student accommodation block into 119 affordable rent homes – including specially adapted apartments on the ground floor for those with disabilities.

Clifford Lamb Court

Clifford Lamb Court – Before and After

Northwards Housing Association called on Alumasc to work together to help tenants stay warm and save money on fuels bills at Clifford Lamb Court in Greater Manchester. External insulation and new windows were installed on the Blackley high-rise block so that tenants can make the most of a cutting-edge heat pump which gets heat from the earth’s core by pumping brine 150m into the ground before bringing it back up to use in the building through individual heat pumps in each property. It’s the first time that this kind of Heat Pump technology (using a shared ground array serving individual heat pumps) has ever been used in a multi-storey housing block. The energy produced by the pump alone has helped tenants to save on their heating bills, but by making these extra improvements, Clifford Lamb residents will be even better off as more heat will stay inside the building. In total, the improvements will save around 850 tonnes of carbon dioxide every year.

Grosvenor House & Ryecroft House

Alumasc’s Swisslab system was chosen by Ashton Pioneer Homes and installed by The Casey Group Ltd to reinstate the existing EWI system that had exceeded its life span on Grosvenor House and Ryecroft House in Ashton-under-Lyne. Balcony cladding systems were secured to the majority of balconies, providing protection to the structure whilst improving the overall appearance of the block.

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.

Call area technical manager Andy Gait on 07876 773 064 for information on EWI in the Manchester/North West area or to book a CPD.

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.

Alumasc revives Brandon House

A Bristol social housing scheme is benefitting from an extensive £5million refurbishment, which saw Swisslab and Swistherm from Alumasc as the chosen EWI systems.

brandon_completed 2Built in the 1960’s of concrete panel construction, Brandon House was experiencing problems with structural movement which had caused a catalogue of building defects. In addition, the scheme also suffered from poor insulation leading to condensation, mould and water ingress.

Bristol Council commissioned a programme of works, which included the installation of Alumasc’s Swisslab and Swistherm External Wall Insulation to around 90 flats within the block.

brandon_completedAlumasc’s Registered Installer Rateavon, installed the systems with 60mm phenolic and 110mm EPS insulation, to address the previous issues, improving thermal efficiency, reducing heating bills and extending the life of the building. The systems were specified partly due to the fact that the 60mm phenolic insulation would not encroach on the limited space down a number of narrow walkways – and in addition Rateavon have a long track record of working with Alumasc products, and their installation skill was required around a number of intricate concrete columns.

Brandon House prior to refurb
Brandon House prior to refurb

Swisslab is Alumasc’s market leading EWI system used for overcladding exisiting properties, whilst Swistherm eradicates cold bridging, condensation and mould growth. Both systems are BBA Approved, offering an effective life of over 30 years.

The systems were finished using Alumasc’s silicone render with matching clay and acrylic brick slips, in order to comply with planning requirements.

For more information on High Rise EWI, contact Lee Carter on 07801 253 798



Alumasc leads the way in High Rise refurbishment

Alumasc's Swistherm with Mineral Wool insulation as used at Matthias Court
Alumasc’s Swistherm EWI with Mineral Wool insulation as used at Matthias Court

As the building industry continues to embrace the benefits of External Wall Insulation systems, Alumasc is in the grip of a high rise boom that has seen the increased specification of EWI in multi-storey applications across the North West.

2014/15 saw 7 high rise projects completed in Manchester, and already in 2016, 8 new projects are in progress; 2 for The Guinness Partnership, 1 for Northwards Housing, 2 for Ashton Pioneer Homes and 3 for Salix Homes.

Alumasc follow a strict High Rise Policy that takes into account all of the issues presented by high rise specification. In addition Alumasc always use independent Structural Engineering Consultants to conduct specific calculations to ensure structural stability, required performance and system longevity.

Alumasc  systems are officially accredited and approved for use in high rise applications and can be used with a range of insulation types versatile enough to overcome any design or technical challenges such as those at Magnolia Court and Sycamore Court, two of the Salix Homes schemes in Manchester.

Main Contractors Seddons and Registered Alumasc Installers SERS, worked closely with the Alumasc technical team to install Swistherm EWI with 170mm White EPS insulation at Magnolia Court and 150mm Grey EPS at Sycamore Court. These systems provided the ideal solution in terms of price and were able to tackle a number of intricate design details presented by both projects.

Matthias Court_smallNow belonging to The Guinness Partnership, Matthias Court had been empty for over 5 years and is about to undergo a complete overhaul. Installed by Alumasc Registered Installer SERS, the new EWI system will be the most visual change to the building, whilst the 150mm Mineral Wool insulation will make it highly thermally efficient. Alumasc has also been heavily involved with the architects Arcus Consultants, providing high quality technical support throughout a number of challenges faced in terms of installation and materials.

Grosvenor House and Rycroft House in Ashton Under Lyme were experiencing issues with the 40mm PIR board installed in the early 1990s. Alumasc has worked closely with Ashton Pioneer Homes and Casey Group to provide a number of solutions, ensuring that all works will be carried out efficiently and at the convenience and consideration of the residents.

With a growing number of future high rise opportunities currently being discussed, Alumasc is now regarded as the UK’s leading high rise specialist.

You can look through some of our past High Rise Projects by clicking here.

For more information on External Wall Insulation please contact Alumasc on 01744 648 400 or email: facades@alumasc-exteriors.co.uk

NIA Calls on DECC to announce its intentions on ECO & GDHIF

PrintThe National Insulation Association (NIA) yesterday (Thursday 2nd July) called on ministers from the Department of Energy and Climate Change (DECC) to make announcements about their intentions for the Energy Company Obligation (ECO) when the scheme comes to an end in 2017, and the Green Deal Home Improvement Fund (GDHIF), before the Summer Recess on July 21, 2015.

As the NIA explains, recent figures published by DECC and OFGEM on ECO showed that the energy companies have already made significant progress towards their targets for ECO2 (April 2015 – end March 2017) , and that based on the installation rates for 2014/15, the target could be achieved one year early in the first quarter of 2016.

This, the Association told Roofzine, is reflected in the major slow down in recent ECO activity, where just 29,000 measures were installed in April 2015 – a two-year low – compared to 51,000 measures in March 2015 and 58,000 in April 2014.

The NIA points out that in addition to this, the GDHIF – which was designed to compensate for the shortfall in ECO activity following Government cuts to the scheme in 2014, is also on hold whilst the industry awaits decisions from ministers.

The NIA says the combined effect of these two factors has resulted in a collapse in insulation activity which it says is “harmful to householders and the industry alike”.

Neil Marshall, chief executive of the NIA, said: “We would like DECC ministers to confirm that there will be an ECO post 2017, the broad shape of it and when they are likely to publish detailed proposals, and we would like them to give some indication of what they are intending for GDHIF and whether there will be any further releases of funding in the short term.”

This news follows the publication of the Committee on Climate Change’s (CCC) annual progress report, which highlighted that all main insulation measures are behind the required trajectory to achieve the UK’s carbon reduction targets – which in the case of solid wall insulation, the NIA points out, is some 500,000 behind trajectory.

The NIA also explained that the CCC recommended to Government that urgent decisions were needed on the future of ECO post 2017 to provide some assurance to the supply chain.

Swisslab chosen for Riverbank and Newbank Towers

RiverbankMainRiverbank and Newbank Towers in Salford, are two high-rise residential tower blocks owned and maintained by award-winning housing provider Salix Homes.  Built in the 1960s, both 16-storey tower blocks are identical in their face brick construction.

As part of the ongoing upgrade of its high-rise properties, Salix Homes embarked on a £6.6m improvement programme of both blocks, bringing them up to the Government’s Decent Homes standard.

3000m2 of Alumasc’s industry-proven Swisslab EWI was installed by BLD Construction (Facades) Ltd using 60mm Phenolic Insulation and finished with a combination of traditional clay brick slips to the lower floors – chosen for their high levels of impact resistance – with the remaining floors completed using silicone render, specified for its lightweight properties which minimise the structural impact of the system.

Alumasc’s technical team worked closely with the Rainscreen Manufacturer and the Project Architect to accommodate the inclusion of rainscreen cladding between the windows.

To ensure the interfacing detail between the EWI and the rainscreen panels was not susceptible to water ingress, the EWI was continued behind the rainscreen system with Alumasc’s hydrophobic scrim adhesive used to provide a waterproof seal around the brackets of the rainscreen  system. This detail provides continuity to the  thermal performance and eliminates cold bridging.

Commenting on the project, BLD Director, Bruce Day, said: “We have a successful track record of using Alumasc products on many high rise projects.

Alumasc EWI systems deliver really impressive results when it comes to improving energy efficiency. Swisslab was specified for this refurbishment due to its requirement of only 60mm phenolic insulation to achieve the required U target.”

Residents of Riverbank and Newbank Towers now enjoy warmer homes and lower energy bills with an achieved U value reduction from 1.47W/m2k to 0.26W/m2k.

Alumasc EWI systems are BBA approved, fully warranted and are available with a range of design and specification options, across many building types.

For more information, please visit www.alumascfacades.co.uk, call +44 (0) 3335 771 700 or email facades@alumasc-exteriors.co.uk

INCA 2014 Awards – The External Wall Insulation Showcase

INCA Banner


Blackfriars Court External Wall InsulationThere are now just under two weeks until the INCA 2014 Awards Dinner on Thursday 16th October at the Sheraton Park Lane Hotel in London’s Mayfair.

The awards showcase the very best in innovation and excellence of UK External Wall Insulation (EWI) projects over the past 12 months. This year Alumasc is delighted to have five shortlisted projects for the Swisslab EWI System.

Domestic Refurbishment – High Rise:

Project    Alumasc Registered Installer
Black Friar Court, Salford    BLD Construction (Facades) Ltd
Sunningdale, Wirral    BLD Construction (Facades) Ltd

Domestic Refurbishment – Low Rise:

Project    Alumasc Registered Installer
Elm Grove Flats, Newcastle    Sykes Specialist Contracting Ltd
The Green, Essex    Aran Services Ltd
South Greenfield, Glasgow    Volker Laser Ltd

Everyone at Alumasc is looking forward to the event, where there will be two Alumasc-hosted tables. It would be an incredible achievement to collect more awards for the second year running, although Alumasc are thrilled to be shortlisted for five categories – this is an achievement in itself!

Last year Alumasc won the prestigious Project of the Year 2013 Award with their Boxtree Tree Lane Project, an outstanding new residential development in Harrow.

The champagne reception and 3-course dinner offer an excellent networking opportunity and the INCA 2014 Awards, to be presented by former England cricket player Darren Gough, are a fantastic platform to showcase how External Wall Insulation is improving the energy efficiency of homes and business across the UK.

If you would like any further information regarding Alumasc External Wall Insulation and Render Systems, call (0) 3335 771 700or email facades@alumasc-exteriors.co.uk

Northfield House benefits from External Wall Insulation

northfield-high-rise-refurbishment- external-wall-insulationResidents in a Bristol social housing high-rise tower block are benefitting from warmer and more attractive homes, thanks to a combination of two tried and tested External Wall Insulation (EWI) systems from Alumasc.

Owned by Bristol City Council, Northfield House is an 18-storey block of 99 flats, surrounded by a complex of three lower-rise blocks totalling 60 flats. As part of a programme of improvements for all of the tower blocks in the city, the council instigated the £3.5m refurbishment of the blocks to address problems such as poor thermal performance, condensation, mould growth, water ingress, structural movement and crumbling concrete.

These had been caused in part, by the original methods and materials used to construct the buildings which included reinforced concrete frames, concrete flat slab roofs and cavity brickwork.


As a specialist in the provision of External Wall Insulation solutions for high rise buildings, Alumasc was able to offer a combination of two External Wall Insulation systems to improve energy efficiency at Northfield House. This met the need to use a system with high impact resistance at ground floor level, which wasn’t a necessity on the higher floors. Alumasc’s Swisslab External Wall Insulation system was ideal and was installed with a traditional, clay brick slip finish. On the remaining 17 floors, Swisslab External Wall Insulation system finished with acrylic brick slips was more suitable, being a lightweight solution which minimises the structural impact of the system.

Both systems are BBA approved, fully warranted and are available with a range of design and specification options, across many building types.


Other than the obvious requirement to improve thermal performance, another important challenge of the scheme was to colour-match the brick slips with the existing brick finish.

Lee Carter, South-West area manager for Alumasc, explains:

“To meet the requirements of the planning permission, we had to ensure that the new materials were a perfect match to the original exterior of the building in terms of colour. This meant matching the clay brick slips to the original substrate, and then matching the acrylic brick slips to the clay ones. The completed facade meets the planning conditions fully, with all material colours successfully matched.”


Over 4,000m2 of Alumasc external wall insulation was applied to Northfield House over a 10-month period by Alumasc registered installer Rateavon Ltd. As a result, U-values were reduced to 0.29W/(m2k) from 1.75W/(m2k) signifying greatly improved energy efficiency.

Commenting on the finished project, Danielle Mills, assistant quantity surveyor at Rateavon Ltd, said:

“The improved thermal performance of these blocks has reduced carbon emissions and heat loss. Residents’ living conditions have improved and their heating bills are now significantly lower. The blocks have retained their original appearance and problems such as damp, condensation and water ingress have been eradicated, reducing future maintenance costs.”

For more information on Alumasc External Wall Insulation or technical advice, call Alumasc Facade Systems on 03335 771 700.

Alternatively email: facades@alumasc-exteriors.co.uk