External Wall Insulation - Regensw
RFR014
External Wall Insulation What is External Wall Insulation? External wall insulation (EWI) involves fixing a layer of insulation material to the wall, then covering it with a thin but reinforced, waterproof but ‘breathable’ type of render (plasterwork). Alternatively a timber structure might be attached to the wall, filled with insulation and finished off with timber or other cladding (a ‘ventilated rain-screen’ approach). With EWI the finish can be varied, but the choice will be influenced also by what thickness can be accommodated, which in turn is affected by the thermal performance of the particular insulation used. If the associated draught proofing relies on the outside face of the existing brick wall being ‘airtight’ then an initial thin covering of adhesive or render (known as ‘parging’) may be applied to the wall before the EWI is fixed. It is important to join this parging layer to windows and doors to ensure adequate draught proofing and vapour control before EWI is applied – tapes or sealants may be used. If windows are being replaced then the EWI should cover some of the window frame to improve thermal performance. A range of finishes, colours and textures are available. Acrylic and silicon finishes are popular and brick effect or brick slips are often used where there is planning issues or customer requirement.
What is the market for EWI installations? 6.6 million properties have solid walls in the UK and this represents 31% of the total housing stock. 48% of the 326,000 high rise flats in England have solid walls. Energy Saving Trust estimate that the number of EWI installations in 2008 to be 15,000-21,000. The Government is looking to push EWI installations so that carbon emissions from the existing housing stock falls. There target is for 88,500 installations per year by 2022. It would seem currently they are hoping decreases in installation cost will be the main driver for this increase. With increasing fuel prices we may well see more consumers (domestic and commercial) turning to EWI. Additionally upcoming legislation on rental properties to achieve a minimum of level D Energy Performance Certificate could stimulate the market further. It is possible customers can have EWI installed through the Green Deal. However currently it is looking unlikely EWI will meet the Golden Rule due to the cost of installation versus savings generated (on average £475 per year). It is possible for customers to top up any eligible Green Deal loan and Green Deal Providers may be able to bring costs down. Additionally the Energy Company Obligation (see document RFR11 on ECO), estimated to be £1.3b per year, will partially or fully fund EWI installations for eligible properties (hard to treat and/or low income area, etc). In terms of EWI applicators based in the south west, as of October 2012 INCA have 1 registered contractor and National Insulation Association have 5.
Does EWI have planning implications? Planning permission may be required through the Local Planning Authority (LPA). The LPAs main considerations are usually whether the overcladding constitutes a change in visual appearance, including
architectural details and effect on neighbouring properties. Properties in a conservation area will need to apply for planning permission. Local planning authorities can be found here.
What types of insulative board are used? There are a range of different insulative materials each with certain performance characteristic and benefits/disadvantages. The most commonly used material is EPS and, in particular EPS with graphite sometimes referred to as EPS+. Where the thickness of the EWI needs to be constricted and the walls are of an adequate strength then some of the more high performing materials are used. Table 1: Typical insulative materials
Material
Eco rating 1
Aerogel Polyurethane (PU) Polyisocyanurate (PIR) Phenolic foam (PF) Expanded polystyrene (EPS) Extruded polystyrene (XPS) Wood fibre (WF)
A A A+
Insulant thickness (mm) to achieve 0.25W/m2/k 2 50-55 75-145 80-105 75-95 115-160
Range of Thermal Conductivities (W/mK) 3 0.01 0.02-0.03 0.02 0.02 0.03-0.04
Typical cost per sqm4 £175 £24
E
95-140
0.02-0.03
-
-
145-225
0.03-0.06
£28
1. The environmental ratings of different types of insulation (with A+ being the best) have been taken from the latest assessments in BRE’s Green Guide to Specification. Using Life Cycle Assessment, the impacts associated with extraction, manufacture, transport and disposal – sometimes referred to as ‘embodied impacts’ – have been evaluated. The comparison between materials is on the basis of similar thermal resistance, rather than mass or volume. 2. U-values calculated based on 9” solid brick wall, internally applied insulation (with battens and/or air gap where appropriate) and 12.5mm plasterboard. Fixings and air movement accounted for in calculated figures. All thicknesses rounded to nearest 5mm. 3. Lower numbers indicate better thermal performance. The thermal conductivity ranges are the minimum and maximum obtained from the thermal conductivity values declared by UK manufacturers (or suppliers) and those given 4. These are very average figures and only an indicator as there are a number of factors which can effect price, we hope to have figures for all materials soon More information can be found in the Energy Saving Trust document CE71.
Does EWI affect damp issues? EWI generally keeps most parts of the wall warm, however attention should be paid to any remaining cold spots that may be left, such as below DPC level at the base of the wall or at the point where EWI changes to InternaI Wall Insulation (IWI). Ideally the wall should be insulated down to the ground or even into the ground at wall bases, and internal insulation should overlap with external where possible to reduce these localised cold spots. Most external wall insulation systems using ‘open cell type’ allow water vapour to escape through both the insulation material
and the microporous or fully ventilated weatherproof render or cladding. Less ‘vapour open’ insulations should be assessed for suitability by the installer. Ensuring adequate controllable house ventilation should always be part of any insulation improvement work.
What are the typical costs for installations Typical insulative material costs are mentioned in table 1, additional costs to consider are preparation and making good of any loose wall areas, scaffolding, removal of items (gutters, pipes, dishes, etc), extension of roofing, replacement of architectural features and reinforced areas for items hanging from finished wall.
Energy Saving Trust published typical EWI installation customer costs for 2009 in their Solid Wall Insulation Supply Chain Review document. The table below is from that document and separates cost estimates for insulation of a single property and for a project involving multiple properties, the latter taking economies of scale into account. In each case costs have been split into those covering EWI material and installation and the extra costs incurred in the majority of cases (scaffolding, preparatory work and making good, as outlined above). For most EWI projects the total customer costs given below will apply.
EWI - multiple properties 100+ EWI – multiple properties under 100 EWI – single property
Cost of EWI material and installation £4,800-6,000 Average £5,500 £5,600-8,500 Average £6,500 £7,600
Extra costs required for installation £1,500-4,000 Average £3,000 £2,000-5,000 Average £3,500 £3,000-7,000 Mid-point £5,000
Total costs £6,300-10,000 Average £8,500 £7,600-13,500 Average £10,000 £10,600-14,600 Mid-point £12,600
How do you start installing External Wall Insulation systems? If your company has basic construction experience and can apply external renders then you need only contact an EWI manufacturer and become an accredited applicator. This will mean you can install EWI with the manufacturer’s warranty and be supplied work by them. The applicator may require you either attend a training course or be trained on-site depending on level of experience. See table 2 for more information. There are formal qualifications available through further education colleges and private training organisations. The Level 2 NVQ Certificate in Insulation and Building Treatments – External Wall Insulation has been designed to enable individuals specialising in installing EWI to demonstrate competence. Information on this qualification can be found on the ABBE and Construction Skills websites. Currently the only college in the south west delivering the qualification is Weston College over 12 weeks at a cost of £675. However, we expect the number of outlets to increase and please contact the Ready for Retrofit team if you are interested in this qualification. Please note to be a registered Green Deal Installer you will need to comply with one of the four Common Miniminal Technical Competencies (CMTC) which include relevant NVQs and certified EWI manufacturer accreditation. For more information see guidance document RFR10 on Green Deal Installers.
Who are the EWI system manufacturers Table 2 contains information on some of the main EWI system manufacturers covering the south west. The manufacturers can be an important source of EWI work and you can be accredited to one or more. Training will either be done at a training centre or on-site if the level of knowledge is high enough. Important considerations when choosing a manufacturer are:
Types of insulative material supplied? o Certain applications require particular materials or customers may specify What accreditations do they have? o Look for British Board of Agrement, Insulated Render and Cladding Association, or National Insulation Association What warranties do they offer? o To install EWI as part of the Green Deal you will need to offer a 25 year warranty Where is the materials distribution centre? o The closer it is to your area of work the lower the risk What is their support setup? o How many support workers do they have in your area? What’s the cost of training and where is it carried out o Training normally lasts 1 day and costs range from free to £150 per person depending on number of delegates, some carry out training on site if the initial skill level is adequate Do they have a market reputation o Many EWI systems will tender for works and can drive business to your company Table 2: EWI manufacturers
Company
Regional contact
Head office Location
Knauf SAS
Unger Diffutherm SPS Envirowall Wetherby
Weber Structherm Permarock Parex Alsecco Alumasc
Training Max cost per delegate -
Max duration (days) -
Craig O’Donnell, 07739 446412 Laurence Hughes, 07557 980167 Chris Brookman, 07702 199120 Dan Macy, 07824 873987 Adrian Stanton, 07738 457512
St Helens
Cheltenham
Exeter
Exeter
£1501
1
Exeter
-
£500
3
Keignley
Cardiff
£100
1
Warrington
S. Wales
-
Nick Eaton, 07788 430685 Simon Haile, 07872 455999 Virginia Walker, 07980 723012 Peter Barker, 0776604554 Sam Holman, 07968 420384 Lee Carter, 07801 253798
Bedfordshire
-
01942 528269 Lesley -
W. Yorkshire
W. Yorkshire
-
-
Loughborough
Loughborough
£50
1
Warwickshire
Bristol
£0
½-1
Stoke on Trent
Stoke on Trent
£0
1
St Helens
St Helens
£150
2
-
1: 10% discount for 2 or more delegates Please note Sto, one of the biggest EWI manufacturers, are as of October 2012 not taking on new applicators.
External Wall Insulation What is External Wall Insulation? External wall insulation (EWI) involves fixing a layer of insulation material to the wall, then covering it with a thin but reinforced, waterproof but ‘breathable’ type of render (plasterwork). Alternatively a timber structure might be attached to the wall, filled with insulation and finished off with timber or other cladding (a ‘ventilated rain-screen’ approach). With EWI the finish can be varied, but the choice will be influenced also by what thickness can be accommodated, which in turn is affected by the thermal performance of the particular insulation used. If the associated draught proofing relies on the outside face of the existing brick wall being ‘airtight’ then an initial thin covering of adhesive or render (known as ‘parging’) may be applied to the wall before the EWI is fixed. It is important to join this parging layer to windows and doors to ensure adequate draught proofing and vapour control before EWI is applied – tapes or sealants may be used. If windows are being replaced then the EWI should cover some of the window frame to improve thermal performance. A range of finishes, colours and textures are available. Acrylic and silicon finishes are popular and brick effect or brick slips are often used where there is planning issues or customer requirement.
What is the market for EWI installations? 6.6 million properties have solid walls in the UK and this represents 31% of the total housing stock. 48% of the 326,000 high rise flats in England have solid walls. Energy Saving Trust estimate that the number of EWI installations in 2008 to be 15,000-21,000. The Government is looking to push EWI installations so that carbon emissions from the existing housing stock falls. There target is for 88,500 installations per year by 2022. It would seem currently they are hoping decreases in installation cost will be the main driver for this increase. With increasing fuel prices we may well see more consumers (domestic and commercial) turning to EWI. Additionally upcoming legislation on rental properties to achieve a minimum of level D Energy Performance Certificate could stimulate the market further. It is possible customers can have EWI installed through the Green Deal. However currently it is looking unlikely EWI will meet the Golden Rule due to the cost of installation versus savings generated (on average £475 per year). It is possible for customers to top up any eligible Green Deal loan and Green Deal Providers may be able to bring costs down. Additionally the Energy Company Obligation (see document RFR11 on ECO), estimated to be £1.3b per year, will partially or fully fund EWI installations for eligible properties (hard to treat and/or low income area, etc). In terms of EWI applicators based in the south west, as of October 2012 INCA have 1 registered contractor and National Insulation Association have 5.
Does EWI have planning implications? Planning permission may be required through the Local Planning Authority (LPA). The LPAs main considerations are usually whether the overcladding constitutes a change in visual appearance, including
architectural details and effect on neighbouring properties. Properties in a conservation area will need to apply for planning permission. Local planning authorities can be found here.
What types of insulative board are used? There are a range of different insulative materials each with certain performance characteristic and benefits/disadvantages. The most commonly used material is EPS and, in particular EPS with graphite sometimes referred to as EPS+. Where the thickness of the EWI needs to be constricted and the walls are of an adequate strength then some of the more high performing materials are used. Table 1: Typical insulative materials
Material
Eco rating 1
Aerogel Polyurethane (PU) Polyisocyanurate (PIR) Phenolic foam (PF) Expanded polystyrene (EPS) Extruded polystyrene (XPS) Wood fibre (WF)
A A A+
Insulant thickness (mm) to achieve 0.25W/m2/k 2 50-55 75-145 80-105 75-95 115-160
Range of Thermal Conductivities (W/mK) 3 0.01 0.02-0.03 0.02 0.02 0.03-0.04
Typical cost per sqm4 £175 £24
E
95-140
0.02-0.03
-
-
145-225
0.03-0.06
£28
1. The environmental ratings of different types of insulation (with A+ being the best) have been taken from the latest assessments in BRE’s Green Guide to Specification. Using Life Cycle Assessment, the impacts associated with extraction, manufacture, transport and disposal – sometimes referred to as ‘embodied impacts’ – have been evaluated. The comparison between materials is on the basis of similar thermal resistance, rather than mass or volume. 2. U-values calculated based on 9” solid brick wall, internally applied insulation (with battens and/or air gap where appropriate) and 12.5mm plasterboard. Fixings and air movement accounted for in calculated figures. All thicknesses rounded to nearest 5mm. 3. Lower numbers indicate better thermal performance. The thermal conductivity ranges are the minimum and maximum obtained from the thermal conductivity values declared by UK manufacturers (or suppliers) and those given 4. These are very average figures and only an indicator as there are a number of factors which can effect price, we hope to have figures for all materials soon More information can be found in the Energy Saving Trust document CE71.
Does EWI affect damp issues? EWI generally keeps most parts of the wall warm, however attention should be paid to any remaining cold spots that may be left, such as below DPC level at the base of the wall or at the point where EWI changes to InternaI Wall Insulation (IWI). Ideally the wall should be insulated down to the ground or even into the ground at wall bases, and internal insulation should overlap with external where possible to reduce these localised cold spots. Most external wall insulation systems using ‘open cell type’ allow water vapour to escape through both the insulation material
and the microporous or fully ventilated weatherproof render or cladding. Less ‘vapour open’ insulations should be assessed for suitability by the installer. Ensuring adequate controllable house ventilation should always be part of any insulation improvement work.
What are the typical costs for installations Typical insulative material costs are mentioned in table 1, additional costs to consider are preparation and making good of any loose wall areas, scaffolding, removal of items (gutters, pipes, dishes, etc), extension of roofing, replacement of architectural features and reinforced areas for items hanging from finished wall.
Energy Saving Trust published typical EWI installation customer costs for 2009 in their Solid Wall Insulation Supply Chain Review document. The table below is from that document and separates cost estimates for insulation of a single property and for a project involving multiple properties, the latter taking economies of scale into account. In each case costs have been split into those covering EWI material and installation and the extra costs incurred in the majority of cases (scaffolding, preparatory work and making good, as outlined above). For most EWI projects the total customer costs given below will apply.
EWI - multiple properties 100+ EWI – multiple properties under 100 EWI – single property
Cost of EWI material and installation £4,800-6,000 Average £5,500 £5,600-8,500 Average £6,500 £7,600
Extra costs required for installation £1,500-4,000 Average £3,000 £2,000-5,000 Average £3,500 £3,000-7,000 Mid-point £5,000
Total costs £6,300-10,000 Average £8,500 £7,600-13,500 Average £10,000 £10,600-14,600 Mid-point £12,600
How do you start installing External Wall Insulation systems? If your company has basic construction experience and can apply external renders then you need only contact an EWI manufacturer and become an accredited applicator. This will mean you can install EWI with the manufacturer’s warranty and be supplied work by them. The applicator may require you either attend a training course or be trained on-site depending on level of experience. See table 2 for more information. There are formal qualifications available through further education colleges and private training organisations. The Level 2 NVQ Certificate in Insulation and Building Treatments – External Wall Insulation has been designed to enable individuals specialising in installing EWI to demonstrate competence. Information on this qualification can be found on the ABBE and Construction Skills websites. Currently the only college in the south west delivering the qualification is Weston College over 12 weeks at a cost of £675. However, we expect the number of outlets to increase and please contact the Ready for Retrofit team if you are interested in this qualification. Please note to be a registered Green Deal Installer you will need to comply with one of the four Common Miniminal Technical Competencies (CMTC) which include relevant NVQs and certified EWI manufacturer accreditation. For more information see guidance document RFR10 on Green Deal Installers.
Who are the EWI system manufacturers Table 2 contains information on some of the main EWI system manufacturers covering the south west. The manufacturers can be an important source of EWI work and you can be accredited to one or more. Training will either be done at a training centre or on-site if the level of knowledge is high enough. Important considerations when choosing a manufacturer are:
Types of insulative material supplied? o Certain applications require particular materials or customers may specify What accreditations do they have? o Look for British Board of Agrement, Insulated Render and Cladding Association, or National Insulation Association What warranties do they offer? o To install EWI as part of the Green Deal you will need to offer a 25 year warranty Where is the materials distribution centre? o The closer it is to your area of work the lower the risk What is their support setup? o How many support workers do they have in your area? What’s the cost of training and where is it carried out o Training normally lasts 1 day and costs range from free to £150 per person depending on number of delegates, some carry out training on site if the initial skill level is adequate Do they have a market reputation o Many EWI systems will tender for works and can drive business to your company Table 2: EWI manufacturers
Company
Regional contact
Head office Location
Knauf SAS
Unger Diffutherm SPS Envirowall Wetherby
Weber Structherm Permarock Parex Alsecco Alumasc
Training Max cost per delegate -
Max duration (days) -
Craig O’Donnell, 07739 446412 Laurence Hughes, 07557 980167 Chris Brookman, 07702 199120 Dan Macy, 07824 873987 Adrian Stanton, 07738 457512
St Helens
Cheltenham
Exeter
Exeter
£1501
1
Exeter
-
£500
3
Keignley
Cardiff
£100
1
Warrington
S. Wales
-
Nick Eaton, 07788 430685 Simon Haile, 07872 455999 Virginia Walker, 07980 723012 Peter Barker, 0776604554 Sam Holman, 07968 420384 Lee Carter, 07801 253798
Bedfordshire
-
01942 528269 Lesley -
W. Yorkshire
W. Yorkshire
-
-
Loughborough
Loughborough
£50
1
Warwickshire
Bristol
£0
½-1
Stoke on Trent
Stoke on Trent
£0
1
St Helens
St Helens
£150
2
-
1: 10% discount for 2 or more delegates Please note Sto, one of the biggest EWI manufacturers, are as of October 2012 not taking on new applicators.
