Insulation & Membranes
273 sources in the library on insulation & membranes. Each one says what the document covers and what it is good for. Name a source to see which document it is and where to read it. One at a time. Page 4 of 7.
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HomeOwners Alliance
Costed menu of efficiency measures. EPC £60 to £120 by property size. Loft insulation about £900 for a three bedroom semi, £1,100 detached, £1,200 detached bungalow per Energy Saving Trust, needing between 12cm and 30cm of thickness in most homes. PVC windows about £4,250 for a typical semi, roughly £325 per window, against about £15,000 for hardwood, roughly £1,500 per timber sash, with double glazing saving around £95 a year and requiring a FENSA accredited installer because building regulations apply to any window replacement. Cavity wall insulation about £22 to £26 per m2 for polyurethane foam or £13 to £18 per m2 for glass wool, averaging £725 for a detached house and £370 for a mid terrace. Internal wall insulation about £7,500 for a three bedroom semi saving around £210 a year, at a cost of about 10cm of lost floor depth. External wall insulation around £100 per m2, from £8,000 for a small flat to £22,000 for a large detached house. Solid concrete floor insulation £950 to £2,200 per room; suspended timber floor insulation £300 to £750 per room, saving about £50 a year or up to £85 in a detached house. Air source heat pump £3,000 to £18,000, ground source £13,000 to £35,000. Solar panels £2,500 to £8,000, with OVO estimating a 3.5kW array in southern England returns around £300 in year one.
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HomeOwners Alliance
The spray foam roof insulation problem set out with numbers. The Property Care Association estimates as many as 250,000 UK homes have spray foam in the loft, after roughly 30 years on the market and a decade of grant driven growth. Lenders may decline or downvalue a property with it. A specialist surveyor's inspection of the roof, structure and paperwork costs £500 to £700. Removal runs about £40 per m2 per Checkatrade, before skips and disposal; a reader case is quoted where removal of open cell foam was priced at £17,000 against an original £12,000 installation. Warns about rogue removal firms and states the code expectation of a cooling off period of at least 14 days during which no install or removal should take place.
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Leeds Beckett University
Two new European Standards for measuring aggregate heat loss from housing were published in 2024 and adopted in 34 countries, led by Professor David Johnston at Leeds Beckett with Professor Richard Fitton at the University of Salford. The standards are built on the Coheating Test developed at Leeds Beckett and, crucially, apply to new and existing real homes rather than laboratory test cells, so the thermal performance of housing can be measured and compared consistently across countries. The work took a decade. This is the standardisation behind the EN 17887 series used by Salford's Energy House Labs.
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Leeds Beckett University, Centre for the Built Environment
Tests the industry rule of thumb that background infiltration equals the blower-door result divided by twenty (n50/20, or q50/20 in the UK). Background ventilation rates in four new-build UK dwellings were measured directly by tracer-gas decay and compared with the pressurisation method using the conventional divide-by-twenty rule and Sherman's modified rule which accounts for building-related factors. The conventional rule over-estimated the air change rate in two dwellings and under-estimated it in the other two; the modified rule matched in two and significantly under-estimated in the other two. The conclusion is that the rule of thumb can produce significant errors in estimating infiltration, which in turn corrupts predicted in-use energy and CO2 emissions and can lead to ventilation strategies giving either unacceptable indoor air quality or unnecessary energy use, and that appropriate UK climate and building correction factors have yet to be devised. Johnston and Stafford, Indoor and Built Environment, 2016.
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Leeds Beckett University, Leeds Sustainability Institute
88 side-by-side fan pressurisation and low-pressure pulse airtightness measurements in existing dwellings of differing age, size, form and construction. Results: across the sample the mean airtightness reported by the two methods differed by only 2 per cent, but for individual homes the difference ranged from minus 84 per cent to plus 67 per cent, so the two tests can give wildly different answers on any one house even though they agree on average. Regulatory context stated: UK Building Regulations set a maximum airtightness of 8 m3/m2/h at 50 Pa for new dwellings, reducing to 5 m3/m2/h at 50 Pa or less in 2025 with the Future Homes and Buildings Standard; compliance is demonstrated by fan pressurisation or the newer low-pressure pulse test as set out in CIBSE TM23:2022. There is no maximum airtightness requirement when refurbishing an existing dwelling, though both methods are being used to inform retrofit, and existing homes have more varied and complex leakage paths than new build.
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Leeds Beckett University, Leeds Sustainability Institute
The research that changed Building Regulations on party walls. Leeds Sustainability Institute produced the empirical evidence that the cavity between party walls separating adjoining properties was responsible for a significant, previously unrecognised, heat loss, and that this bypass accounted for part of the discrepancy between predicted and measured heat loss in new dwellings. That heat loss mechanism is now formally recognised and developers must insulate walls between adjoining properties; previously heat could escape through and between party walls to the external environment. Context given: energy consumption in homes is responsible for around 15 per cent of UK carbon emissions. Underpinning paper: Lowe, Wingfield, Bell and Bell (2007), Evidence for heat losses via party wall cavities in masonry construction, Building Services Engineering Research and Technology 28(2), 161-181.
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Leeds Beckett University, Leeds Sustainability Institute
37 pressurisation and co-pressurisation tests on attached UK homes, measuring how much of the measured leakage is actually air moving between neighbouring dwellings rather than to outside. On average 21 per cent of the air leakage measured by a fan pressurisation test was inter-dwelling rather than inside-to-outside, meaning attached homes are more airtight than the test says. Consequences: not accounting for this risks under-ventilation and misclassifying homes as suitable for natural ventilation. When the measured airtightness replaced the EPC default for 11 case study homes the energy efficiency rating improved, showing EPC default airtightness values were over-estimating air leakage, and using the co-pressurisation value gained a further rating point; the improvements equated to reductions of 5 per cent in predicted annual carbon emissions, 8 per cent in space heating demand and 3 per cent in fuel bills. The paper concludes the elevated pressures of the test itself create leakage paths not present in normal use, which affects the accuracy of fan pressurisation in attached homes and its use for regulatory compliance, ventilation decisions and energy models.
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Leeds Beckett University, Leeds Sustainability Institute
Coheating test results from 25 new build dwellings built to Part L1A 2006 or better, the study that put a number on the fabric performance gap. The mean measured whole building U-value was just over 1.6 times greater than predicted, and for individual dwellings the gap between measured and predicted fabric performance could exceed 100 per cent, varying with dwelling form and construction type. Context: dwellings account for just under 30 per cent of the UK's total CO2 emissions, against a national target of an 80 per cent cut by 2050 on 1990 levels; around 80 to 85 per cent of the dwellings that will be in use in 2050 already exist. The practical implication for a homeowner is that a design SAP figure or an EPC is a prediction, not a measurement, and a real house can lose over half as much heat again as the paperwork says.
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Leeds Beckett University, Leeds Sustainability Institute
Measured the improvement from insulating a suspended timber ground floor two different ways and found the answer depends on the method. Aggregate whole-house measurement gave a U-value improvement of 0.55 W/m2K; disaggregated spot heat flux density measurements on the floor gave 0.89 W/m2K for the same retrofit. The conclusion is that disaggregated spot measurements may over-estimate the benefit of fabric retrofits and that aggregate methods are the more appropriate evaluation tool, which is directly relevant to any quoted saving derived from a spot heat flux reading. The paper also concludes that Energy Performance Certificates are unlikely to give a reliable estimate of energy savings because they rely on default assumptions for fabric U-values and ventilation rates, with consequences both for policy evaluation and for householders who may be excluded from financial support on the strength of an EPC figure.
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Leeds Beckett University, Leeds Sustainability Institute
Eight brick cores 100mm in diameter were taken from the outer leaf of solid walled homes across the UK (sites including Bedford, London and Loughborough) and lab tested, then modelled as a 110mm outer brick, 10mm air/mortar gap, 110mm inner brick, 10mm gypsum plaster wall. Results: modelled U-values of the uninsulated solid walls ranged from 1.6 to 2.6 W/m2K with an average of 2.1 W/m2K, against CIBSE Guide A book values averaging 1.7 W/m2K and ranging 1.4 to 2.0 W/m2K, so real bricks lost noticeably more heat than the standard assumption. EPCs assume a single default solid wall U-value of 1.7 W/m2K. Six of the eight homes carried surface condensation risks. Simulated moisture content of the inner brickwork varied between 0.1 and 5.8 per cent, meaning some bricks are at far higher risk of moisture accumulation than others, which is why an identical insulation detail can succeed in one house and fail in another.
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Leeds Beckett University, Leeds Sustainability Institute
Field trials plus thermal modelling (Brooke-Peat and Glew, 2021) showing that insulating one house internally can push a damp problem next door. Adding IWI reduces heat transfer from the room into the external wall, so the external wall behind the insulation becomes colder than the neighbour's uninsulated wall; heat then flows towards the colder side, and surface temperatures fall not only behind the insulation but also in the adjacent dwelling around the party wall junction, raising the risk of mould growth and surface condensation in a neighbouring property that has had no work done. The paper notes the legal as well as health implications, and that standard thermal modelling conventions do not cover thermally asymmetric party wall junctions, so the modelling had to split heat flow and surface temperature for each dwelling separately, using linear thermal transmittance (psi-value) and temperature factor (fRsi). Context figures: roughly 10 per cent of UK households are in fuel poverty, rising to 16 per cent of households in uninsulated solid walled homes, and only 7 per cent of ECO measures have been solid wall insulation.
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Leeds Beckett University, Leeds Sustainability Institute
The method statement for the coheating test, which is how whole-house heat loss is actually measured rather than modelled. The dwelling is left unoccupied and heated electrically by portable point heaters to a mean elevated internal temperature, typically 25 C, held over a number of days, with data collected 24 hours a day; a test typically runs for 1 to 4 weeks once the dwelling is heat saturated. Daily heat input in Watts is plotted against the temperature difference between inside and outside, and the slope of that plot gives the raw uncorrected heat loss coefficient in W/K, which combines fabric heat loss and background ventilation loss. It is a quasi-steady state aggregate method, one of only a few capable of measuring whole dwelling heat loss in situ (the alternative named is the PSTAR method), and it has existed since the 1970s. Practical cautions given: solar radiation absorbed one day may not be re-emitted until the next, and in a very airtight dwelling the ventilation rate can be so low that it takes 2 to 3 days for all the air in the dwelling to be exchanged.
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Leeds Beckett University, Leeds Sustainability Institute (for BEIS)
Measured comparison of thin internal wall insulation (TIWI) against conventional internal wall insulation on solid brick walls, using coheating tests for the whole-house heat transfer coefficient in W/K plus dynamic simulation for bills. Findings with numbers: TIWI is only 20 to 30 per cent of the thickness of conventional IWI and gives U-values between 0.8 and 1.4 W/m2K on solid brick, yet delivers between 40 and 70 per cent of the fuel bill savings conventional IWI achieves. Diminishing returns are stark: conventional IWI was in some cases four times thicker than TIWI yet gave only 22 per cent more benefit. TIWI can take up to a third less floor area than conventional IWI, and TIWI products needing no decoration were the cheapest to install, though some require multiple visits which raises labour cost. Moisture caution stated plainly: neither IWI nor TIWI removes moisture risk, both can increase condensation risk on adjacent surfaces and in neighbouring homes, and both must be fitted to walls in good repair. Policy context: solid wall insulation appears in only around 7 per cent of ECO retrofits and IWI accounts for less than 1 per cent of ECO measures; the report argues the 0.3 W/m2K target for solid walls deters uptake, noting cavity wall retrofits are allowed 0.55 W/m2K.
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NHS
Health background for anyone disturbing asbestos in a renovation. Asbestosis is a rare but serious incurable lung condition caused by asbestos exposure, with treatment aimed only at symptoms. The NHS dates asbestos as a building material used from the 1950s to the 1990s and identifies building and construction work in that period as the main exposure route. Symptoms are shortness of breath, persistent cough, wheezing, extreme fatigue, chest or shoulder pain and, in advanced cases, clubbed fingertips, and it can take 20 to 30 years from exposure before any symptoms appear, with some people having none. Notes that compensation may be claimable.
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Shelter England
Practical route through a damp complaint in a private tenancy. The landlord must try to find the cause, and must fix the building defects behind it: a leaking roof, defective gutters and downpipes, rising damp through a failed or missing damp proof course, penetrating damp through walls, leaking pipes, and rotten or badly fitting windows. Where condensation is the cause the landlord must still fix inadequate ventilation, extractor fans, heating and insulation. Advises the landlord should re-check at least 6 weeks after the repairs, and notes a disrepair claim can usually be started up to 3 years after the harm, so it can be brought after moving out.
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Society for the Protection of Ancient Buildings
Philip Hughes on why modern impervious materials fail in old buildings. Old walls of brick or stone were bedded in lime and sand, sometimes earth or earth and lime mortars, rendered in lime and decorated almost exclusively with limewash, so the fabric absorbed and released moisture. Modern buildings instead rely on an impervious barrier. Sets the rule that pointing mortar should be a soft lime mix weaker than the surrounding brickwork, and shows the failure mode when it is not: strong cement pointing is forced off the wall, efflorescence and decay migrate into the brick faces instead of the joints, and cement render traps moisture and causes decay of earth and lime mortars behind. Cement render can sometimes be removed by working the surface over and taking it off in small pieces by forming hairline cracks, then making good with a lime mix. Paint should be replaced with limewash once existing impermeable coatings have broken down.
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UCL (Institute for Environmental Design and Engineering)
A comparison table of insulation materials by thermal conductivity (lambda, W/mK) and vapour diffusion resistance factor (mu), the two numbers that decide whether an insulation suits a breathable old wall. Bio-based: high-density wood fibre board 0.038-0.050 lambda, mu 5-10; low-density wood fibre quilt 0.035-0.040, mu 1-2; cork 0.037-0.040, mu 5-10; sheep's wool 0.035-0.040, mu 1-2; hemp 0.040-0.045, mu 1-5; straw 0.045-0.050, mu 1-2. Insulating lime plasters: hydraulic 0.800-0.900, mu 10-15; non-hydraulic 0.700-0.800, mu 5-10. Mineral board: calcium silicate 0.050-0.060, mu 5-10. Foams: open cell spray foam 0.035-0.040, mu 3-5; EPS 0.030-0.040, mu 30-70; XPS 0.025-0.035, mu 80-200; closed cell spray foam 0.023-0.026, mu 30-60; PIR 0.023-0.025, mu 50-100; phenolic foam 0.020-0.025, mu 50-100. Others: mineral wool 0.030-0.045, mu 1-5; aerogel 0.013-0.018, mu 5-10. The paper's central caution is that vapour permeability, moisture storage and liquid transport are not directly linked, so labelling a material simply 'vapour permeable' or 'breathable' is not sufficient: mineral wool is vapour permeable but is neither moisture-storing nor capillary active, and permeability is a gradual scale rather than a binary.
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UCL Discovery (Botti, University of Surrey and PRP)
Post-occupancy monitoring of a Passivhaus-certified large-scale affordable housing development, comparing measured indoor temperatures in summer 2015 against the overheating risk predicted at design stage with PHPP. The analysis found a high frequency of overheating, diverging significantly from the PHPP estimates. The causes identified were higher internal heat gains from higher occupant density and appliance use than assumed, and in some cases insufficient reliance on natural ventilation to purge excess heat. Because in-use occupancy patterns are hard to predict at design stage, the paper recommends a more robust design strategy with explicit measures to minimise summer overheating and future-proof against a changing climate. Context figure cited: fuel poverty affected 10.6 per cent of English households at the time of the study.
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University of Bath
Peer-reviewed measurement of a real hemp-lime building (Lawrence, Fodde, Paine and Walker, Key Engineering Materials 517, 2012, pages 413 to 421). Findings: the unique pore structure of the woody core of the hemp stem, the shiv, gives hemp-lime both low thermal conductivity and thermal and hygric buffering, so the wall damps swings in external temperature and passively controls internal humidity; the monolithic construction technique promotes good airtightness and minimal thermal bridging in the envelope. The paper also reports a computerised environmental model that accounts for the phase change effects seen in hemp-lime, which conventional steady-state U-value modelling misses. Material context: the hemp plant grows up to 4m in four months with low fertiliser and irrigation demand, and every part is used, the seed for food, the bast fibre for paper, clothing and resin reinforcement, and the woody core as the aggregate in hemp-lime.
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University of Bath
Laboratory testing of retrofit options on single-skin and cavity brick walls between two opposing climate chambers, with temperature, relative humidity and heat flux logged by surface sensors every 10 minutes under steady-state winter and summer scenarios (Journal of Building Engineering vol 23, pages 241-249, 2019). Findings a specifier can act on: single and cavity brick walls behaved significantly differently, and there was a high condensation risk in the non-ventilated air cavity of the double wall. A pervious lime-cement mortar render substantially improved the thermal performance of the single wall but increased the condensation risk of the cavity wall, so the same render is a good move on one construction and a bad one on the other. Adding an insulation layer reduced thermal conductance as expected, but the improvement in the summer scenario was considerably lower than in winter. The paper concludes effective retrofit depends on the material, the wall layout and the climate together, not on the material alone.
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University of Bath
Measures why hemp shiv works as an insulating aggregate, using scanning electron microscopy, CT scanning and mercury intrusion porosimetry. Findings: vessels are approximately 50 to 100 micrometres in diameter, surrounded by relatively thick fibre cells 1 to 2 micrometres in diameter, with a diffuse-porous distribution and no clear pore arrangement; pore frequency is around 20.8 vessels per square millimetre. Average accessible porosity is 76.67 plus or minus 2.03 per cent by mercury intrusion porosimetry, and between 50 and 75 per cent by CT depending on threshold and resolution. That very high porosity is the physical reason for hemp shiv's low thermal conductivity and high moisture buffer value in hemp-lime construction. Presented at the 2nd International Conference on Bio-Based Building Materials, Clermont-Ferrand, June 2017.
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University of Bath
Tests how the mix itself controls hemp-lime performance (Construction and Building Materials vol 159, pages 9-17, 2018). Both the binder to aggregate ratio and the aggregate particle size distribution were shown to affect compressive strength, flexural strength and thermal conductivity, so a hempcrete wall's numbers are a function of the recipe, not of the material category. The material is anisotropic in both behaviour and internal structure, meaning results differ by direction of loading, and the effect of binder to aggregate ratio is itself directionally dependent, indicating different failure mechanisms in opposing loading directions. A new image analysis method was used to study the internal topology. Practical consequence: hemp-lime properties must be specified and tested for the intended orientation and mix, and cannot be lifted from a generic figure.
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University of Salford
Measured results from two prototype Future Homes Standard houses built inside the Energy House 2.0 climate chamber in January 2023. The headline finding is the size of the performance gap: the two homes, built by different methods, showed a difference of only up to 8 per cent between designed and actual measured performance, against a stated typical range for new build homes of 5 per cent to 140 per cent of design specification. Airtightness on one house was measured better than design values with low heat loss. Running cost effect: the design-to-actual difference on eHome2 equated to £4.50 per month, giving a running cost of £88 per month. The chamber can reproduce conditions found across 95 per cent of the earth's inhabited land, from -20C to 40C with rain, wind, snow and solar, and holds temperature to within 0.5C. Context stated: the Future Homes Standard applies to new UK homes from 2025 and targets 80 per cent fewer carbon emissions than homes built to the 2013 regulations. The research team's conclusion is that small human errors have disproportionately large effects in a highly efficient home.
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University of Salford
Findings from the £3 million Demonstration of Energy Efficiency Potential (DEEP) project commissioned by the Department for Energy Security and Net Zero, run by Salford's Energy House Labs with the Leeds Sustainability Institute at Leeds Beckett and Loughborough University, and one of the largest UK studies of solid wall retrofit. Both a whole house approach and piecemeal retrofit cut the fabric heat loss and space heating energy bills of the Energy House by around 50 per cent, but the whole house approach carried significantly less risk of surface condensation and mould growth at junctions. Insulating solid walls could save up to 30 per cent a year on energy bills for some homes and was by far the single most effective measure for solid walled homes, with other measures unable to reach the required improvement. Modelled fuel bill savings for solid wall insulation alone were between 11 and 29 per cent depending on the condition of the wall and how much of the external wall is insulated, rising to as high as 33 per cent when combined with other measures. Measured improvements were in most cases lower than the EPC predicted. A second-order finding builders miss: after fabric retrofit the existing gas central heating system became oversized, which reduced its efficiency, though low-cost fixes were found. Energy House 1 is a full-size Victorian terraced house inside an environmental chamber that can replicate outdoor temperatures anywhere in the UK at any point in the heating season.
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University of Salford, Energy House Labs
Specification of one of the largest purpose-built building performance test laboratories in the world, opened in 2023. Two large-scale environmental chambers control temperature from -23.5C to +51C plus humidity, with weather rigs that can be placed on buildings inside. The chambers are green field sites: any type of property can be built inside, hangar doors admit construction plant, and earth pits allow real foundations to be dug so builders work as they would on site. Sensor arrays are cast into the properties as they are built. The lab's heat loss testing follows EN 17887-1:2024 (in situ testing of completed buildings, data collection for aggregate heat loss test) and EN 17887-2:2024 (steady-state data analysis for the same test).
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University of Salford, Energy House Labs
Carries several measured results from Energy House 2.0. Reversible heat pump cooling: research led by Professor Lubo Jankovic tested a heat pump with fan coils in one of the test houses, and when the temperature inside the chamber reached 32C the rooms stayed between 19C and a comfortable range, showing reversible heat pumps can address overheating in modern homes as well as heating them. Installation quality: Research Fellow Grant Henshaw's BBC Morning Live segment followed a homeowner whose air source heat pump, installed by an MCS-certified installer, was found to be undersized for the property, which is the failure mode the labs repeatedly identify. Heat3D building performance testing has been taken out of the laboratory and applied across 22 occupied homes, published in Buildings (MDPI). Other work covers monitoring to help social housing providers identify damp, mould and poor indoor environmental conditions.
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University of Salford, Energy House Labs
Cross-cutting findings from the Innovate UK funded Future Homes project, worth £3.54m in its initial phase plus a £1.4m extension, covering 52 product evaluations and business assists. Off-site timber frame systems demonstrated predictable fabric performance and reduced the performance gap. Heating system trials showed all the technologies tested can work, but stressed the critical importance of correct sizing, design, commissioning and continuous-heating regimes for low-temperature systems, which is the single most common failure mode in domestic heat pump installations. Indoor air quality studies revealed significant risks in airtight homes without active ventilation and concluded regulation needs to evolve. Smart home and customer-facing technology needs simplifying to be usable. Ongoing work covers assessing ventilation methods in homes with higher airtightness, emissions from building materials under future higher ambient temperatures, and ventilation system performance in hot outdoor conditions. Published studies from the programme include a comparison of SAP assumptions against measured U-value and airtightness in pre-1919 dwellings, and a study of the insulative effect of snow on flat roofs under extreme conditions.
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University of Strathclyde, Energy Systems Research Unit
Modelled conclusions on retrofitting the Scottish stock. Greenhouse gas reductions were achieved at every retrofit level through reduced energy demand, and at scale the cost of retrofit could be competitive with conventional responses to rising demand such as building more generation. Going deeper, the modelling showed it is possible to feed a high percentage of buildings with low carbon heat without any increase in electricity demand, a system-level benefit usually overlooked in individual retrofit decisions. Deep retrofit also raises thermal comfort and indoor air quality and can reduce fuel poverty, which affects around 30 per cent of Scottish households. The delivery model judged most promising for scale is EnergieSprong, largely because its financing offsets cost against current energy bills and recycles the saving into further retrofit, following the developed market in the Netherlands.
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A. Proctor Group
Airtight and vapour permeable wall breather membrane to BS EN 13859-2:2010. Roll 1.5 m x 50 m, thickness 0.4 mm, mass per unit area EN 1849-2 100 g/m2. Water vapour resistance EN 12572 Sd 0.02 m. Water penetration EN 1928 Class W1 before and after ageing. Tensile strength EN 12311-1 MD 240 N, CD 125 N before ageing and MD 200 N, CD 110 N after; tear resistance EN 12310-1 MD 100 N, CD 120 N; elongation MD 60%, CD 70% before ageing. Reaction to Fire EN 11925-2 Class E. BBA Certificate No. 24/7182.
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A. Proctor Group
Variable resistance vapour control layer to BS EN 13984:2013. Roll sizes 1.5 m x 50 m and 3 m x 50 m; weight 110 gsm. Vapour resistance EN 12572 Sd 0.8 m to 60 m, varying with humidity so it is more vapour resistant in winter and more permeable in summer. Air permeability BS EN 12114:2000 0.00 m3/m2.hr at 50 Pa. Nail tear resistance EN 12310-1 MD 250 N, CD 270 N; tensile strength EN 12311-1 MD 350 N/50 mm, CD 280 N/50 mm; elongation MD and CD 20%. Reaction to Fire EN 13501-1 Class E. Passivhaus certified component. Revised February 2026, version 1.005.
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A. Proctor Group
Air and vapour permeable water resistant pitched roof underlay to BS EN 13859-1:2010, with a meltblown core. Standard rolls 1 m x 50 m and 1.5 m x 50 m; mass per unit area 170 g/m2. Water vapour resistance Sd 0.015 m and vapour resistance 0.075 MNs/g to EN ISO 12572. Air permeability EN 12114 average 35 m3/m2.h at 50 Pa. Water penetration EN 1928 Class W1; hydrostatic head ISO 811 greater than 1 m, as recommended by NFRC Technical Bulletin 6. Tensile EN 12311-1 before ageing MD 330 N/50 mm, CD 270 N/50 mm; after ageing MD 280, CD 225. Elongation before ageing MD 56%, CD 68%. Reaction to Fire Class E to EN 13501-1 (EN 11925-2). Wind uplift complies with BS 5534; BBA Certificate 24/7147 for non ventilated warm and cold roofs, including roofs with solar PV, with no vapour control layer required. Can be left exposed up to three months of UV exposure.
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A. Proctor Group
Grey vapour permeable wall membrane to BS EN 13859-2:2010. Mass per unit area EN 1849-2 100 g/m2. Vapour resistance EN ISO 12572 Sd 0.08 m. Water penetration EN 1928 Class W1 before and after ageing. Tensile strength EN 12311-1 before ageing MD 240 N, CD 125 N, changing less than 30% after ageing; elongation before ageing MD 70%, CD 80%. Tear resistance EN 12310-1 MD and CD greater than or equal to 50 N. Flexibility at low temperature EN 1109, no cracking at minus 40 C or below. Reaction to Fire EN 13501-1 Class E. Revised August 2026, version 1.007.
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A. Proctor Group
Low emissivity vapour control layer to BS EN 13984:2013. Roll sizes 1.5 x 50 m, 2.7 x 100 m and 3 x 100 m; base membrane mass per unit area minimum 121 g/m2. Emissivity EN 15976 less than 0.05, giving a claimed R value of 0.72 m2K/W when used with a minimum 19 mm service cavity. Sd value EN 1931 minimum 150 m. Resistance to water penetration EN 13111:2010 W1. Tensile force EN 12311-1 (modified with EN 13859-2:2014 Annex A) minimum MD 150 N/50 mm, CD 140 N/50 mm; elongation minimum MD 50%, CD 40%; tearing resistance minimum MD and CD 180 N. Reaction to Fire EN 13501-1 Class E.
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A. Proctor Group
Self adhered vapour permeable air barrier tested to BS EN 13859-1/2:2010. Roll 1.5 m x 50 m, roll weight 24 kg; tapes 75, 100, 150 and 300 mm. Nominal thickness 0.65 mm, basis weight 292 g/m2. Water vapour permeability EN ISO 12572 (C) Sd 0.039 m; water vapour transmission BS 3177:1959 893 g/m2 per 24 hr. Resistance to penetration of air EN 12114 0.01 m3/m2.h at 50 Pa. Water penetration EN 1928:2000 Method A Class W1 before and after ageing. Peel adhesion EN 1939 5.01 N/10 mm; tensile EN 12311-1 mean MD 417 N, XD 252 N; tear EN 12310-1 mean MD 412 N, XD 286 N; flexibility no cracks at -40 C. Installation temperature -10 to +60 C, service -40 to +100 C, can be left exposed up to 120 days in the UK. Reaction to Fire Class B-s1,d0 to EN 11925-2 / BS EN 13501-1, tested over 12 mm calcium silicate or fibre cement board per BS EN 13238:2010 and free hanging. BBA Certificate No. 15/5274, Passive House Institute certified component.
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Baumit
Grey (graphite) expanded polystyrene board with square edges for external wall insulation systems. Board size 1200 x 600 mm, available in 20 to 280 mm thicknesses. Fire resistance class B1-s1-d0 approved according to ETAG 004 as stated on the page.
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Birtley Lintels (Birtley Group)
Supatherm thermally broken steel lintels. Psi values in W/mK, calculated on a 100 mm cavity with full fill insulation and a 0.45 W/mK block. ST90 by length: 750-1050 mm 0.098 to 0.057; 1200-1350 mm 0.053 to 0.048; 1500-1650 mm 0.043 to 0.039; 1800-2100 mm 0.06 to 0.052; 2250-2400 mm 0.048 to 0.043; 2550 mm 0.039; 2700-3000 mm 0.055 to 0.051; 3300-3900 mm 0.037 to 0.031. ST90HD at 1800 mm is 0.04 and ST90HDX at 1800 mm is 0.043. Birtley claim up to 80% reduction in heat loss against a standard cavity lintel, improving DFEE by up to 3% and DER by over 1%. Cavity widths 90 to 150 mm, lengths 750 to 3900 mm, hot dip galvanized to EN 1461, CE marked to BS EN 845-2.
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Catnic (Tata Steel UK)
TH90/100 heavy duty cavity lintel with a full thermal break, cavity 90-105 mm, inner leaf 100-115 mm, outer leaf 100-102 mm. The thermally broken TH and TX ranges cover cavities 90-205 mm in standard, heavy and extra heavy duty. SWL total UDL at 1:1/19:1 on 150 mm end bearings: 32 kN from 750 mm to 1800 mm, 48 kN at 1950 mm and 2100 mm, 45 kN at 2250 mm and 2400 mm. Nominal height 154 mm to 1800 mm then 229 mm. Weight 9.98 kg at 750 mm to 40.10 kg at 2400 mm.
- supplier figure RN-WVXFUS
Cordek
Cellcore HX Plus sits beneath reinforced concrete floor slabs to protect against ground heave while also insulating. Construction is a cellular expanded polystyrene core bonded to a Filcor insulation layer and protected by a thin polypropylene sheet, moulded to tolerance. BBA certified and meets NHBC Technical Standards. Specification is a two-step process Cordek set out explicitly: first fix the Cellcore HX depth and grade to suit the heave potential and the construction loading, then calculate the Filcor insulation thickness needed for the target U-value. Standard range covers common combinations of soil heave potential, concrete depth and U-value requirement.
- supplier figure RN-HP8FSO
EcoTherm Insulation (Kingspan Insulation Ltd)
Rigid PIR flat roof board to BS EN 13165: 2012 + A2: 2016 for bonded warm roof build ups. Sizes: 25 mm boards 1200 x 600 mm (0.72 m2), 50 to 160 mm boards 1200 x 1200 mm (1.44 m2); greater thicknesses achieved with two layers. Lambda by thickness: 0.027 W/mK at 25 to 79 mm, 0.025 W/mK at 80 to 119 mm, 0.024 W/mK at 120 mm and above. Average compressive stress exceeds 150 kPa at 10% compression to BS EN 826: 2013. Boards are installed over a vapour control layer or sealed metal deck, with BS 5250: 2021 and BS 6229: 2018 to be considered. Fire: under System 4 AVCP, Eco-Bond has a Euroclass rating of F; without a roof system classification from an external roof exposure test or an inorganic overlay, use must be restricted to at least 20 metres in England and 24 metres in Scotland from any point of the relevant boundary.
- supplier figure RN-8ER1JE
EcoTherm Insulation (Kingspan Insulation Ltd)
Full fill cavity board, thermal conductivity 0.022 W/mK, standard thicknesses 90, 115 and 140 mm, BBA Certificate No 24/7114. Published R-values and typical U-values (with a 10 mm clear residual cavity and skim coated plasterboard on dabs internally): 90 mm R 4.05, U 0.18 brick and light block, 0.19 brick and medium block, 0.20 brick and dense block; 115 mm R 5.20, U 0.15 to 0.16; 140 mm R 6.35, U 0.13 to 0.14 W/m2K. Calculations use lambda values brick 0.77, dense block 1.13, medium block 0.51, lightweight block 0.11 W/mK. Fire: Eco-Cavity Full Fill has a Euroclass rating of F.