Brick, Block & Mortar
323 sources in the library on brick, block & mortar. 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 9.
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Citizens Advice
Covers the national remediation programme for defective solid wall insulation fitted under ECO4 or the Great British Insulation Scheme. The affected window is work carried out between April 2022 and January 2025 where the householder got help with the cost. Ofgem or TrustMark write to affected households quoting a 'unique measure reference' number, which is also what a doorstep caller must be able to produce alongside ID. A qualified professional inspects both internal and external wall insulation, and where defects are found TrustMark arranges an installer to put them right at no cost to the householder. Contacts given are the Ofgem helpline 0808 169 4447 and TrustMark 0333 555 1234.
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HomeOwners Alliance
Identification and cost of the three damp types. Rising damp is recognised by a tide mark typically up to 1m above floor level, sometimes higher, with salt deposits in the plaster from groundwater. A damp proof course in a newer house sits about 15cm above external ground level and links to a damp proof membrane under the floor; many older houses have neither. Costs: a standalone damp survey £200 to £600 depending on property size and depth of investigation, best taken from a Property Care Association approved specialist; a good extractor fan for a condensation problem from £500; a remedial damp proof course with associated replastering to a flat 5m wall from £1,200. Advises at least 3 quotes. Condensation reduction tips include running cold water into the bath before hot, which cuts up to 90% of the steam.
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HomeOwners Alliance
Costed flood resilience measures for a house. Air brick covers £50 to £300, to be removed once flooding passes so the bricks can dry. Non return valves on drains and pipes to stop sewage backflow £50 to £500. Raising electrical sockets to about 1.5m £1,000 to £4,000. Raising door thresholds above flood level, front door and porch, £1,000 to £10,000. Sealing exterior walls around £500, with a warning it can trap damp in poor condition brickwork. Water resistant air bricks £500 to £1,000, needing careful maintenance to avoid seepage. Flood boards or flood resistant doors and windows £500 to £3,000, requiring permanently visible fixings. A pump, the most effective answer to groundwater, £50 to £2,500, with the inlet installed lower than the water being pumped. Basement tanking £10,000 to £20,000. On insurance, Flood Re is funded by a levy all UK home insurers must pay, and a home qualifies only if it was built before 2009 and is in council tax bands A to H.
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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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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
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 (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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National Grid Electricity Distribution
Contains the rules on where a meter may sit and two fully worked cost examples. Permissible meter locations: in an external meter box (recommended), inside the property on an external wall, or in a suitable weatherproof meter cubicle; the cubicle detail is 1.5m high by 0.6m wide by 0.45m deep, and the internal-wall position allows 1,250mm by 550mm. Meters must not be located inside a dustbin, coal or refuse store, above doorways, in a bathroom, toilet or shower room, in a basement or cellar, under stairs where headroom is less than 2m, on plasterboard or drywall partition walls, close to a water source that could damage the equipment or cause an electrocution risk, or anywhere in breach of BS 7671. A surface mounted meter box protrudes 230mm from the wall, so check it will not obstruct or be damaged; a flush fit box is best built into new brickwork. Once the works are complete the meter box and cable guard become the customer's property to maintain. Worked example 1, overhead supply: overhead re-connection £1,091 plus £182 plus £91, no trench, total £1,364. Worked example 2, underground supply, customer excavation: underground re-connection £980 plus 10m of cable at £26/m (£260), total £1,240; the same job with NGED excavation: underground re-connection £2,437 plus £260 of cable plus 5m grass trench at £83/m (£415) plus 5m tarmac trench at £169/m (£845), total £3,957. A joint hole is needed to expose the existing cable, with at least 200mm of excavated ground below the cable, and warning tape is laid 75mm above the cable depth. Preparatory work such as installing the meter box must be finished before the visit or the job may be cancelled and an aborted visit charged. Bespoke offers are needed to move a three phase supply, to replace an overhead cable with an underground one, for routes crossing third party land, and for routes needing traffic lights or road closures.
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Shelter England
Using the council's environmental health team to force repairs. They investigate serious repair problems that affect health or create risk, and can be approached where the landlord or letting agent ignores reports or fails to fix things in a reasonable time. Their tools include inspecting under the housing health and safety rating system, serving an improvement notice that tells the landlord how to fix the problem and sets a deadline, and taking emergency action. The council must give the tenant a copy of any notice within 7 days.
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Shelter England
Gives the fixed timescales that bind social landlords in England: investigate within 24 hours if the damp and mould is an emergency, or within 10 working days if it is very serious but not an emergency; make the home safe within 24 hours for an emergency, or within 5 working days of finishing the investigation for a very serious non emergency case. The landlord must offer alternative accommodation if it cannot fix very serious damp and mould inside those limits. Escalation is to the landlord's complaints procedure and then the Housing Ombudsman.
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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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Shelter England
Sets out when a rented home counts as unfit: conditions that seriously affect health, risk physical injury, or stop full use of the home. Lists examples including gas safety risks, unsafe electrics, fire safety failings, vermin, serious damp and mould, no hot water or heating, a leaking roof and unsafe stairs. Applies to all private, housing association and council tenancies for the whole tenancy, not just at the start. Emergency hazards must be made safe within 24 hours and the landlord must provide free rehousing if that is not possible.
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Shelter England
Splits the repairing duty. Landlord: structure and exterior, walls, windows, roof, gutters and drains, basins, sinks, baths, toilets, pipes, wiring, boilers, heaters, radiators and anything the landlord supplied. Tenant: use the home in a 'tenant like manner', report repairs and damp, and allow access. States the home must be fit to live in for the whole tenancy, that a landlord has 24 hours to fix an emergency hazard and must offer temporary housing if it cannot be made safe in that time, that all landlords must look for the cause of damp rather than blame the occupant, and that a tenant must be given at least 24 hours' written notice before an inspection.
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Society for the Protection of Ancient Buildings
Douglas Kent's technical advice note on dampness in buildings predating about 1919. Key figures: relative humidity becomes detrimental at 70% or higher; rising damp usually extends only 10 to 50mm above internal floor level, though it can reach 900mm or more depending on external ground levels, masonry type, water table and evaporation rate; timber in a normal dry living environment sits at roughly 9 to 16% moisture content and becomes susceptible to fungal decay above 21%. States that most pre 1919 buildings were built without damp proof courses or damp proof membranes by design, that rising damp is usually far less of a problem than commonly supposed, and that inserted DPMs and chemical injection are frequently unnecessary treatments applied after misdiagnosis, where maintenance and occupancy changes plus respecting the building's need to breathe are the appropriate response. Also covers rainwater penetration, condensation on porous lime surfaces and hygroscopic salts, and notes listed building consent may be required.
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Society for the Protection of Ancient Buildings
Marianne Suhr and Sally Stradling on diagnosing and repairing fireplaces, flues and chimneys in old domestic buildings, including fire risk, alterations and energy efficiency. Dimensional guidance includes a 300mm (12 inch) diameter flue 3m (10 ft) high, an iron or copper canopy finishing about 750mm above the fire bed and measuring roughly 900mm wide by 600mm deep, reducing a fireplace opening height to 600mm, a restricted throat 100mm (4 inches) from the back of the grate, and traditional grouped flues of about 225 by 225mm (9 by 9 inches) with slender withes between them. Historic parging used lime or earth with fresh cow dung, mixes cited as 1 part lime putty to 3 parts cow dung, sometimes 1:1, and 1 part cow dung to 4 parts haired lime mortar made from 1 part lime to 3 parts sand. Also covers downdraught from a nearby tall building, tree or hill, spalling, and combustion air inlet sizing.
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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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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
Tests the widespread belief that laying an impermeable ground bearing slab in a building with no damp-proof course drives ground moisture up the adjacent walls by capillary action. Wall, soil and atmospheric moisture content were measured over a three-year period in a historic building before and after a vapour-sealed ground floor was installed. Using timber dowel measurements, the moisture content within the adjacent rubble-fill wall did not vary in response to wall evaporation rates and did not increase after the vapour-proof barrier was installed above the floor, indicating the moisture levels in that wall were not driven by capillary rise. The finding matters because the opposite assumption is routinely used to argue against sealing a solid floor in an old house.
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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 Portsmouth
A year-long practical test of rising damp on walls built from different mortars, compared against theoretical models. Findings: mortar characteristics significantly affect the height to which damp rises, and the rate of water absorption into the mortar is the key factor determining the height of the rising damp front, with a strong correlation to the Sharp Front Model. A second measured result is useful for diagnosis: walls that had received rising damp treatment were warmer than the untreated control walls, because reducing surface moisture removes the evaporative cooling effect, which is why a damp wall reads cold to the touch and on a thermal camera. The paper reviews the controlling mechanisms of capillary effect, water absorption, evaporation and salt formation.
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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 Strathclyde, Energy Systems Research Unit
A breakdown of the Scottish housing stock drawn from the 2015 Scottish House Condition Survey, covering dwelling types, ages, heating systems, sizes and U-values. Headline fuel split: 79 per cent of the Scottish housing stock runs on gas, 12 per cent on electricity, and oil and other fuels together account for around 10 per cent. Flats, a category that includes maisonettes, two-storey flats and tenements, make up the highest proportion of buildings in Scotland, which is why communal ownership and shared stairwells shape what retrofit is possible there. Semi-detached houses are described as paired by a common wall and designed to use less space than detached; terraces, common in old industrial towns and popular through the 20th century for high density working class housing, share walls on both sides.
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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
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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Ancon (Leviat)
Ancon ST1, a Type 1 heavy duty tie to PD 6697, suits cavities 50 mm to 225 mm and any building height anywhere in the British Isles, with drip holes in the cavity span so one tie works in insulated and open cavities. ST1 lengths: 200 mm for 50-75 mm, 225 for 76-100, 250 for 101-125, 275 for 126-150, 300 for 150-175, 325 for 176-200, 350 for 201-225. Type 1 performance is declared in M2 mortar. Staifix RT2, Type 2 general purpose, covers 50-150 mm cavities in domestic and small commercial buildings up to 15 m, lengths 200/225/250/275 mm across the same cavity bands, UKCA and CE marked and usable to NHBC standards. HRT4 is the Type 4 light duty tie. The Teplo BF1 to BF4, Teplo-BFR and Teplo-R basalt fibre ties are the low thermal conductivity option.
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Ancon (Leviat)
Ancon recommend a tie length that gives between 62.5 mm and 75 mm of embedment in each leaf. Full masonry-to-masonry table of cavity width against tie length in mm: 50-75 needs 200; 76-100 needs 225; 101-125 needs 250; 126-150 needs 275; 151-175 needs 300; 176-200 needs 325; 201-225 needs 350; 226-250 needs 375; 251-275 needs 400; 276-300 needs 425; 301-325 needs 450; 326-350 needs 475; 351-375 needs 500; 376-400 needs 525; 401-425 needs 550; 426-450 needs 575. Spacing is referred to PD 6697:2019.
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Ancon (Leviat)
Background figure: ties before 1978 were usually galvanised mild steel and some corroded within 15 to 20 years, expanding to seven times their original thickness and cracking brickwork at the bed joints. Product lengths by cavity. Ancon 63 Mechanical/Mechanical MM63, 12 mm diameter holes: 200 mm for 45-70 mm cavity, 225 for 71-95, 250 for 96-120, 300 for 145-170. Ancon 63 Resin/Mechanical RM63 for perforated, low density or friable inner leaves, 11 mm holes: 200 mm for 35-60, 225 for 61-85, 250 for 86-110, 300 for 135-160. Staifix Resin/Resin: 10 mm hole normally, 12 mm where a sieve or test facility is needed; 180 mm for 40-60, 200 for 61-80, 220 for 81-100, 240 for 101-120, 260 for 121-140, 280 for 141-160. Stairib ribbed bar in 6 mm (10 mm hole) or 8 mm diameter (12 mm hole). AC 31 for replaced outer-leaf bricks: 175, 200, 225, 250, 275, 300 mm; AC 31C cranked 25 mm in 175, 200, 225 mm. Teplo-BFR basalt fibre remedial tie has a thermal conductivity of only 0.7 W/mK, 7 mm bar in a 10 mm hole.
- supplier figure RN-6KX51G
Ancon (Leviat)
Three ways of joining new masonry to an existing wall. The Universal Wall Starter kit contains two channel sections plus all ties, plugs and screws to join a single skin of masonry 2.4 metres high to an existing wall. The Staifix Starter Tie is a screw-in tie supplied with an 8 mm nylon plug, used without cutting joints, aimed at conservatories, extensions and garden walls. The Staifix Cavity Starter Tie is a screw-in tie with an 8 mm nylon plug and a neoprene o-ring for building an inner leaf of blockwork inside an existing structure.
- supplier figure RN-7JIF4X
Ancon (Leviat)
Staifix tie lengths by cavity width. HRT4 (Type 4 / Type A, replaces the butterfly tie): 200 mm for 50-75 mm cavity, 225 mm for 76-100, 250 mm for 101-125, 275 mm for 126-150. RT2 general purpose (Type 2, replaces the double triangle tie): same four lengths for the same four cavity bands. Staifix-Thor Helical TJ2 hammer-driven tie for thin joint blockwork: 205 mm at 50 mm cavity, 230 at 75, 255 at 100, 280 at 125, 305 at 150. STF6 timber frame tie (Type 6) suits 50, 75 and 100 mm cavities and comes with an annular ring shank nail. HRT4 is limited to external walls of houses not over 10 m high, and is a Type A tie for internal separating walls of any height. RT2 covers houses and small commercial up to 15 m but is unsuitable for internal separating walls of new attached dwellings. All austenitic stainless steel with safety ends and multiple drips. Field of use is set by PD 6697 table 12, BS 5268-6.1 and Approved Document E.
- supplier figure RN-QSBDQN
BAL (Building Adhesives Ltd)
Manufacturer coverage table for an SBR primer and admixture, the numbers behind a preparation estimate. As a primer, coverage is 12 m2 per litre undiluted (60 m2 from a 5 litre tub), 36 m2 per litre diluted 1:2 with water (180 m2 per 5 litres) and 40 m2 per litre diluted 1:4 (300 m2 per 5 litres). As a bonding and gauging additive, coverage is 5 m2 per litre for 12mm plastering, 1.5 m2 per litre for 12mm rendering and 0.25 m2 per litre for 50mm screeding, the latter two quoted at 10 litres per 50 kg of OPC. As a slurry coat with Portland cement it covers 3 m2 per litre, mixed 1 part sand to 1 part cement by weight. Drying time is 15 to 30 minutes at 20C. Pack sizes are 1 litre and 5 litres. Approved backgrounds include plasterboard, rendering and shower areas. For an integral plaster mix the dose is 2 to 4 litres of SBR.
- supplier figure RN-JNOVCS
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.