References

Foundations & Groundworks

134 sources in the library on foundations & groundworks. 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 3 of 4.

1. fair RN-700UXJ

   Scottish Water

   Two separate distances that both bind a build near a water main, with published tables. Access Distance, the legally supported clearance kept in every direction so the main can be repaired, maintained or renewed, measured from the outside of the pipe, with no buildings, structures or development permitted inside it: up to 180mm internal diameter, 3m; over 180mm up to 14 inch/350mm, 4.5m; over 350mm up to 18 inch/450mm, 6m; over 450mm up to 24 inch/600mm, 8m; over 600mm, minimum 10m depending on site conditions. Those minima assume a pipe invert up to 2 metres deep and may increase with depth, difficult topography or a main deeper than 2m; in constrained urban situations NJUG guidelines apply in pavements for small diameter distribution mains, larger mains in constrained urban roads need a risk assessment and method statement, and strategic mains over 600mm need detailed design referencing the Washington Suburban Sanitary Commission Pipeline Design Manual. Stand-off Distance is separate: the minimum distance habited property should sit from the main so a burst does not damage it, based on the crater size at the main's operating pressure: 2 bar 2.5m, 4 bar 5.0m, 6 bar 7.5m, 8 bar 10m, 10 bar 12m, 12 bar 14.5m, 14 bar 17m, 16 bar 19.5m, 18 bar 22m. Stand-off distances may be increased where the main is high pressure or deeper than 2m to invert, or where the property is at increased flood or damage risk if the main fails.

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2. fair RN-5CD2AJ

   Severn Trent Water

   Severn Trent's homeowner route. A Formal Build Over Application is required where the sewer is larger than 150mm, where a manhole must be moved, altered or built over, or where the project fails the self-certification criteria; smaller works can use the self-certification form. The company states it cannot grant approval retrospectively. Review of a formal application takes up to 10 working days, then provisional approval with conditions, then building, then a post-construction CCTV survey report before final approval; any remedial cost falls on the applicant. Permitted development rights and planning permission do not remove the need for the sewer approval, because utility locations are not considered in the planning process. Since the October 2011 private sewer transfer Severn Trent maintains most shared drains and sewers in its region, and most of those transferred pipes do not appear on maps. Advises early contact where the sewer is 300mm diameter or over, as permission may not be granted. A protective strip, measured from the centre of the pipe, must be kept clear for maintenance, sized by pipe diameter.

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3. fair RN-KW1EOK

   Severn Trent Water

   The technical rules a builder actually needs. Fees: Class 1 up to and including 150mm sewers £169.50, Class 2 225mm sewers £194.70, Class 3 complex applications at cost. A complete application normally gets a decision within 10 working days. Applies to existing homes extending over small diameter sewers of 100mm to 225mm; not for new-build. Construction rule for both building close to and building over: where foundations come within 1.0m of the sewer at any point they must be taken down below the invert level of the sewer; beyond 1.0m a 45 degree line may be taken from a point one metre clear of the sewer up to the required footing level. The 3.0m proximity is measured from the nearest point of the building including foundations to the centreline of the sewer, and depth is measured to the pipe invert. No pre-works CCTV and electro-location survey is needed for 100mm or 150mm sewers if the position is demonstrated and the foundation shown to be harmless, or for 225mm sewers if the building is no closer than 1 metre; otherwise a survey is required, and a post-works CCTV survey is always required. Any access chamber or rodding eye falling inside the new building must be replaced by a new manhole on the sewer line outside the building, with connections re-laid. Complex cases include a formal easement in the deeds, sewer depth over 3 metres, pressurised rising mains (never permitted to be built over), strategic sewers, and piling or ground stabilisation. All work must comply with Building Regulations 2010 Part H4 and be approved by building control before backfilling. CCTV surveys must follow the WRc Model Contract Document for non-man-entry sewer inspection and the UK Water Industry Manual of Sewer Condition Classification.

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4. fair RN-S4699J

   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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5. fair RN-0F64CJ

   Southern Water

   Two routes are offered, a self-declaration and a formal approval, with published criteria and fees. Self-declaration criteria include: pipe diameter 225mm or less and less than 3m deep; trench fill foundations designed to be at least 150mm below the pipe invert where within 3m horizontally of the public sewer; a minimum 300mm headroom between the underside of the new floor slab and the crown of the pipe; total coverage of the sewer less than 6 metres including pipework already built over; a minimum 1m width left between the boundary and the proposed extension so the garden is not built across its full width; and, where the sewer passes through a load-bearing wall, a foundation design complying with Part H4 and Southern Water's design criteria. The self-declaration is reviewed within 5 days for completeness and a conditional approval letter follows within the next 2 weeks; relocating a manhole chamber or doing minor pipe repairs adds an £84 inspection fee. Formal applications include a CCTV survey in the fee, and £200 is refunded if the applicant supplies their own compliant CCTV survey or if no survey turns out to be needed. A Sewer Protection Agreement carries a separate legal fee of approximately £250 for domestic or residential property and £400 for commercial. Required drawings: existing and proposed site plan at 1:100 or larger showing sewers and manholes, a site location plan at 1:1250 or larger, and a cross-section foundation design at 1:100 or larger. Practical location tips for homeowners: check the deeds, look for manholes and ask neighbours, trace the line and cautiously dig a trial hole, and run a tap or flush drain tracing dye and watch a manhole with a torch to establish direction of flow.

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6. fair RN-9A6DJF

   UK Power Networks

   Separates the four things homeowners confuse. The electricity supply (the incoming service cable and cut-out) is moved by the DNO, and the stated common triggers are extending or renovating, building a conservatory, or moving it somewhere more accessible. An overhead power line into the property is moved by the DNO, typically because the cable is in the way of an extension, because fascia, cladding or windows are being replaced, because the pole is in the way and the customer wants the run put underground, or purely for appearance. The electricity meter is legally owned by the electricity supplier and only the supplier can move it; UK Power Networks can move the electricity board, but the supplier must still return to reconnect the meter. The consumer unit or fuse box is neither the DNO's nor the supplier's work: only a qualified electrician can advise and carry it out, although the supplier may need to attend to turn the electricity off.

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7. fair RN-1BHZYL

   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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8. fair RN-32UXA9

   Wessex Water

   A set charge of £325 (non-refundable) applies to applications to build over or near a public sewer. The submission needs a plan and a sectional drawing showing the type and depth of the proposed foundations, with structural calculations where the chosen foundation type requires them. Wessex Water normally expects strip or trench fill foundations wherever possible, and treats raft, piling and cantilever footings as designs needing extra justification. Work must not start on site until formal approval is granted. Where piling foundations are used, Wessex Water carries out a post-works CCTV survey; other further inspections are undertaken by the council's building control. The company recommends locating the sewers well in advance of starting any building work.

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9. fair RN-04F7JS

   Wessex Water

   Six criteria which, if all met, let a homeowner build near (not over) a public sewer without notifying Wessex Water at all. Development type must be a single new dwelling, a domestic extension, a domestic garage or minor outbuilding, or a single block of flats; multiple dwelling developments and multiple unit industrial or retail schemes are excluded. Foundation type must be strip, trench or pad footing; raft, piling and cantilever footings are not eligible. Foundations must be a minimum of 500mm (0.5m) clear from the edge of the closest public sewer including the outer wall of any chambers. Foundations installed between 500mm and 2000mm clear of the sewer must be taken to a depth below the bottom of the sewer pipe. The sewer must be gravity-based (foul, rainwater or combined), meaning an open pipe visible in the manhole rather than the fully enclosed pipe of a pumped system. The sewer must not be strategic; strategic sewers typically run 12 inches (300mm) diameter or greater but can be smaller, and Wessex Water will check its records on 01225 526333. If all six are met, save the printable PDF of the conditions for the record and give a copy to building control, and keep photos and drawings as evidence.

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10. fair RN-3JPZPI

    Yorkshire Water

    Consent is needed before starting building work over or within 3 metres of a public sewer. If a Building Regulations application has been made, the local authority building control consults Yorkshire Water on the applicant's behalf and the applicant should ask for a copy of the response; without a Building Regulations application, a direct build-over enquiry can be submitted for an upfront fee. Fees: £144 for a desktop study only, £449 for a desktop study plus site inspection. Acknowledgement within 5 working days of application and payment; the technical assessment takes about 14 days and checks the location and condition of nearby assets, past blockages, and land rights such as easements and protected strips. Hard limits: no building over any access point (manhole, gully or inspection chamber), and nothing near pipes larger than 225mm diameter or deeper than 3m. Minor alterations, meaning removing or relocating a manhole, gully or inspection chamber, altering chamber levels, or replacing pipework, are only permitted on pipes inside the property boundary up to 225mm diameter, less than 3m deep and no more than 20m long; anything bigger, deeper or a rising main needs a sewer diversion instead. A property built after 2011 may have unadopted pipework, and a NAV rather than Yorkshire Water may be the sewerage provider. Contact technical.sewerage@yorkshirewater.co.uk. The acceptance letter should be kept for building regulations and for sale of the property.

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11. supplier figure RN-CGA7RH

    ACO Technologies

    HexDrain B 125 is a polypropylene channel to BS EN 1433 Load Class B 125, for domestic drives and small private car parks. Overall channel depth 100 mm. Supplied with a corrosion resistant black composite HeelGuard grating using 8 mm slots, held by the Drainlock bar-less locking device with an anti-shunt feature. Accessories: 110 mm diameter vertical outlet connector part 11285, roddable foul air trap 110 mm part 11191, closing endcap part 11085 and sump part 11385 with silt bucket.

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12. supplier figure RN-K53NA0

    ACO Technologies

    HexDrain is a recycled polypropylene channel drain rated Load Class A 15 to BS EN 1433, suitable for pedestrian domestic use on paths, patios and cycleways. Overall channel depth 80 mm, which makes it the shallow option where dig depth is limited. Channels clip together and the range includes corner units, outlets, an accessory bag (part 19287) and a sump unit (part 19558). ACO state that fitting a B 125 grating to a HexDrain channel does not raise the system rating, which stays at A 15 because it is set by the channel body; HexDrain B 125 is the product for light vehicles.

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13. supplier figure RN-O8RP5Z

    ACO Technologies

    RainDrain is made from ACO high strength polymer concrete rather than plastic, and is rated up to Load Class A 15 for domestic use; RainDrain B 125 is the version for cars or frequent loading. Channels interlock. A Brickslot grating variant is available in B 125 for driveways where a slot rather than a visible grating is wanted. ACO note two-person handling for the polymer concrete bodies.

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14. supplier figure RN-OMFONB

    Brett Martin

    PVC-U underground drainage from 110 mm to 400 mm diameter, made to BS EN 1401-1 with BBA certificate 87/1898 for the 110 mm PVC-U pipe. Plain ended pipe wall thicknesses: B4001 110 mm x 3 m and B4011 110 mm x 6 m are 3.2 mm; B6001 160 mm x 3 m and B6011 160 mm x 6 m are 4.1 mm; the SN8 160 mm versions B6001 SN8 and B6011 SN8 are 4.7 mm. Socketed pipe socket depths: 70 mm at 110 mm, 95 mm at 160 mm, 110 mm at 200 mm. Both 110 mm and 160 mm ranges come in SN4 and SN8 stiffness. Gradient guidance: for flows under 1 l/s, pipes not exceeding 100 mm nominal bore at gradients not flatter than 1:40 have proved satisfactory; where peak flow exceeds 1 l/s a 100 mm bore may be laid at not flatter than 1:80 provided at least one WC is connected; a 150 mm bore may be laid at not flatter than 1:150 provided at least five WCs are connected. With a high standard of design and workmanship, 1:130 at 100 mm and 1:200 at 150 mm have been used successfully. The guide states that increasing pipe diameter to compensate for insufficient fall is not a satisfactory solution because it reduces velocity and depth of flow and encourages deposits. Also covers bedding materials, trench preparation, ground load protection and inspection chamber assemblies.

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15. 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.

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16. supplier figure RN-JEZX39

    Cordek

    Filcor expanded polystyrene lightweight structural fill, offered in a range of compressive strength grades to match the loading, from pedestrian to vehicular. Standard sheet or block size 2400 mm long x 1200 mm wide with the depth made to order, minimum depth 25 mm and maximum depth 1200 mm; any shape or profile can be cut, and Cordek hire out a hot wire cutter. Flame retardant grades available. Where Filcor may contact petroleum, hydrocarbons or solvents it must be encapsulated in Puraflex VOC membrane, either on site or supplied pre-wrapped. Water resistant with a long design life, and provides insulation as well as fill.

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17. supplier figure RN-2A8CZS

    Cordek

    Compressible low density expanded polystyrene, coloured green, used against lateral heave on the inside face of piled ground beams or deep trench fill foundations. Thickness selection table against soil analysis: modified plasticity index 10-20, low shrinkage potential, NHBC recommended void zero, Heaveguard thickness zero; 20-40, medium, 25 mm void, 50 mm Heaveguard; 40-60, high, 35 mm void, 75 mm Heaveguard. Above 60 or higher than high, Cordek must be consulted. Critical limitation stated on the page: Heaveguard and all other compressible polystyrenes do not compress significantly until loads exceed 20 kN/m2, and 40 kN/m2 is needed to produce 50% compression, so Heaveguard is not recommended under ground floor slabs, piled beams or pile caps. Meets NHBC Technical Standards. Also available as a pile collar.

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18. supplier figure RN-M382W2

    Delta Membrane Systems

    HDPE cavity drain membrane. Stud height 20 mm, sheet thickness 1 mm, roll size 2.0 m x 20 m. Compressive strength 150 kN/m2. Drainage capacity 10 litres per second per metre, equal to 600 litres/min/m or 36,100 litres/hour/m, and 1.25 litres/second/m2. Air volume between studs 14 litres/m2. R value 0.18 m2K/W. Temperature resistance -30 C to +80 C. Reaction to fire Class E to EN 13501-1. The 20 mm stud gives roughly four times the drainage rate of the 8 mm product at the cost of depth taken off the room.

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19. supplier figure RN-982ZU5

    Delta Membrane Systems

    HDPE cavity drain membrane with DELTASAFE additive. Stud height 8 mm, sheet thickness 0.5 mm, roll size 2.4 m x 20 m. Compressive strength greater than 250 kN/m2. Drainage capacity 2.25 litres per second per metre, equal to 135 litres/min/m or 8,100 litres/hour/m. Air volume between studs 5.3 litres/m2. R value 0.12 m2K/W. Temperature resistance -30 C to +80 C. Reaction to fire EN 13501-1:2018 Class B-s2,d0, which is a higher fire classification than the Class E typical of plain HDPE cavity drain membranes.

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20. supplier figure RN-W9PHY4

    Forterra

    Thermalite Floor Block 4 for beam and block floors. Compressive strength 4 N/mm2, design lambda 0.16 W/mK, dry density 660 kg/m3. Single size: height 215 mm, length 440 mm, width 100 mm, weight 7.7 kg, face dimensions 440 x 215 mm.

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21. supplier figure RN-MHQJAX

    Forterra

    Thermalite Hi-Strength 7 Trenchblock, tongue and groove with integrated hand holds. Compressive strength 7.3 N/mm2, lambda below ground 0.29 W/mK, dry density 730 kg/m3, face dimensions 440 x 215 mm and 440 x 140 mm. Classified DS1-4 for resistance to ground contamination, so usable across a wide range of ground conditions. All 140 mm high trenchblocks are supplied flat-ended, without hand holds or tongue and groove. Manufactured to BS EN 771-4.

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22. supplier figure RN-J40OKU

    Forterra

    Thermalite Trenchblock 3.6 tongue and groove for below-ground construction. Compressive strength 3.6 N/mm2, lambda below ground 0.24 W/mK, dry density 600 kg/m3, height 215 mm, length 440 mm, widths 255 mm and 300 mm. Note the below-ground lambda is quoted separately from the 0.15 W/mK design value used above DPC for the equivalent 3.6 N/mm2 block.

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23. supplier figure RN-R8XVFA

    GRAF UK

    EcoBloc Inspect Flex crate, 800 x 800 x 320 mm, void ratio 96%, stackable and inspectable. GRAF's distinguishing claim is that the module accepts inspection cameras and maintenance jetting equipment through the crate, so the system can be checked and cleared rather than sealed and forgotten. Published capacities for the same unit: gross volume 0.205 m3 and net volume 0.199 m3, polypropylene, 8 kg, vertical ultimate compressive strength 340 kN/m2 and lateral 82 kN/m2, and installable to 5 metres depth under heavy loads.

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24. supplier figure RN-ABFSB5

    H+H UK

    Celcon Foundation Blocks for below ground work. Two strengths, 3.6 N/mm2 and 7.3 N/mm2, at densities 600 kg/m3 and 730 kg/m3. Thermal conductivity below ground is quoted separately as 0.24 W/mK and 0.29 W/mK, and H+H note explicitly that these figures differ from the above-DPC values because moisture content below ground is higher. A single foundation block replaces two skins of blockwork below DPC.

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25. supplier figure RN-A9044P

    IKO PLC

    IKO Hyload Original damp proof course: 1.25mm thick, supplied in 20m (20,000mm) rolls in widths of 100, 112.5, 150, 175, 225, 275, 300, 337.5, 350, 360, 375, 400, 450, 500, 525, 600, 650, 700, 750, 800, 900 and 1000mm. BBA certified since 1967 and CE marked.

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26. supplier figure RN-9LL9I8

    IKO PLC

    IKO Hyload Universal damp proof membrane, available as 1200 gauge (300 micron, 0.3mm) or 2000 gauge (500 micron, 0.5mm). Roll lengths 12,500mm and 25,000mm. CE marked. IKO notes this membrane type has been specified as a damp proofing material since 1973. The gauge-to-micron conversion is useful because merchants quote gauge and specifications quote microns.

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27. supplier figure RN-Q3AE0Z

    Kingspan Insulation

    Extruded polystyrene (XPS) boards, 1250 x 600 mm. Declared compressive strength: GG300 is 300 kPa and GG500 is 500 kPa when tested to BS EN 826. Declared thermal conductivity: GG300 0.033 W/mK across 30 to 180 mm; GG500 0.034 W/mK at 50 mm and 0.036 W/mK at 80 and 100 mm. Fire: under System 4 AVCP, Kingspan GreenGuard has a Euroclass rating of F.

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28. supplier figure RN-KFPK7L

    Kingspan Insulation

    Fibre-free rigid thermoset polyisocyanurate (PIR) floor board to BS EN 13165: 2012 + A2: 2016, foil faced both sides, for solid concrete and suspended ground floors. Declared thermal conductivity 0.022 W/mK. Declared compressive stress 120 kPa at 10% compression to BS EN 826. Water vapour resistance to BS EN 12086 greater than 50 MNs/g for the insulation core and greater than 100 MNs/g for the composite foil facing. R-values are thickness divided by 0.022 rounded down to the nearest 0.05 m2K/W. Fire: under System 4 AVCP, TF70 has a Euroclass rating of F.

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29. supplier figure RN-7RJFBX

    Lignacite

    Product data updated 22 December 2025. Face size 440 x 215 mm, thickness 100 mm and 140 mm. Mean unit strength 3.6, 7.3 and 10.4 N/mm2. Group 1 solid blocks, dimensional tolerance Category D1, net dry density 1450 kg/m3. Thermal conductivity 0.47 W/mK at 3% moisture (internal use) and 0.51 W/mK at 5% moisture (external use). Reaction to fire Class A1, moisture movement less than 0.5 mm/m, frost resistance to PD 6697 Table 15. BSI Kitemarked and certified to BS EN 771-3, Category 1 masonry units. Lignacite recommend 215 mm walls be built from 100 mm blocks laid flat, and that 7.3 N/mm2 blocks be used below ground where exposed to external soil. 3.6 or 7.3 N/mm2 blocks are used as beam and block infill, with the 3.6 N transverse tested.

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30. supplier figure RN-C8IADH

    Lignacite

    Product data updated 8 January 2026. Dense concrete block, generally 440 x 215 mm face size, with the 140 mm Midi at 290 x 215 mm. Mean unit strengths 7.3, 10.4, 17.5, 22.5 and 30 N/mm2, the widest strength range of the Lignacite ranges. Group 1 solid, tolerance Category D1. Net dry density 2000 kg/m3 for the 7.3 and 10.4 N blocks and 2100 kg/m3 for the 22.5 N and above. Thermal conductivity 1.33 W/mK at 3% moisture and 1.43 W/mK at 5%. Reaction to fire Class A1, moisture movement less than 0.6 mm/m. BS EN 771-3, BSI Kitemarked, Category 1. Used for internal and fire break walls and as beam and block floor infill.

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31. supplier figure RN-3MYOR4

    Mannok (formerly Quinn Building Products)

    Expanded polystyrene board, lengths 1200, 1800 and 2400 mm, widths 600 and 1200 mm, thicknesses 25 mm to 100 mm as standard. Thermal conductivity 0.036 W/mK. Compressive strength at 10% deformation 100 kPa; bending strength 150 kPa. Water vapour diffusion factor 30 to 70; water vapour permeability 0.010 to 0.024 mg/PaNM. Long term water absorption WL(T)05 by total immersion, less than 1% by partial immersion. Approximate density 20 kg/m3. Fire Classification E.

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32. supplier figure RN-GJPO5X

    Mannok (formerly Quinn Building Products)

    Expanded polystyrene board, lengths 1200, 1800 and 2400 mm, widths 600 and 1200 mm, thicknesses 25 mm to 100 mm as standard. Thermal conductivity 0.035 W/mK. Compressive strength at 10% deformation 150 kPa; bending strength 200 kPa. Water vapour diffusion factor 40 to 100; permeability 0.007 to 0.018 mg/PaNM. Long term water absorption WL(T)05 total immersion, less than 1% partial immersion. Approximate density 25 kg/m3. Fire Classification E. Certified by IAB and BBA for use in underfloor heating systems.

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33. supplier figure RN-0GFGNQ

    Mannok (formerly Quinn Building Products)

    Expanded polystyrene board, lengths 1200, 1800 and 2400 mm, widths 600 and 1200 mm, thicknesses 25 mm to 100 mm as standard. Thermal conductivity 0.034 W/mK. Compressive strength at 10% deformation 200 kPa; bending strength 250 kPa. Water vapour diffusion factor 40 to 100; permeability 0.007 to 0.018 mg/PaNM. Approximate density 30 kg/m3. Fire Classification E.

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34. supplier figure RN-UTVV6P

    Mannok (formerly Quinn Building Products)

    Expanded polystyrene board, lengths 1200, 1800 and 2400 mm, widths 600 and 1200 mm, thicknesses 25 mm to 100 mm as standard. Thermal conductivity 0.038 W/mK. Compressive strength at 10% deformation 70 kPa; bending strength 115 kPa. Dimensional stability DS(N)5 length, DS(N)2 width. Water vapour diffusion factor 20 to 40; water vapour permeability 0.018 to 0.036 mg/PaNM. Long term water absorption WL(T)05 by total immersion (less than 5%), less than 1% by partial immersion. Approximate density 15 kg/m3. Fire Classification E.

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35. supplier figure RN-4FQVCR

    Marshalls

    Modal X Priora permeable concrete paving. Available in a textured finish, eight colours, seven plan sizes, in 60 mm or 80 mm depth, plus three complementary sett sizes in a riven texture. Nibs on the edges of each unit let water drain into the joints and into a prepared sub-base, then to ground or a controlled release to drain, removing the need for point drainage. Marshalls state the edge detail lets units be laid in any direction while still achieving 40% more interlock than standard paving. Example unit: Modal X Pro Priora Textured Riven 240 x 160 x 80 mm, approximate unit weight 8 kg, pack weight 1516 kg, made to order. Marshalls flag that maximum loading suitability does not apply to every size and depends on the install method, bond pattern and sub-base design. A non-permeable version of the same range is available.

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36. supplier figure RN-M21MDR

    Newton Waterproofing Systems

    CDM 503 HDPE cavity drain membrane, white. Unit weight 0.5 kg/m2, sheet thickness 0.6 mm, stud height 3 mm. Water tightness at 60 kPa for 24 hours, pass. Used on walls, floors, vaults and tunnels as part of the Newton CDM System for below ground waterproofing under BS 8102:2022, which Newton note requires a maintainable system and a waterproofing specialist in the design team.

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37. supplier figure RN-ABMIDM

    Newton Waterproofing Systems

    CDM 508 HDPE cavity drain membrane, white. Overall height 8.0 mm, membrane thickness 0.45 mm, stud height 7.0 mm. Two densities, 500 g/m2 and 700 g/m2, in 2.0 m x 20 m (40 m2) and 2.4 m x 20 m (48 m2) rolls, codes M1-5-40, M1-5-48, M1-7-40, M1-7-48; only the 700 g/m2 variants are used on floors. Packaged weight 20, 24, 28 or 33.6 kg. Working temperature -50 to +80 C, service temperature -40 to +80 C, softening temperature 126 C. Installed performance: water tightness at 60 kPa for 24 h pass, tensile strength MD 416 N and CD 488 N, resistance to static loading over 20 kg, compressive strength 180 kN, fire resistance E, application Type V. Guaranteed against deterioration for 30 years, BBA Agrement Certificate 22/6357. Capable of delivering a Grade 3 internal environment under BS 8102:2022 where ventilation is also provided. Substrates: concrete, brick, concrete block, ICF with longer fixing plugs; floors over a concrete raft or slab or Fibran XPS 500-C.

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38. supplier figure RN-GUT8FF

    Plasmor

    Stranlite Foundation block. Dry density 1400 kg/m3, strengths 7.3 N/mm2 and 10.4 N/mm2. Sizes 300 x 275 x 140 mm, 300 x 250 x 140 mm and 350 x 250 x 140 mm. Pack quantities 72 blocks for the 300 mm sizes and 48 for the 350 x 250. Blocks per square metre: 300 x 250 x 140 gives 25.6 laid 300 mm wide and 21.5 laid 250 mm wide; 300 x 275 x 140 gives 23.4 laid 300 wide and 21.5 laid 275 wide; 350 x 250 x 140 gives 25.6 laid 350 wide and 21.5 laid 250 wide.

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39. supplier figure RN-ZKZNEQ

    Polypipe

    Cell data. Polystorm Lite, product code PSM2, 1 m x 0.5 m x 0.4 m high, unit weight 7 kg, cube storage volume 0.19 m3 or 190 litres, surface area 55% perforated, maximum compressive strength 20 tonnes per square metre, 15 cells per pallet. Polystorm, product code PSM1, same 1 m x 0.5 m x 0.4 m size, unit weight 9 kg, storage volume 0.19 m3 or 190 litres, maximum compressive strength 40 tonnes per square metre, 15 per pallet. The range is designed to a 95% void ratio and spans 20 to 80 tonnes per square metre load bearing capacity. Ancillaries include a basic silt trap PSMST160, an advanced 15 litres/sec silt trap PSMSTA160/15, round cover and frame UG501, square UG502, 450 mm silt trap lid and frame UG512 and a 460 mm lockable plastic cover and frame UG511.

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40. supplier figure RN-S5DFMS

    Polypipe Civils and Green Urbanisation

    Polystorm geocellular range for retention, attenuation and infiltration. Headline figures: 95% void ratio compared with traditional aggregate, load bearing strength from 20 to 83 tonnes/m2 across the range, 60 plus years design life, 100% recyclable. Variants listed are Polystorm R, Access, Inspect, Deep, Xtra, Biomat, Catchpit, Silt Trap, Low-Flow Control Unit and accessories, with the deeper units aimed at greater burial depths.

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