IWI to suspended floor, perpendicular joists (access below) [Version ID #235]

Detail summary

IWI system detail for insulating a suspended internal floor accessible from underneath in order to retain an existing floor finish. Design for an Internal wall insulation system with intelligent membrane. Drawn is a junction detail for the IWI to the edge of the floor and insulation around the joists.

VALUES: Target wall U-Value: 0.3 W/m²K \ Target floor U-Value: 0.2 W/m²K

Technical description

Section detail. IWI to internal floor Perimeter to insulated suspended timber floor in perpendicular joists.

SUGGESTED INSTALLATION SEQUENCE:

Before installation: Remove all timber fixtures: Skirting, Picture Rails, Dado Rails etc. Remove curtain rails. Remove electrical socket/ telephone/cable socket outlets. Re-fix/renew all removed once insulation complete.

1.) Remove wallpaper and plaster if necessary, any fixings and skirting board. 2.) Lift floorboards adjacent to wall to allow access to floor void and joists. 3.) Stuff joist ends with off cuts of flexible woodfibre insulation. 4.) Seal round joists as it penetrates wall. 5.) Install Insulated suspended timber floor from below. 6.) Fix IWI to floor level with EcoBatt to foot. 7.) Intelligent membrane and plasterboard with skim. 8.) Fix floorboards and skirting boards and make sure of air-tightness.

REFERENCE SPECIFICATION:

Before starting work undertake study of form and condition of existing walls and likely resistance to penetrating damp; log requirement of any repairs and/ or additional works to both internal and external condition necessary before installation of new system -e.g. re-pointing or repairs to external render. Internally: Before starting work carry out study of form and condition of the existing walls; draw up schedule of fixtures, finishes and fittings to be removed/relocated in order to install the internal wall insulation system. Attention to be paid to mechanical and electrical services (e.g. radiators, light switches). Refer to detail drawings for treatment of potential cold bridges (e.g. window reveals). All timbers: Before starting work carry out inspection of any structural timbers which enter the wall to be insulated (e.g. floor joists). Report any signs of damp or rot to contract administrator immediately. Record current condition of timbers and moisture content for future reference.

All Expanded polystyrene insulation (EPS): To BS EN 13163. All fixings manufactured in accordance with BS1210. Mineral wool (MW): To BS EN 13162; reaction to fire rating to: BS EN 13501-1

All vapour control layers/ air tightness layer to durability requirements of EN 13984.

Please refer to Approved documents: B (fire safety): B1 section 1 (material alterations)/ B2 section 3 (internal fire spread), and Appendix A (material properties). Doc L: Section 5 and 6 of L1B; including all relevant amendments. Ensure existing joists meet requirements in Approved document A (structural) before starting works.

Parts list

• Internal Wall Insulation System (95mm) [IW02]

  Earthwool Eco batt insulation. \ Thickness 95mm\ Target u-value: 0.3W/m2k. Thermal conductivity: 0.033W/m2k/ 0.130W/mk. GWP<5. \ Fixing: In accordance with manufacturer's recommendations. Supports: EcoStuds - XPS and OSB uprights.

  Contacts:

  Knauf \ ThermoShell Internal Wall Insulation System

• Vapour Control Layer [IW02]

  Intelligent breather membrane. \ Fixing: Laps And Edges: Sealed with vapour-tight adhesive tape. At junctions with party/partition walls, lap under insulated plasterboard. At floor and ceiling junctions ensure is appropriately sealed.

  Contacts:

  OPTION 1.) Pro-clima \ http://www.greenbuildingstore.co.uk/page--pro-clima-interior-membranes-options.html \ Reference: Intello membrane \ OPTION 2.) : Knauf \ http://www.knaufinsulation.co.uk/media/1080123/kine1491dat-thermoshell-vapour-control-layer-datasheet.pdf \ Thermoshell Vapour Control layer

• Draughtex Neoprene Strips [DP02]

  All timber ground floors: draught-proof and seal all timber floors to ensure no air-leaks. Draughtex neoprene strips or timber fillet/ mastic seal between skirting and floor. \ Skirtings and Wall junctions: Seal all junctions and repair any cracks in plaster to ensure no air-leaks. Standard decorators caulk between skirting and wall.

  Contacts:

  Draughtex \ www.draughtex.co.uk \ Draughtex Neoprene Strips

• Double-sided air seal tape [DP09b]

  Tape for junctions critical to air-tightness. 85mm (typical). \ Accesssories: ORCON F sealant and TESCON PRIMER RP (for use on rough/old surfaces to assist adhesion)

  Contacts:

  Pro Clima \ http://www.greenbuildingstore.co.uk/page--pro-clima-airtightness-tapes-options.html \ Contega SL

• External Perimeter Floor Insulation [FL01]

  Extruded Polystyrene (XPS) to BS EN 13164. Suitable for below ground conditions and for application of render. \ Thickness as external wall insulation. Depth: 600mm below internal floor level or to footings. Tight butt joints. \ Thermal conductivity: 0.033W/mK. GWP<5.

  Contacts:

  BASF \ http://www.plasticsportal.net/wa/plasticsEU~en_GB/portal/show/content/literature/styrodur \ Reference: Styrodur 2800C.

• Plasterboard and fixings [IW02]

  Plasterboard components to be installed with IWI system. Knauf Moistureshield/ Wallboard/ Denseshield. Knauf Drywall screws

  Contacts:

  To IWI manufacturers recommendation.

• EcoStud insulated supports IWI system [IW02]

  Vertical supports for IWI batts. Thermally engineered composite of high performance extruded polystyrene bonded to Oriented Strand Board 3 (OSB 3)supports to IWI sheets. Expanded polystyrene insulation (EPS): To BS EN 13163.

  Contacts:

  Knauf Insulation. \ http://www.encon.co.uk/sites/default/files/products/downloads/datasheet-ecostud.pdf \ Reference: EcoStud for Solid walls. (Used in conjunction with Earthwool EcoBatt.)

• Skirting & Wall/Floor junctions [DP04]

  Seal all junctions and repair any cracks in plaster to ensure no air-leaks. \ Standard decorators caulk between skirting and wall. Draughtex neoprene strips or timber fillet/ mastic seal between skirting and floor.

  Contacts:

  Contractors choice \ Reference: decorators caulk. / Draughtex \ www.draughtex.co.uk \ Draughtex Neoprene Strips