Thermo-loc Platinum Multi Cavity Closer

Cavity closers designed to eliminate damp and cold bridging around doors, windows, and sills.

Suitable for a range of cavity sizes up to 150mm by easily cutting to size using the pre-cut grooves. 20mm insulation thickness. Compliant with Building Regulation Approved Documents C, L1 and L2 and satisfies BRE document ‘Thermal Insulation: avoiding risks’. View LABC certificate.


  • To close the cavity at external doors, window jambs and sills
  • To provide thermal insulation and prevent ‘cold bridging’
  • To provide a DPC at external doors, window jambs or sills
  • Suitable for cavities up to 150mm

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Product Information

Thermo-loc Platinum Multi

DescriptionCavity WidthLengthPack QuantityLead TimeProduct Code
Thermo-loc Platinum Multi 50-100mm50-100mm2.4m10Next working dayCC2.4PPS/MULTI100
Thermo-loc Platinum Multi 100-150mm 100-150mm2.4m10Next working dayCC2.4PPS/MULTI150

  • Provides an effective DPC and thermal barrier between frame, inner and outer wall leaf
  • Thermal conductivity of 0.031W/mk
  • Exceeds the minimum thermal resistance path of 0.45m2 K/W stipulated in accredited construction details
  • Rigid profile extrusion allows second fix
  • Durable and resistant to decay
  • Simple on-site trimming to cope with ‘rogue’ cavity widths
  • Global warming potential of less than 5
  • Ozone depletion potential of zero
  • Manufactured to BS EN ISO 9001 and BS EN ISO 14001
  • Complies with Building Regulation Approved Documents C, L1 & L2
  • Satisfies BRE document ‘Thermal insulation: avoiding risks’
  • Meets all relevant British Standards
  • Satisfies NHBC standards
  • Rigid profile extruded in UPVC. Platinum expanded Polystyrene insulation 0.031W/mk. Multi 100mm & Multi 150mm cavities. 2.4m lengths.
  • Establish the cavity width and select the correct cavity closer width to ensure the cavity can be closed.
  • In jamb and sill applications, first estimate the total length of cavity closer required, then order the correct number of individual 2.4 metre lengths so no joint pieces.
  • The accredited construction detail published by DCLG require a minimum overlap of 30mm between the window frame and cavity closer.
  • Cut into required lengths allowing the jamb section to overlap the sill section by cutting away parts of the fixing flange and butt the underside of the lintel.
  • For second fix applications, the cavity closer is pushed into the open cavity after building work is complete. The compressible nature of the exposed insulation material is used to create a friction fit in the cavity, alternatively the insulation can be trimmed to fit using a sharp knife.
  • Fixing nails to the flanges are recommended to ensure a secure fit.
  • BRE Document ‘Thermal insulation: avoiding risks’ stipulate “When a window or door frame is set back behind the inner face of a dense outer masonry leaf, it should overlap an insulated closer by a minimum of 30mm for BRE exposure zones Sheltered to Severe; but fully rebated for zones Very Severe”.
  • With reference to insulation, the products in this range do not use, contain or produce Urea Formaldehyde, CFCs or indeed any of the so-called soft CFCs, i.e., HCFCs & HFAs. They have an ozone depletion potential of zero and global warming potential of less than 5 and complies with BS EN 13163.

F30 Accessories/sundry items for brick/block/stone walling window jambs and sills

  • To extend not less than 150mm beyond ends of lintels/bridgings.
  • Manufacturer: Timloc Building Products, Ozone Park, Howden, East Yorks. DN14 7SD. T: 01405 765 567 W:
  • Reference: eg. CC2.4PPS/Multi100 (Thermo-loc Platinum Multi, Expanded Polystyrene, 2.4m, multi cavity up to 100mm)

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