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Thermo-loc Platinum+

Cavity closers for eliminating damp and cold bridging around doors, windows, and sills.

Use cases:

  • 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

For more information call 01405 765567 Free next day delivery *

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Features & Benefits

  • Effective DPC and thermal barrier between frame, inner and outer wall leaf
  • Thermal conductivity of 0.031W/m2k
  • 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
  • Available fully rebated - Check reveal (single flange)


Technical Information

  • 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 (check reveals) for zones Very Severe”
  • With reference to insulation, the products in this range do not use, contain or produce Urea Formaldehyde, CFC’s or indeed any of the so called soft CFC’s, ie. HCFC’s & HFA’s. They have an ozone depletion potential of zero and global warming potential of less than 5 and complies with BS EN 13163.


  • 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

Material and colour choice

  • Rigid profile extruded in UPVC
  • Platinum expanded Polystyrene insulation 0.031W/mk
  • Multi 100mm, Multi 100mm CR and fixed cavities
  • 2.4m lengths

Installation advice

  • The accredited construction detail published by DCLG require a minimum overlap of 30mm between the window frame and cavity closer
  • Cutintorequiredlengthsallowingjambsectiontooverlapthesillsectionbycutting away parts of the fixing flange and to 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, or alternatively the insulation can be trimmed to fit using a sharp knife
  • Fixing nails to the flanges are recommended to ensure a secure fit
  • Cavity insulation should butt tightly to the cavity closer

How to order

  • Establish the cavity width and select the correct cavity closer width to ensure the cavity can be closed
  • In jamb and sill applications, estimate the total length of cavity closer required and order the correct number of 2.4 metre lengths ensuring no joint pieces

Bill of quantity

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.PP2.4/50 (Thermo-loc Platinum+, Expanded Polystyrene, 2.4m, 50mm)
  • nbs plus
  • riba

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