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Thermo-loc FR cavity closers

Fire rated cavity closers for eliminating damp and 'cold bridging' around doors, windows and sills available in widths of 50, 75, 90, 100 ,125 and 150mm

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Features & Benefits

  • Supplied in convenient 2.4 metre lengths
  • Simple installation, profiles can be trimmed to required length


  • 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
  • 30 minutes fire rating

Technical Information

  • Provides an effective DPC and thermal barrier between frame, inner and outer wall leaf
  • Exceeds the minimum thermal resistance path of 0.45m²K/W stipulated in Robust Details ‘limited thermal bridging and air leakage’
  • Rigid profile extrusion allows both first and second fix
  • Suitable for all frame and sill positions
  • Integrated & flexible water strip to reduce air leakage
  • Durable and resistant to decay
  • Insulation option to suit your requirements both thermal and fire rated
  • Simple on-site trimming to cope with ‘rogue’ cavity widths
  • Low ECO Points rating


  • Fire rating: Yes- 30 minutes
  • Acoustic performance: N/A
  • Rockfibre mineral wool (FR) insulation: 0.035W/mk
  • Global Warming potential depletion level of less than: 5
  • Insulation zone depletion level:0
  • Satisifies BRE document: Thermal insulation: avoiding risks
  • BRE Green Guide Life Cycle Assessment: A+

Installation Advice

  • Can be used in both first and second fix applications
  • Cut the cavity closer into required lengths allowing the jamb section to overlap the till section and to butt the underside of the lintel
  • In first fix applications the cavity closer should be nailed to the jamb/sill of the door or window frame and the whole assembly built in as work proceeds. Alternatively the closer can be build in sections using fixing ties as work proceeds or pre built to act as an opening former by using a timber brace
  • 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 using a sharp knife
  • Joining 'off cut' sections should not be carried out for FR range

How to Order

  • Establish the cavity width and select the correct cavity closer width, or the next size up to ensure the cavity can be closed
  • In jamb and sill applications, first estimate the total length of the cavity closer required, then order the correct number of lengths so no joint pieces
  • Fixing ties are available for secure fixing if required. Allow for ties fitted at 450mm centres

Quality and Material

  • BBA Approved Certificate No. 07/4501
  • Satisfies NHBC Standards
  • Manufactured to BS EN ISO 9001:2008
  • Complies with Building Regulation Approved Documents C, L1 & L2
  • Complies with Robust Details ‘limited thermal bridging and air leakage’
  • Complies with the Scottish Building Standards ‘Technical handbook’
  • Rigid profile with extruded white UPVC
  • Rockfibre mineral wool (FR) insulation
  • Wider cavities are available to special order

Product Range

Description Cavity width Length Pack Product code
Thermo-loc FR 50mm 2.4m 5 CC2.4 FR/50
Thermo-loc FR 65mm 2.4m 5 CC2.4 FR/65
Thermo-loc FR 75mm 2.4m 5 CC2.4 FR/75
Thermo-loc FR 100m 2.4m 5 CC2.4 FR/100
Fixing tie     30 CCFIX
  • nbs plus
  • riba

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