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555 Thermal Cavity Closer

An insulated cavity closer designed to be used as a dpc at door and window openings in cavity wall construction. It consists of a tissue-faced rock fibre slab, laminated to black polyethylene DPC material, which forms a 40 mm flange on each side of the insulation and a 100 mm flange at the bottom edge.


  • Thermal bridging solution.
  • Strong yet flexible.


The cavity closer should be fitted as the wall constructed, before the installation of door and window frames. It should be fitted with the dpc face against the inner face of the outer leaf of masonry. The outer flange should be folded back against the reveal when the frame is fitted.

General information
Uniclass 2015
Pr_25_80_80_79 Sleeved mineral wool cavity barriersPrimary

F30/18 Cavity closers

F30/180 Cavity closers

Specification data - Sleeved mineral wool cavity barriers
Product Reference

555 Thermal Cavity Closer


100 mm

150 mm

190 mm


20 mm

Thermal resistance: 0.57 m²K/W.

50 mm

Thermal resistance: 1.42 m²K/W.

Standard product features


  • Insulation: 1200 mm.
  • Unit: 1300 mm.

Thermal conductivity of insulation:

0.35 W/mK.

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