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Thermal insulation for use at the junction between the pitched roof and the top of the cavity wall. The requirement for ARC Eaves Insulator elevated from the problem of heat loss through the roof membrane at the junction between the pitched roof and the top of the cavity wall.

The nature of the shape of this part of the dwelling lends itself to difficulties in access for construction workers to provide adequate and consistent insulation to prevent heat loss.

Traditional methods of filling this ‘triangular cavity’ are to apply a mineral fibre product manually over the  ceiling trusses, forcing it into the narrow gap at this junction. This method of filling this ‘triangular cavity’ can be problematic for the construction worker. Calculating the amount of mineral fibre required is difficult and knowing how much compression is required to achieve an effective fill results in inconsistencies in insulation and therefore the heat loss achieved.


Eaves insulator designed to be easily installed using the same method as a standard eaves tray. The stalk of the insulation is placed into the top of the external wall cavity, with care being necessary to ensure a snug fit.

The circular overlap of the insulation is pushed in-between the roof trusses to rest at ceiling level. The eaves tray can then be mechanically fixed to the roof trusses.

Features and benefits:

  • Ensures that junction detail between wall plate and ceiling is fully insulated.
  • Minimizes cold bridging.
  • Compatible with ventilation openings of 10 000 and 25 000 mm²/m.
  • Available to fit 600 mm rafter centres.
  • Can be used in conjunction with all ventilated fascia and soffit designs.
  • Manufactured under ISO 9001- and ISO 14001-certified 'Quality and Environmental Systems'.

General information




Glass mineral wool


600 mm

900 mm


600 mm


Pr_25_57_06_53 Mineral wool insulationPrimary


F30/18 Cavity closers

F30/180 Cavity closers

Specification data - Mineral wool insulation

Width (nominal)


Manufacturer guidance

To suit 600 mm rafter centres.

Fire performance

To BS EN 13501-1, Euroclass A1.


Glass fibre mineral wool.


0.035 W/mK.


600 mm.


Eaves Insulator Data Sheet

Eaves Insulator Data Sheet