Flat roofs

The position of the thermal insulation in relation to the structural roof deck has created two basic categories of roof design:

• Warm roofs

• Cold roofs

A warm roof has the insulation above the structural deck, which is thus kept warm. The waterproof layer is above the insulation and a vapour control layer is placed below the insulation.

An inverted/protected membrane roof is a form of warm roof in which the insulation is placed above the waterproof covering (which also acts as a vapour control layer).

A cold roof has the insulation placed below the structural deck, which thus remains cold. This construction relies on a vapour control layer working effectively, and in tandem with a continuous ventilated airspace to disperse the water vapour to atmosphere before it reaches the cold deck and condenses.

Concrete, timber and metal deck flat roofs can all be designed as warm roofs with a built-up felt or mastic asphalt roof covering. An integral part of a warm deck flat roofing system is the installation of the vapour control layer on the warm side of the insulation.

Rocksilk Krimpact Flat Roof Slab is a high strength, consistent density, rigid, rock mineral wool slab manufactured using Krimpact technology and specifically designed for use in flat roofing.

Rocksilk Krimpact Flat Roof Slab is suitable for use on all types of roof deck and has sufficient compressive strength to be used on warm-deck flat roofs with limited access with concrete, timber or metal decks and subject to light maintenance traffic. If there is a likelihood of more severe traffic occurring, then additional precautions should be considered.

Rocksilk Krimpact Flat Roof Slab is compatible with most PVC, EPDM and other types of mechanically fixed single ply waterproofing membrane systems. The advice of the single ply membrane manufacturer should be sought to confirm compatibility with specific membranes.

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