Sarking Board Roof Detail

A thicker water resistant sarking board which is a combination of pavatherm and isolair for externally insulating roofs and masonry or timber frame walls behind a ventilated façade.

Sarking board roof detail.

Sarking boards are softwood boards generally about 150 mm wide that are attached to the rafters of a pitched roof to give extra strength to the overall structure of a building. Counter battens are wooden strips that are installed vertically over pitched roofs to which horizontal tiling battens are attached. They are used to allow rainwater to pass off the tiles and away from your roof. Sarking is a board which is normally 150mm x 18mm x 4800 and we use it to cover a roof before felting we use it a lot in scotland either that or 9mm or 11mm osb the rip of wood normally osb which supports the felt is called a felt support.

They needn t be used in every application and instead their use largely depends on where in the country you are based and what type of construction you are building. All of these elements should be considered when repairs are being specified and carried out. The moisture content of the sarking will vary with the seasons and the underlay being in direct contact needs to allow moisture to pass through it. The sarking board itself is a barrier to the migration of water vapour and in most situations will require the provision of ventilation to the roof space in accordance with bs5534 bs5250 2011.

Sarking boards were always used with slate in scotland and it s become standard practice there to use sarking on any roof now. Similar to hofatex kombi. Our new build bungalow in scotland had a tiled roof bit still had plywood sarking. They are typically around 150 mm wide and are used to provide additional support and strength to the overall structure.

Let s go into a bit more detail. Recommended for use in warmer climates. Thermoseal reflective foil roof sarking is a non permeable vapour barrier to reduce the transmission of moisture into the home and contribute r value to the roof system.