Sarking Board Roof Detail

Product will differ from image slightly as it is rough sawn.

Sarking board roof detail.

Underneath these battens you will find your counter battens running vertically and beneath these a breather membrane. Sarking boards with a gap of 2 3 mm between each one. The use of bituminous under slate felt or other vapour barriers under the slates which prevent water vapour movement can lead to high humidity in the roof space and can have detrimental effects on the roof in the long term. An entire re roofing process would need to take place to add sarking boards where any roof tiles or slates would need to be removed and then replaced over the top.

Insulation sitting either between and under or between and over the rafters. A typical roof build up that contains sarking is as follows from the bottom. Roof tiles or other covering. 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.

The apb effectively extends the barrier provided by sarking out to the guttering. If your tiles are laid without counter battens rainwater could pass between the tiles and get stuck behind the tiling batten building up a pool of water over time. If the sarking boards are damaged and require renewal they should be re laid with a small gap to allow for ventilation. I have two views on this but thought i would get a collective opinion.

Roof sarking improves performance and comfort by providing the following benefits. Helps protect your home from unseen mould growth or even worse ceiling staining or permanent damage which can result from the entry of storm driven rain into the roof cavity. Hi all our roof will be metal raised seam it is supposed to sit on 18mm osb which i don t plan on doing i m planning on using a sarking board just like our scottish neighbours do would you use treated timber or just rough sawn. Next anti ponding board apb is installed underneath the sarking at the edges of the roof.

Tiles are then laid out. A sealed roof system is achievable using a vapour permeable underlay such as monarperm 700 if a minimum 2mm gap can be guaranteed between the sarking boards which should be a minimum of 150mm wide. The purpose of the anti ponding board is to prevent water from pooling underneath the tiles at the outer edge of the roof. Roof tiles are usually laid horizontally attached to timber tiling battens.