More have become aware that foam based insulation boards with low or no vapour permeability can cause problems in the longer term for historical roof timbers. Additionally, the breather membranes that are used with them are dangerous to bats. Bats often roost in church roofs and become trapped in the fibres used in the membranes, causing them to die.
Wood fibre sarking boards, such as the UdiTOP insulation system are a very effective and simple way to insulate such roofs. The system is very quick to install, gives good levels of insulation and is very vapour permeable.
Wood fibre insulation is also extremely good at transporting moisture. This allows any moisture that has got in to the structure during the works to be released very quickly after completion, ensuring no damage or decay occurs. It also keeps the roof timbers dry in the longer term by ensuring low humidity in the structure and by preventing moisture accumulation against the timbers.
UdiTOP wood fibre boards have a water repellent surface and so don’t need any membranes to protect them and can be used to replace a breather membrane. Bats are then able to roost without any chance of becoming trapped. Due to the way the wood fibre stores and releases heat it actually creates an environment more suitable for bats, helping preserve these protected creatures.
To ensure airtightness and moisture regulation of the structure, a layer of variable vapour control layer, such as UdiSTEAM 10 plus, should be used under the UdiTOP. The is usually laid on to the existing timber sarking boards, often found forming the internal finish of the roof.
UdiTOP wood fibre sarking boards enable the simple detailing and construction of secret gutters and box gutters behind parapet walls making it an ideal material for use in this area.