9mm x 250mm Deeplas Fascia Board (also known as Cover Board) are used in the exterior of the building and forms part of the roofline. The board is measured externally, ie. a 250mm Cover board will cover 241mm of existing timber.
The 9mm fascia boards should only be used for refurbishment and renovation when fixed on existing sound timber. The 9mm board should not be fixed directly to a rafter feet. If existing wood is damp, rotten or if its condition is in any doubt, use the 16mm fascia board. The 9mm board can support roof tiles where an adequate backing board is used.