Waterproof Layer
The condition of the waterproof layer must be checked. Whilst ROOFMATE™ boards will protect an existing layer, and thus increase its life expectancy, they are not a cure for failure of the waterproof layer.
Localised defects in a waterproof layer, which otherwise is in good condition, must be repaired.
A waterproof layer which is near the end of its useful life may be overlaid with a new waterproof layer. Where a roof has no drainage falls the waterproof layer should be to a tanking specification.
Small penetrations such as screed vents and cable ducts require careful detailing: it may be preferable to eliminate many existing features and make good the waterproofing locally.
Existing bitumen felt may have a bonded covering of stone chippings. Before overlaying with ROOFMATE boards sweep off all loose chippings and lay a cushioning layer, such as 5 mm foamed polyethylene sheet.
