| 摘要 |
Waterproof underlay for a tiled roof is made from a sheet of polyethylene film which is covered on one side with a layer of polyester or polyamide fibres. The underlay has a thickness of about 1.8 mm and weighs about 150 g/square metre. Pref. the underlay has rows of holes spaced apart by a distance of 10 to 15 mm using a needle of about 0.6 mm diameter. The polyethylene film is pref. about 0.06 mm thick and is coated with adhesive to receive the fibre layer. The holes are made by inserting the needle from the coated surface towards the uncoated surface. |
