|Deniimmutty||Дата: Среда, 2013-08-07, 15:53 | Сообщение # 1|
Metal roofs (photo 4) are noncombustible and can often be cut with an ax or power saw at the same time as the wood-roof sheathing to which they are usually attached for vertical ventilation. They provide precarious footing when intact and become slippery when wet. Metal roofing materials are sometimes applied over other types of original roofing materials when they have reached the end of their effective life.
Both wood and asphalt shingles and the wood-roof sheathing to which they are attached are easy to cut with an ax or power saw, making vertical ventilation an option in structures with these types of roofs. http://buildconst.site11.com
Slates and tiles are difficult to cut with an ax or power saw. They must be broken with a maul or an ax for access to the wood-roof sheathing to which they are usually attached, for vertical ventilation. http://construction.uphero.com Slates and tiles are much heavier than wood or asphalt shingles or metal roofs, and the supporting structure must be designed and built to support this weight (dead load).