Gravel roof
A gravel roof is a flat roof on which gravel has been piled. "Gravel roof" is a colloquial term that does not describe the actual type of roof sealing.
The gravel layer, which is usually at least 5 cm thick, serves as protection against UV radiation and heat for the sealing membrane and thus slows down its aging. In addition, it can be used to weigh down the sealing membrane, which otherwise would have to be additionally fastened in order not to be lifted by the suction effect of the wind. In the case of tall buildings, however, gravel can be insufficient, as the stronger wind at high altitude can blow the stones away.
Furthermore, a layer of gravel can serve as fire protection against fire flashover from neighboring higher components. With a layer of min. 5 cm of gravel, a flat roof in accordance with DIN 4102 is considered to be "hard roofing", regardless of the sealing material, and is therefore resistant to flying sparks and radiant heat.
A protective fleece is often laid under the gravel in order to prevent damage to the seal from penetrated sharp-edged pebbles.
A pressed gravel roof is a variant of the flat roof with bituminous waterproofing that is no longer in use today, in which gravel was rolled into a hot bitumen layer.
Individual evidence
- ↑ Refurbishment goes to school ( memento from November 19, 2015 in the Internet Archive ) in Dachbau-Magazin (p. 23)