Why Do Buildings Have Rocks On The Roof

The stones force it to stay put.

Why do buildings have rocks on the roof.

In the summer it gets pretty soft and if left to its own devices would flow to the lowest point on the roof. Pea gravel is sometimes placed on top of a smooth bur asphalt roof to protect the roof. Yes it is for wind lift. To keep the roofing material in place to protect the roofing material from uv radiation and thus prolonging its lifespan for that the roof must be completely covered with stones and pebbles to prevent snow from sliding off a sloped roof but for this larger stones are often used.

This surfacing keeps the felts protected from the sun s uv rays which damage the felts over time. Remember trad italian roofs have much bigger overhangs on the eaves the bit which overhangs the long sides of a pitched roof and also on the verges which overhang the gables. The only purpose of rock on a membrane roof is to hold the roof system down. It s also a bit of an aesthetic nicety on more modern roofs just for the crack as it were.

Out here in california those rocks absorb the heat and reflect the sun s rays most houses fitted with the low wing have no attic space. Tar has a low melting point. In a typical tar and gravel roof which by the way is gradually being supplanted by gravelless roof systems you put down a layer of tar paper then tar and finally gravel. Various types of rock are embedded into asphalt roofs to add strength to the roof and help it last longer.

Additional benefits of ballast on a flat roof. Rocks gravel are for ballast weight to hold the roofing material on and to reflect heat and sunlight to prolong the life of the roof. Afaik the main purpose of stones and pebbles on roofs is. As the white rock material reflects sun rays the forced air is enough to keep the home from becoming unbearable during the summer months.

Ballasted flat roofs are a popular choice especially for commercial buildings. It aided in keeping the house sturdy in the face of earthquakes and wind. Gravel surfacing on a asphalt built up roof system is embedded in asphalt above the felt plies.