tar and gravel
A roof covering with gravel or small stones laid over a tar layer, commonly used on flat roofs.
Tar and gravel is a common roofing material, especially for flat roofs (including common variants) which uses a base layer of tar made from organic resins or coal byproducts, with a layer of gravel or small stones (such as smooth river stones) on top to ballast the tar. It is heavier than a simple tar roof, and sometimes requires structural reinforcement.
Gravel is commonly considered to add aesthetic appeal to a tar roof, making it more attractive if people have to look down on it. It also serves as a flame retardant.
The stone layer is part of the covering arrangement, which distinguishes this material from exposed tar roofing. The gravel does not form a continuous stone slab; it is a layer of separate small stones over the tar.
Related definitions
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aluminum sheeting
A roof covering formed from large sheets or slats of aluminum, commonly interlocked along their edges. -
asbestos sheeting
A roof covering of large asbestos-containing sheets, typically asbestos cement and often corrugated. -
asbestos shingles
A roof covering of small overlapping asbestos-containing shingles, typically made from asbestos cement. -
asphalt sheeting
A roof covering of large continuous membrane sheets coated on one or both sides with asphalt or tar. -
asphalt shingles
A roof covering of small overlapping asphalt-coated units, commonly reinforced with fiberglass or organic felt. -
brick
A roof covering with an outer layer of small fired masonry blocks, usually joined by mortar. -
ceramic tiles
A roof covering of baked clay or similar ceramic tiles, usually overlapping or interlocking on a sloping roof. -
concrete slab
A roof covering with a continuous, exposed concrete surface formed from precast or cast-in-place concrete. -
concrete tiles
Roofing made from tile or shingles of concrete, often reinforced with fiberglass. -
copper sheeting
A roof covering of large copper sheets or slats joined together, excluding small overlapping copper shingles. -
fabric
A roof covering formed from suspended cloth or a similar flexible, tent-like sheet material. -
fiberglass sheeting
A roof covering of rigid plastic sheets or panels reinforced with glass fibers, often formed with corrugations. -
glass
Roofing made of glass, either as an opaque coating or in the form of an extended skylight. -
iron sheeting
A roof covering of large iron sheets or slats joined together, excluding small overlapping iron shingles. -
metal shingles
A roof covering of small, overlapping rolled-metal plates arranged in successive courses. -
slate
A roof covering made from pieces of natural slate split into thin sheets, usually laid in overlapping courses. -
sod
A roof covering of living grass rooted in soil, including lawns over underground buildings. -
steel sheeting
A roof covering of large steel sheets or slats joined together, often corrugated or shaped to resemble tiles. -
stone slab
A roof covering of natural stone in large slabs or masses, excluding small stone tiles and shingles. -
synthetic membrane
A roof covering formed from sheets of plastic, rubber, or similar synthetic material joined into a watertight layer. -
tar
A roof surface coated with tar, directly or on a fabric or felt carrier, with any underlying wood fully obscured. -
thatch
A roof covering formed from thick overlapping mats of cut grasses or other plant stalks. -
wood planks
A roof covering of wooden boards fitted together, normally in parallel, with possible overlap at their joints. -
wood shingles
A roof covering of small wooden plates laid in overlapping courses, generally on a sloping roof.