Flat roofing isn’t really flat; it’s a really low slope—between 1/4 to 1/2 in. per foot—so that it drains water. however, such an occasional slope holds snow and water for much longer than a steeply pitched roof and thus desires a really completely different material to remain watertight. whereas commonplace sloping roofs usually have shingles that are overlapped like fish scales in order that water slides over them, a flat roof is meant as a continual, or monolithic, surface which will hold some standing water for a restricted time. flat roofing bristol is popular for flat roofing.
There are 3 main varieties of flat roof systems:
- Membrane or single-ply
- Built-up roofing (BUR)
- Modified hydrocarbon (MBR)
- Membrane (Single-Ply) Roofing
There are many varieties of membrane roofing materials, together with rubber and plastic formulations. the foremost common sort used for residential flat roofing is EPDM (ethylene gas diene monomer), an artificial rubber sheet material that’s additionally unremarkably used as a pool liner.
Membrane roofing consists of a layer of insulation board lidded by sheets (the membrane) of EPDM rubber or alternative material. The EPDM membrane may be loose-laid and command in situ with ballast, like stream rock or masonry pavers. The membrane can even be mounted or affixed to the insulation layer.
- Repairs are comparatively straightforward and inexpensive; householders could also be able to build some repairs themselves.
- The roof deck doesn’t would like reinforcement as a result of EPDM roofing is light-weight.
- Leaks are terribly rare with EPDM roofing provided no surface harm happens.
- EPDM roofing will retain heat to lower heating bills; alternative varieties of membrane roofing will replicate heat to stay the house cooler.
- Roof penetrations, like pipes, HVAC systems, and chimneys, build installation harder and costly; penetrations may be a supply of leaks if not flashed properly.
- Membranes may be perforated by falling branches, pedestrian traffic throughout installation or maintenance, or storm harm, resulting in leaks.
- Seams between membrane sheets, whereas sealed, are common areas for leaks.
Built-Up Roofing (BUR)
Built-up roofing (BUR) was the foremost common sort of flat roof before changed hydrocarbon and membrane roofing were developed. BUR consists of many layers: a bottom layer or 2 of insulation board, multiple intermediate layers of tar or asphalt alternated with layers of roofing felt, and a high layer of gravel. The result’s a thick, tough, seamless roof assembly that’s extremely immune to harm.
While settled roofing continues to be utilized in some industrial applications, it’s not a standard roof sort for homes, primarily thanks to its weight and thickness still because of the robust odors and messes it creates throughout the installation.
- It’s simple to get rid of layers once repairing or resurfacing the roof.
- The gravel in settled roofing makes it extremely immune to traditional pedestrian traffic.
- Installing BUR is slow and labor-intensive, thanks to the numerous layers and materials concerned.
- Potentially unsafe fumes and vapors are emitted throughout the installation.
- The roofing assembly is incredibly significant and infrequently needs that roof joists are reinforced before it’s put in.
- Built-up roofing isn’t versatile in cold temperatures, creating it liable to harm.
Modified hydrocarbon Roofing
Modified hydrocarbon roofing (MBR) was developed within the early Nineteen Sixties as a lighter-weight various to BUR. It additionally comes while not a lot of the mess, heat, and smell related to putting in BUR. changed hydrocarbon roofing could be a versatile, asphalt-based material with a mineral high coating, kind of like ancient asphalt shingles. It comes in rolled sheets that are three feet wide and up to thirty-six feet long. The sheets are rolled onto the roof atop a base sheet membrane.