Liquid roofing
Encyclopedia
Liquid Roofing is the process of waterproofing
a roof
by the application of a specialist liquid
roof coating
. It is suited to all types of roof including flat
, pitched
and domed.
History=
The concept of liquid roofing has existed since (at least) the early 1800s, when natural bitumen was combined with jute
, straw
, rag felt
and other man made materials to provide a waterproofing solution for roofs. In the early twentieth century the manufacture of liquid roof coatings became a commercial activity, with the earliest coatings being based on liquefied rubber. The 1960s and 1970s saw the introduction of acrylics, acrylic emulsions, styrene butadienes
and unsaturated polyester
s, which led to improved quality and durability of the coatings. In 1975, the first water based elastomeric roof coatings were introduced. In the late 1980s, single component moisture-cured polyurethane
coatings were developed and remain the basis of the majority of today's cold liquid applied roof coating technologies.
Concept=
Liquid roofing involves the application of a monolithic, fully bonded, liquid
based coating to a roof
. The coating cures to form a rubber-like elastomeric waterproof membrane, capable of stretching and returning to its original shape without damage. Such coating systems are usually reinforced with secondary
materials such as glass-reinforced plastic
to provide additional tensile strength
. The coatings can be applied over most traditional roofing materials including, felt
, asphalt
, bitumen and concrete
.
, asphalt
and bitumen membranes, liquid roofing does not involve hot works. Hot work on roofs is an extremely high-risk process, that poses a significant fire risk to contractors as well as the building and its occupants. The coating material used in the liquid roofing process is applied cold, thus negating any fire risk.
External links=
Waterproofing
Waterproof or water-resistant describes objects relatively unaffected by water or resisting the ingress of water under specified conditions. Such items may be used in wet environments or under water to specified depths...
a roof
Roof
A roof is the covering on the uppermost part of a building. A roof protects the building and its contents from the effects of weather. Structures that require roofs range from a letter box to a cathedral or stadium, dwellings being the most numerous....
by the application of a specialist liquid
Liquid
Liquid is one of the three classical states of matter . Like a gas, a liquid is able to flow and take the shape of a container. Some liquids resist compression, while others can be compressed. Unlike a gas, a liquid does not disperse to fill every space of a container, and maintains a fairly...
roof coating
Roof coating
A roof coating is a monolithic, fully adhered, fluid applied roofing membrane. It has elastic properties that allows it to stretch and return to their original shape without damage....
. It is suited to all types of roof including flat
Flat roof
A flat roof is a type of covering of a building. In contrast to the sloped form of a roof, a flat roof is horizontal or nearly horizontal. Materials that cover flat roofs typically allow the water to run off freely from a very slight inclination....
, pitched
Pitched roof
A pitched roof is a roof for which one or more roof surfaces is pitched more than 10 degrees, and alternately a roof with two slopes that meet at a central ridge. Some definitions are even more general, including any roof with a sloping surface or surfaces....
and domed.
History=
The concept of liquid roofing has existed since (at least) the early 1800s, when natural bitumen was combined with jute
Jute
Jute is a long, soft, shiny vegetable fibre that can be spun into coarse, strong threads. It is produced from plants in the genus Corchorus, which has been classified in the family Tiliaceae, or more recently in Malvaceae....
, straw
Straw
Straw is an agricultural by-product, the dry stalks of cereal plants, after the grain and chaff have been removed. Straw makes up about half of the yield of cereal crops such as barley, oats, rice, rye and wheat. It has many uses, including fuel, livestock bedding and fodder, thatching and...
, rag felt
Felt
Felt is a non-woven cloth that is produced by matting, condensing and pressing woollen fibres. While some types of felt are very soft, some are tough enough to form construction materials. Felt can be of any colour, and made into any shape or size....
and other man made materials to provide a waterproofing solution for roofs. In the early twentieth century the manufacture of liquid roof coatings became a commercial activity, with the earliest coatings being based on liquefied rubber. The 1960s and 1970s saw the introduction of acrylics, acrylic emulsions, styrene butadienes
Styrene-butadiene
Styrene-Butadiene or Styrene-Butadiene-Rubber is a synthetic rubber copolymer consisting of styrene and butadiene. It has good abrasion resistance and good aging stability when protected by additives, and is widely used in car tires, where it may be blended with natural rubber...
and unsaturated polyester
Polyester
Polyester is a category of polymers which contain the ester functional group in their main chain. Although there are many polyesters, the term "polyester" as a specific material most commonly refers to polyethylene terephthalate...
s, which led to improved quality and durability of the coatings. In 1975, the first water based elastomeric roof coatings were introduced. In the late 1980s, single component moisture-cured polyurethane
Polyurethane
A polyurethane is any polymer composed of a chain of organic units joined by carbamate links. Polyurethane polymers are formed through step-growth polymerization, by reacting a monomer with another monomer in the presence of a catalyst.Polyurethanes are...
coatings were developed and remain the basis of the majority of today's cold liquid applied roof coating technologies.
Concept=
Liquid roofing involves the application of a monolithic, fully bonded, liquid
Liquid
Liquid is one of the three classical states of matter . Like a gas, a liquid is able to flow and take the shape of a container. Some liquids resist compression, while others can be compressed. Unlike a gas, a liquid does not disperse to fill every space of a container, and maintains a fairly...
based coating to a roof
Roof
A roof is the covering on the uppermost part of a building. A roof protects the building and its contents from the effects of weather. Structures that require roofs range from a letter box to a cathedral or stadium, dwellings being the most numerous....
. The coating cures to form a rubber-like elastomeric waterproof membrane, capable of stretching and returning to its original shape without damage. Such coating systems are usually reinforced with secondary
Secondary
Secondary is an adjective meaning "second" or "second hand". It may refer to:* The group of defensive backs in American football and Canadian football* An obsolete name for the Mesozoic in geosciences...
materials such as glass-reinforced plastic
Glass-reinforced plastic
Fiberglass , is a fiber reinforced polymer made of a plastic matrix reinforced by fine fibers of glass. It is also known as GFK ....
to provide additional tensile strength
Tensile strength
Ultimate tensile strength , often shortened to tensile strength or ultimate strength, is the maximum stress that a material can withstand while being stretched or pulled before necking, which is when the specimen's cross-section starts to significantly contract...
. The coatings can be applied over most traditional roofing materials including, felt
Felt
Felt is a non-woven cloth that is produced by matting, condensing and pressing woollen fibres. While some types of felt are very soft, some are tough enough to form construction materials. Felt can be of any colour, and made into any shape or size....
, asphalt
Asphalt
Asphalt or , also known as bitumen, is a sticky, black and highly viscous liquid or semi-solid that is present in most crude petroleums and in some natural deposits, it is a substance classed as a pitch...
, bitumen and concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
.
Cost effectiveness
The process of liquid roofing provides a cost effective method of making a new or existing roof waterproof. It can deliver up to 25 years performance depending on the coating system employed. It is estimated that liquid roofing is 70% less expensive than overall roof replacement in refurbishment situations.High performance
Liquid roofing can be undertaken with high performance materials. Many of the products used in the liquid roofing process have been independently tested and their performance verified. In the United Kingdom, the leading testing and approvals house the British Board of Agrément (BBA) has been issuing approvals for liquid roofing systems since 1975.Safety
Unlike the installation processes of feltFelt
Felt is a non-woven cloth that is produced by matting, condensing and pressing woollen fibres. While some types of felt are very soft, some are tough enough to form construction materials. Felt can be of any colour, and made into any shape or size....
, asphalt
Asphalt
Asphalt or , also known as bitumen, is a sticky, black and highly viscous liquid or semi-solid that is present in most crude petroleums and in some natural deposits, it is a substance classed as a pitch...
and bitumen membranes, liquid roofing does not involve hot works. Hot work on roofs is an extremely high-risk process, that poses a significant fire risk to contractors as well as the building and its occupants. The coating material used in the liquid roofing process is applied cold, thus negating any fire risk.
External links=
- Liquid Roofing & Waterproofing Association – UK trade association for roof coatings manufacturers and contractors.
- RIBA Product Selector – Information on liquid roofing products available from a number of UK manufacturers.
- British Coatings Federation – British Coatings Federation.
- Kemper System - Global manufacturer of liquid roofing.
- Tor Coatings – UK manufacturer of roof coatings.
- Liquid Plastics – UK manufacturer of roof coatings.
- Liquid Roofing – UK installer of 3M liquid roof coatings.