Built-up roofing is among the oldest flat roofing construction methods, and it’s still among the most common methods of roofing. Installation of BUR starts off with moisture and vapour barriers being installed over the basic roofing frame. The following step will be installing layers of bitumen which are alternated with waterproof elements. These waterproof elements may consist of fiberglass sheets, roofing fabrics or tar paper. The bitumen mixture comprises of hot gravel and tar, but may also contain other cumulative materials. BUR roofing measured in terms of the number of plies or layers that it contains, with higher numbers signifying higher quality installations.
Membrane roofs are among the longest lasting and most water resistant types of roofs available on the market. They made from PVC sheets, rubber and or thermoplastics with each sheet ranging between 30 and 60 mm in thickness. Membrane roofing sheets are directly installed over the roofing structure without the need for installing a separate vapour or moisture barrier. Insulation may also be placed under the membrane in order to provide some form of thermal resistance. The membranes can then be attached in any of the two ways. They can be treated with a special sealer that enables the sheets to chemically bond or they can be heated so that the seams melt together. Any of these methods when used will help create a neat and seamless installation which is very important and useful at keeping the building free from water.
Spray Foam Roofs
Spray foam roofing is another method of roofing that uses polyurethane foam that bonds with the roof and at the same time forming a protective layer. This roofing method begins with sheets of firm foam insulation which is fastened to the roof structure. The foam solution is then mixed and applied to the roof using a spray gun. The thickness of the foam layer varies across the roof surface in order to permit proper drainage. To ensure that the foam roof remains reliable and effective, an elastomeric coating is applied over the surface. This coating will also add some additional water resistance properties which are also useful in preventing the spread of fires in cases of emergencies. To enhance the final appearance of the roof, sand and other cumulative materials may be mixed onto the top of the surface layer.
These are the most common and popular methods of flat roofing. Having stood the test of time and endurance, they are widely regarded by most roofing professionals.