The greatest cause of failure for a flat roof is the inability to correct minor deterioration and defects, in their early stages. Problems caused by weather or natural disasters, or by age, require roofing contractors and flat roof repair. A contractor will advise the building owner whether to repair or replace and will supervise the implementation of engineering plans, as needed.
There are four basic types of coverings for roofs. Asphalt roll consists of one layer of an asphalt-saturated base felts, made of either organic material or fibreglass, which is applied over roof felt, using nails and cold asphalt cement. After the covering is used, the seams are covered with roofing compound. In general, asphalt roll roofs last around ten years before requiring replacement.
Multiple-ply is another covering. Multiple-ply consists of overlapped rolls of coated felts or mats, interspersed with layers of a cementations substance called bitumen. The rolls are then surfaced with a granular roofing sheet, ballast, or tile pavers, to prevent weathering of the underlying materials. Weight, which consists of crushed stone, embedded in asphalt or coal tar, makes roof inspection challenging because it covers up seams.
Single-ply is the most recently developed method. The single sheet of material may consist of modified bitumen, rubberized asphalt, elastomer membranes, EPDM, or PVC. The sheet may self-adhere, install with hot asphalt, or fix by heating the underside of the sheet with a propane torch. In most cases, single-ply comes with a ten to twelve year warranty, and single-ply is currently used to replace worn-out multiple-ply roofs.
An old but long-lasting type is called flat seam. With flat seam, roofs are covered with sheet metal, which is soldered flush at the joints. The most durable metals are copper, lead-coated copper, and terne-coated stainless steel. Other materials, like galvanized iron, must regularly be painted to prevent corrosion. All metal surfaces may become pitted or perforated when exposed to the elements.
Building owners should inspect flat roofs regularly. The National Roofing Contractors Association suggests checking twice per year, in spring and autumn, and inspecting after rain, to see how water is draining away from the structure. Investigators should note covering problems, related blistering, cracking, rupturing, or loosening, as well as drainage problems, like standing water, clogged drains and gutters and bent or missing drain covers.
Before hiring a contractor, owners should obtain three comparable bids. The contractors asked to bid on the project should have installation experience and a reputation for excellent workmanship. Also, contractors should be able to provide clear guidance on the pros and cons of various roofing materials. Additionally, contractors should work with an architect or engineer, to design a system with built-in backups for failures.
Roofing contractors and flat roof repair become necessary when time and nature cause materials to deteriorate. Regular inspection and correction of minor defects will prevent major repairs, and major expenses, before the end of the expected lifespan. When a roof does need to be replaced, an experienced contractor will be able to offer advice and design assistance, for a reasonable rate.