Roof defects often point to the cause of roof failure. Every type of defect normally arises from a specific cause. Knowledge of the origin of these defects goes a long way in managing the errors that may shorten the roof’s lifespan. To develop remedies to the roof defects, we need to understand the problems, the type of defects and the remedies. This post discusses common roof defects, their causes and the solutions.
Causes of roof problems
Improper maintenance results in failure to spot minor roof defects results in premature roof failure especially on built-up, low-sloped roofs.
Roofing materials degenerate on exposure to weather elements. Metal roofs experience rust due to rapid oxidation, while exposure to atmospheric pollutants accelerate the process of degradation.
Some developers use low-grade timber for roof framing and decks. These materials could result in roof failure owing to warping of the frame ends, subsequent shrinkage and failure by the joints to hold the supporting joists.
Some types of roofing materials are not fit for use in certain conditions. Shingle roofs are suitable for steep slopes, while low pitched roofing developments require materials with a continuous sheet over a wide area, such as tin.
Other causes include: Improper Application of Roofing Materials, Wind damage, improper storage, exposed nails, improper design and failure of flashings.
Types of Roof Defects and their remedies
Blistering is one of the most common roof problems. Blisters are long, thin areas that rise on the roof mainly due to the expansion of liquid or gas entrapment within the roofing system. We can prevent blisters by using drier materials, using insulated equipment and ensuring sound contact between roofing panels and other materials. Blisters are treated using asphalt coating and gravel. Larger blisters require removal of the entire raised portion and patching using alternating layers of asphalt and large felt.
Roof Shrinkage is the contraction of the membranes that overlays the roofing materials. The contraction may result from poor membrane design, poor application, use of wrong materials and venting. To avoid shrinkage, experts recommend proper installation. Remedies include replacement of affected sheets, pressure relief by cutting the flashing, securing of the field sheet and installation of new flashing.
Alligatoring is the cracking of the roof surface arising from exposure to excessive heat and UV rays. Oil drains out of a petroleum-based roof, leading to surface damage. Alligatoring is prevented by regular inspections and use of an anti-UV coating to prevent damage. Alligatoring is remedied by patching smaller areas and replacing roofing sheets in case of extensive damage.
Punctures are the most common and worrisome roofing problem, mainly caused by negligence of the personnel visiting the roof. Appearing as holes or tears, punctures could also occur as a result of debris being blown or tossed on the roof. A change in work behavior could help reduce punctures. Early detection and repair is a key remedy. Repair is accomplished by cleaning, priming and patching the membrane around the puncture.
Another major roofing problem is penetrations, which include: pitch pans, pockets and roof leaks. In the location of penetrations, such as chimneys, experts use a sealer to prevent further cracking. The sealant eventually grows weak due to vibrations and loss of plasticity. Improper installation may prevent the sealer from adhering to the penetration. Penetration errors are prevented by regular inspection and maintenance. Remedies include re-installation using epoxy and leakage evaluation.
Specific Types of Roof Problems
Some common problems with asphalt shingles include: curling due to moisture accumulation, raised shingles resulting from improper installation, premature cracking as a result of stress and movement, granule loss, thermal splitting & tearing, and blistering.
Pitched roof problems
Pitched roof designs experience such defects as roof spread due to the weight of interlocking tiles, nail rot due to moisture saturating the nail heads, moss buildup due to the stagnation of water on the rooftops, frost damage that causes tile breakage and cracked cement fillets due to sudden movements and moisture penetration.
Flat roof defects
Some defects associated with flat roofs include: ponding due to poor fall design, thermal movement as a result of solar-induced creasing, blistering, human interruption and poor workmanship.
Slate roof defects
While one of the best roofing alternatives, slate roofs have a few problems. They are susceptible to moss & lichen buildup, rust and fading. Slates are also significantly harder to install, difficult to maintain & repair and their heavy weight requires extensive support structures.
Single-Ply roof defects
Single ply roofs utilize a waterproof membrane reinforced with stone/roof pavers or mechanical fastening. Most common problems affecting single-ply roofing systems include: seam failure due to reduced elasticity, shrinkage, attachment failure and blisters.
Copper roofs are affected by acid corrosion due to acid run-off, deterioration due to condensations, staining arising from the metal’s weathering characteristics and mechanical damage.
This post has discussed the various causes of roofing defects, the types & remedies and the defects pointing to specific roofing types. These should serve as a guideline to identifying and solving most problems associated with roofing.
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