Structural standing seam metal roofs for flat buildings are practical, reliable and long-lasting. However, time eventually catches up with metal, and rusted roof decks and leaks may start to compromise the building’s integrity.
Here are some of the most common problems that lead to leaks and larger repair and maintenance budgets:
- Loose seams and cracked penetrations. Roofs expand and contract with the weather. Because metal roofs are made of rigid sheets fastened together, this expanding and contracting loosens screws, pulls at seams, and causes cracks to form around stacks and other penetrations.
- Rust and corrosion. Moisture’s effect on steel is well known. Snow, rainfall, and ponding water eventually cause rust and corrosion to form and holes to appear.
- Interior Drips. Cold temperatures chill inadequately insulated metal, causing warmer moisture vapor inside the building to collect as water or frost on the underside of steel roofing panels. This condensation effect can cause dripping inside, even when the weather is dry outside. And the problem is compounded when oxidation occurs and rust forms on the inside of the building.
- Ice build-up. Ice build-up in gutters can block water from properly draining off the roof during a thaw, creating a drainage back-up and providing more opportunities for moisture to enter through a metal roof’s seams.
There are several solutions to the problems caused by aging metal roofs:
- Sealing and coating. This inexpensive option re-seals exposed seams and applies a waterproof coating. But this method only protects against rain and only temporarily, because the roof continues to expand and contract, eventually rupturing the new seals and the coating.
- Spray-on foam and sealant. This covers the metal roof with urethane foam which is then sealed. Although this method helps protect against rain and interior drips, the irregular surfaces of foam coatings typically collect water, and most warranties for spray-on foam do not cover damages due to ponding water.
- Roof replacement. Completely replacing the roof with new insulation and new steel addresses all the problems – until they begin again, because the new metal roof will have the same vulnerabilities as the old roof. This method is also costly, involves the use of heavy equipment, and is disruptive to normal operations, often exposing building contents to the elements while work is performed.
- A great alternative to these options is a single-ply membrane metal retrofit system. It is installed right over the existing roof deck, and includes additional layers of insulation to improve energy efficiency and provide a smooth surface for installation. A single-ply retrofit can protect your building against rain, temperature changes, interior drips, ice build-up, as well as rust and corrosion. It can be installed at a fraction of the cost of a replacement metal roof (without disrupting building operations), and is a better long-term solution than sealants, coatings and foam.