When a low-slope structural metal roof (commonly used on commercial buildings) becomes deteriorated, the best option might not be tear off and replacement.
While metal roofs are known for being durable, lasting for fifty years or more, they are still susceptible to the elements. Extreme temperatures cause them to expand and contract, over time causing the seams to become loose. On structural metal roofs with poor drainage, standing water can cause rusting. These problems will eventually undermine the durability of the roof, requiring it to be repaired or replaced.
Replacing a metal roof with a new one is costly and interrupts business operations, and the new roof will eventually suffer the same problems as the previous one. A better option is installing a single-ply roofing system right over the metal roof because it is a cost-effective, quality alternative that makes replacement unnecessary. These metal retrofit systems are installed over damaged, commercial metal roofs and provide long-term protection.
Installing single-ply membranes on top of a metal roof is simple. First, strips of insulation are cut to fit neatly in the metal deck flutes (the space between the ribs) creating a smooth, flat surface. Then, another layer of insulation is positioned over the entire roof, which gives the roof an added R-value and provides a solid surface for the membrane. The single-ply, prefabricated membrane is then rolled over the insulation and mechanically fastened to purlins or the metal deck itself.
Advantages of the metal retrofit system:
- No leaks, rust or corrosion
- No metal seam or loose fastener problems
- Thermoplastic membrane expands and contracts with temperature extremes
- Membrane reflectivity helps provide energy savings
- Installation does not affect normal business operations
- An easy, long-term solution
Other repair options do exist, but these solutions will only temporarily solve the problems. Resealing the exposed seams and applying a waterproof coating is the cheapest option, but eventually the seals will break. Another solution is using spray foam, but a foam surface is typically uneven and collects water, and doesn’t provide long-term durability.