Although a commercial membrane roof can have a lifespan measured in decades, eventually the time will come when replacement is necessary. The following can help you understand the basic replacement process.
Every roof replacement begins with a professional inspection and assessment. Your roofer is looking for anything that could complicate a basic replacement, such as existing damage from leaks that must be repaired, the state of the insulation and roof decking beneath the membrane, and whether an older roof needs any safety upgrades, such as reinforced supports. Assessment is often completed before the final work estimate is provided.
2. Tear Down
Tear down for a membrane roof means removal of the old membrane along with other components such as flashing and vent seals. It may also include the removal of damaged decking in preparation for replacement, along with pulling out old mildewed or wet insulation from areas where roof damage allowed for a leak. In many cases, the roof is torn down to its bones so all parts can be replaced.
Insulation makes up the first layer of a flat commercial roof. Unlike a pitched roof where insulation is installed via the attic, flat roof insulation is installed over the roof supports but under the decking, working from the top down during a roof replacement. The type of insulation can vary, but often a combination of batt or panel installation along with spray foam insulation is used to ensure there are no gaps in coverage.
4. Membrane Installation
The next step is laying down the membrane. This begins with repairing or replacing any damaged areas of the decking. Then, a membrane, often made of EPDM for modern commercial roofs, is installed and anchored over the decking. The key to successful membrane installation is laying it in a way to minimize seams to ensure there are no wrinkles or poorly anchored areas.
5. Weather Sealing
The final step is sealing against moisture. Seams are all sealed, along with the perimeter of the membrane. Flashing and seals are also installed around rooftop protrusions and appliances, such as vent stacks and HVAC units. In some cases, your roofer may also apply a roof coating in order to more fully seal the roof against moisture and weather damage. This coating can help extend the life of your new roof.
Contact a commercial roof replacement contractor for more information about the process.