The first thing you want to do is check each room in the building thoroughly. Look at the ceiling for any discoloration. If there is a leak, a dark colored ring will usually form around the saturated area. If you see this, you will want to call a roofing contractor before proceeding. Just because you see damage from a leak in a specific area doesn’t mean the leak is located directly above. Flat roofs have layers that may direct the water to another area in the building, often many feet away. The damage could also be from a plumbing leak or another source other than your roof. It is also possible the leak causing the stain was already fixed, and the ceiling was not. To be safe, it is best to hire a roofing contractor to locate the leak.
If you do not see any discoloration or other obvious signs of a leak, it is still a good idea to inspect your roof. Cracks could be forming that could soon become problems. It is better to deal with these before they cause any internal damage to the building. It is a good idea to walk your roof and do a simple inspection. Be sure to always remain aware of where you are on the roof and never walk backwards. Be aware of penetrations and don’t put any weight on skylight covers as they are not designed to hold your weight. While walking, pay attention to how the roof feels underneath you. If it is weak, immediately get off the roof in a safe manner and call a contractor. If there is a leak, it may soak the insulation underneath the membrane. If you sense a sponge-like feel to the roof beneath you, you want to contact a roofing contractor. This is also true if you see water coming out of any area of the membrane.
Next, you will want to check penetrations and seals. A large portion of leaks are at penetrations and seals, which make up a small percentage of the total roof. Penetrations are areas such as pipes and flashings that ‘penetrate’ the roof. They are usually surrounded by flashings, or sheet metal. Check around these penetrations for any cracks. These cracks may not initially be a problem, but as water gets in and freezes, the ice will expand the crack until it is deep enough to cause a leak. Seals are where two waterproof materials overlap or come together. Check these to be sure they are smooth and fully adhered.
Other serious flat roof issues include:
- Blisters: these are areas that appear as bubbles or as an uneven surface. They could be moisture trapped under the membrane, but are more often a result of an installation error. Ask a roofing contractor if a particular blister on your roof will cause problems.
- Splits: These are often indicators of poor building structure or poor insulation installation. Even if the membrane was installed correctly, shifting or movement inside the structure could have caused a split in the membrane. If this is the case, the flashing in this area will usually fail as well.
- Movement: If the membrane seems to have moved from it’s original location, it may be due to the slope being too steep for the membrane installed, inadequate adhesion, or thermal problems. This can contribute to ridges, splits and other roof problems.
- Damage: Obviously, if your roof is punctured or shows any signs of damage, report it to a roofing contractor.
- Shrinkage: Some membranes have a tendency to shrink excessively. You will see this as an issue if membrane seams to be pulling against a penetration such as a plumbing vent pipe, or the membrane can pull away from the eave’s edges. You may also see “bridging” at angle changes such as parapet walls against other walls etc.
If you have completed your roof inspection and have decided to hire a roofing contractor, be sure to get multiple bids to be sure you know what really needs to be done. Also, if you get multiple bids, you are more likely to pay a fair price for your roof repair or replacement. Your contractor may also be able to help you prolong your roof and give specific instruction on what you can do to properly maintain it.