What did the snow hide? 10 Spring Flat Roof Inspection items

Performing annual inspections and maintenance for your flat roof will ensure it functions correctly and lasts its intended service life.

Roofing is one of the largest capital replacements a building faces, yet it is often neglected and ignored unless someone reports a leak. Yet just because the roof isn’t leaking, that doesn’t mean it does not require maintenance and repairs. Sunscreen is applied before, not after, the burn.

This spring, check your flat roof for the following:

1. Open seams and laps

Many cold and torch-applied roof systems are installed in a rolled format, such as 2-ply modified bitumen, TPO, and EDPM. The laps in the membrane are the natural weak spots in the roof system and bear the brunt of from freeze-thaw cycles experienced in Canada. It is important to check the seams to ensure they still fully adhere to the adjacent roll of membrane. Any membrane that is debonded should be repaired and resealed.

2. Organic Growth

While green roofs are all the rage these days, inadvertent green roofs are damaging to roof membranes and lead to premature failure. Organic growth, such as moss, saplings, and weeds commonly occur around the perimeter of a roof and at roof drains. This organic growth should be removed from the roof and any residue should be cleaned off.

3. Low Spots

As your building shifts and ages, slight adjustments may occur to the sloping of the roof. If the sloping of the roof is modified through natural movement, ponding water can occur. Ponding water can prematurely degranulate modified bitumen membranes and unnecessarily expose the membrane to harmful UV rays drastically reducing its service life. Additionally, leaks occurring where ponding water is present cause additional water infiltration and are difficult to repair.

4. Sealant Failure

Sealant is often portrayed as a magical product that keeps the water out of our buildings. However, sealants will harden and lose their elasticity as they age, causing them to crack and delaminate from surfaces, potentially leading to water infiltration. Therefore, sealants should be replaced when they are dry, cracked, hard, or delaminated. Any existing sealant must be completely removed prior to new installations as many sealants do not adhere well to one another. Furthermore, selecting the proper sealant for the application is important, as sealants are not 'one-goop-fits-all'.

5. Drains

Flat roofs typically are internally drained, meaning they have a roof drain that catches the water and expels it through a piping hidden inside the walls of the building. Drains have numerous parts all of which require review and maintenance. Clamping ring bolts should be tight so that the ring makes positive contact with the membrane. The drain cage should be installed and attached to the clamping ring to ensure that no foreign debris or objects get inside the piping. Lastly, all debris, including organic growth, must be regularly removed to allow water to flow freely into the drain preventing prolonged periods of ponding water.

6. Nests and animals

While you make yourself comfy and cozy inside your building, animals are doing the same on your roof. Birds love building nests on top of various roof top penetrations, or under the protection of a penthouse. Animals living on your roof will throw random debris that they have collected on it, potentially clogging the drains. Even worse, animal droppings contain ammonia damaging to roof membranes. Nests should be removed from the roof as soon as possible. Additionally, animal control measures, like bird netting or wall spikes, can be installed on your roof to make sure animals don’t get any bright ideas about returning. Those stubborn birds sometimes require more drastic measures.

7. Metal Flashings

Flashings are typically capping the parapet and protect curbs on the roof. Ensuring that they are adequately secured and do not move, bend, or shake in the wind is important. Loose flashings can be a safety concern, as they could dislodge and hit nearby people or buildings. Loose flashings may also allow water penetration into the roof system and the building. Often loose flashings can be simply secured with new fasteners.

8. Penetrations

Your flat roof contains many penetrations, including plumbing stacks, roof anchors, chimneys, or curbs for mechanical equipment. All of these penetrations contain a unique set of challenges when keeping your roof watertight. Each penetration should be carefully reviewed and any repairs should be unique to the penetration. Many penetrations rely on sealant or flashing to ensure water tightness, both of which may require replacing before the entire roof does.

9. Transitional walls

Transitions are found when there are multiple roof levels, or when there is a penthouse on the roof. These types of transitions typically involve multiple trades and building components coming together. Special care should be given to these details to make sure none of the waterproofing components are delaminating or failing. Leaks at transitions are among the most expensive and difficult to repair, so merit diligent attention.

10. Parapets

Parapets are one of the most common points of failure on a roof and should be treated with special care. Parapet membranes have the tendency to delaminate from the substrate. When the membrane delaminates, the seams in the membrane tend to split open under stress and allow water infiltration.

Whether your condominium is protected by a flat roof or a sloped one, having a trusted industry professional perform these reviews is important. In addition, a similar checklist should be performed in the fall before the first snowfall as well. Nothing is worse than trying to trace a leak when your roof is covered by two feet of snow. Just because you cannot see the problems brewing, or nothing is leaking, doesn’t mean something isn’t happening to your roof. At Keller Engineering, our team of professionals is happy to assist you with any of your roof maintenance needs or roof problems.