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Inspecting Your Flat Roof

While we always recommend yearly roof inspections by an expert, there is a lot of time between each one and a lot can happen from storms to improper servicing.

If you have reason to be worried, or you just want to keep on top of such an important asset, here are a few things that you can check on your own.

General Inspection

First thing to do is take a look around for anything obvious. Is there standing water, scrapes or scuffs in the membrane that wasn’t noted on your last inspection, tree limbs or other debris from a recent storm?

Walk around the whole roof looking at the state of the membrane, especially if you’ve had people working on your roof recently, pay special attention to anywhere they might have walked or carried equipment.

If you have had people working and they used a welder or any other source of heat, it’s a good idea to look specifically for burn marks or areas of melted membrane. We often find that other contractors, not understanding the nature of flat roofs, do significant damage to the roof without realizing or reporting the problem.

Drains, Drains, Drains!

Cleaning drains is the most important thing that a roof owner can do for a flat roof!

When drains get clogged, water sits on the roof for longer and has more time to seep into cracks and crevices. Certain membranes deteriorate faster when there is standing water and the extra weight of the water can cause certain flat roofs to sag and exacerbate the problem.

According to the National Roofing Contractors Association, water should not remain on a flat roof for more than 48 hours after a rain. This should happen naturally if your roof is leveled and the drainage is working properly, but if drains are clogged or if part of the roof has sagged then the water may not clear in this time.

If you are worried that your roof isn’t clearing in time, take a look at it a day after a significant rain. If there is ponding, try to determine the cause. Clear any debris from drains, but if this doesn’t work, or if you notice that the drain is higher than the water level then your roof might have sagged around the drain.

In this case you will need to call your roofing contractor to come and solve the problem. This may include filling the low spots around the existing drain, adding a new drain at the lowest point, or lowering the existing drain.

Perimeter Inspection

Walk the perimeter of the roof looking for places where the flashing has become loose or is no longer covering the top of the membrane. In corners look for cracks or areas where the membrane is pulling away from the building.

Some types of flashing rely on caulking to keep water out. Inspecting the caulking for damage or age, particularly around brick or cinder block walls, is a great way to prevent leaks from developing. As the perimeter is where many leaks occur, this is an area where details are important.


Check all penetrations (things that go through the roof) to make sure they are properly sealed. If there are pipes or wires coming through the building make sure that they have been sealed on all sides. This is especially important if you have had work done on your roof since your last professional inspection.

Many times we have seen penetrations which have only been sealed on the top but are under the water level during a heavy storm! Again, it is always best to have your flat roofer inspect any new work to ensure that it hasn’t affected the performance of the roof, but if that’s not possible then you, at least, should go and inspect any work in close detail and with a watertight roof in mind.

Flag Areas of Concern

If there are things you notice that concern you, flag them with pylons, rocks, or any visible marking so they are easily found later. If you have serious concerns and plan on calling your roofer this will save him time and you money as he is able to find the area quickly.

If you are unsure whether your roofer needs to do a site visit you can always take a picture or video and email him asking his advice.

Do Not Attempt Repairs

One of the biggest mistakes that we see often is building owners or other contractors attempting to fix problems themselves without a firm grasp of flat roofing practices and products.

Before attempting a roof repair be sure to call your flat roofing contractor, even if only for advice. He will be able to tell you the best solution and the appropriate product to use.

Many regular sealants purchased at retail stores are not well suited to roofing applications, and will break down or fail quickly. Your roofer will know what to use and what will aggravate the situation.

Repairs improperly done, either by building owners or other contractors, often lead to more expensive repairs later. Make sure that the repair you discuss with your roofer is going to help, not hurt the situation.

Contact Northern Seal today to schedule your yearly inspection, or to discuss concerns you found during your latest DIY roof inspection.