Flat Roof Maintenance – Clogged Drains

The weather here in the Lower Mainland and Kamloops BC has been a whole mix of heavy rain, heavy snow, and well-below average freezing temperatures that have placed a burden on every roof

Large commercial and residential roofs have roof drainage systems that collect and quickly transport water away from the roof. Typically there will be multiple roof drains protected by a basket strainer to trap debris and prevent it from clogging the drainage pipe.

Accumulated water can add significant weight to a building. If the drains are clogged or poorly installed, the collected water cannot drain away fast enough creating a backlog of water that could overwhelm the roof’s weight capacity and could even lead to a catastrophic collapse

If the roof has frequent pooling or standing water, it could

  • Deterioate the roofing membranes and materials under the pooled water
  • Encourage plant, algae and fungus growth which could damage the roofing materials
  • Cause catastrophic collapse

Regular maintenance of the roof drainage system is essential to the life of the roof and ultimately the structure of the entire building. With a regular flow of rainwater, there will be a buildup of debris around the strainer which will eventually clog the strainer and prevent water from draining away. If the wet debris is not frequently removed it will degrade the seams and sealants around the drain

However, in the last couple of weeks in Vancouver, the Fraser Valley, and Kamloops we have been busy with a different kind of flat roof drain maintenance – removing ice from drains that were completely iced over


As you can see, these huge spun copper drains are completely iced over. There is nowhere for the melting ice and snow to go. As a result, water ingress can happen through certain types of roof vents and other protrusions on the roof deck.

We, therefore, opened up the drains and made paths for the water to flow. We also added a little bit of a salt-type solution (safe for the roof) to ensure that these pathways stay open, so that the water can be completely drained off the roof.


This is just another example of how important roof maintenance is to the longevity of your roof and the house below it. If you have any concerns about ice buildup on your roof, ice dams or any other roofing needs, please feel free to reach out to us by phone or email!