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Common Flat Roof Problems

There are many different types of flat roofing systems and they can all have problems if they are not installed, maintained and repaired properly. Alternatively with the many types of flat commercial roofs, you can avoid issues with quality preventative maintenance – this is an invaluable asset when it comes to having a long roof life.

Common Flat Roof Problems:

Deteriorating Flashing

Deteriorated Flashing
Flashing is used to prevent water from penetrating a junction. Problems can occur when it has been poorly installed or damaged and bent over time.

Empty Pitch Pockets

Empty Pitch Pockets
More than half of pitch pocket leaks are the result of someone sealing the pitch pocket with an improper sealant which leads to rust and and exposure to leaks.

Open Membrane Seams

Open Flat Roof Membrane Seams
In any roof system, regardless of material, improper workmanship in sealing seams is the most common reason for failure of new roof systems.


Ponding Water on a Flat Roof
This is one of the primary causes of flat roof leakages. Water will start to damage your roof’s material if it does not drain or evaporate within 72 hours.


Flat Roof Blistering
Even small amounts of trapped moisture can result in your flat roof membrane detaching from the layer below and cause roof "blisters".

Lack of Ventilation

Lack of Flat Roof Ventilation
A lack of ventilation causes condensation that can rot the roof decking and timber joists, and cause corrosion to any metal fixing components.

Moss or Silt

Moss on a Flat Roof
Vegetation and moss indicates water is being held in sufficient quantity to allow growth. This ultimately leads to warping, ponding and internal leakage.

Roof Rot

Rotting Flat Roof Deck
Condensation can rot the timber structure and cause unseen mold and spore build up that can cause a complete collapse of the roof and potential health issues.

Immediate problems that could come up:

  • Severe weather can mean severe and instant issues- High winds, hail, drenching rains that overflow the flashing height, lightning
  • Roof-top equipment installations - Improperly added equipment or other items improperly installed on the roof, a very common source of roofing problems are items added by tenants without permission or planning
  • Trade damage – membrane tears, holes, etc. caused by trades other than your roofing contractor when doing any work that requires roof access
  • Vandalism or accidental damage - even a small hole can let in a large amount of water into the roofing system

What can wear out your roof?

  • Structural movement – all buildings settle or expand/contract over time and depending on your roof type, it may not be very accommodating.
  • Exposure - either long-term exposure to the elements (sun, water, freeze-thaw) or shorter-term exposure to damaging air pollutants and chemicals which is not uncommon on commercial roofs
  • Plant growth - If proper care is not taken you could end up with a “green roof” unintentionally on a roof that was not built for it. Standing water or algae can hatch a garden.
  • Regularly delaying repairs – This can add up to a much shorter roof life. If a small problem is not repaired or it is delayed, this can result in a large amount of insulation being damaged.
  • Ignoring the importance of maintenance - This is perhaps the single biggest cause of premature roof failure, roof maintenance saves money.
  • Change in the use of the building – Perhaps you have a building that changes from a warehouse to homes. The change in relative humidity can cause an increase in the interior relative humidity of a building which can cause severe condensation problems within the roofing system.

At Roof Maintenance.ca we provide you with free consultation and detailed written estimates suited for your flat roof replacement and repair projects. We install durable and cost effective flat roofing systems backed with a leak-free warranty.

Click Here to Request a Free Estimate.

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Commercial Industrial RoofingRoof Scan.ca Acquired by Roof Maintenance.ca In a push to provide the Greater Toronto Area with the highest quality commercial and industrial flat roofing services available, Roof Maintenance.ca has acquired ownership of infrared flat roof inspection expert and industrial roofing contractor Roof Scan.ca. This unification of companies will create the most effective commercial and industrial roofing services the Greater Toronto Area [...] Read more

Contact Information

Roof Maintenance.ca
Toronto Flat Roofing Contractors specializing in flat roof repair, flat roof replacement and maintenance since 1999.
  • Mailing Address
  • 1630 Sismet Rd #1
  • Mississauga, ON. L4W 1R5