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Flat Roof
Repairs & Waterproofing

Spray-On Applications

A seamless fast-curing waterproofing membrane ensures complete
durable flat roof repair.

Time-Efficient Repair

Spray-on applications are much faster than roll-on methods.

Greater Temperature Application Range

Our material can be applied at temperatures as low as -5°C –
an advantage in commercial roofing industry.


Cost Savings

Shorter application time and material durability ensure savings.

Easily Adaptable

Application thickness can be easily adjusted, as required.

UV Protection

Light-colour surface helps reduce heat absorption. A UV-protective layer is applied for more durability.

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About Us

Joint Seal Waterproofing is a Toronto-based company, specializing in commercial roof repair and waterproofing. We provide flat roof repairs in a vast geographical area, from Hamilton to the City of Toronto, including Mississauga and all of GTA.

Fixing a flat roof may require crack repair and patching ahead of roof membrane application. Each flat roof membrane installation and design is specified by an engineering consultant.

Throughout our portfolio of flat roof membrane installations and waterproofing, we have had experience with most of the typical membrane types.

Repair Methods

Crack Repair

Thanks to monolithic adhesion provided by our products, flat roof repairs are done quickly and efficiently.

To repair a crack on any concrete surface, a clearly defined procedure is followed. Cracks are prepped and then treated with specialized, industrial-strength adhesive, after which they are filled with polymer cement and a waterproofing primer.


Under traditional repair methods, patching concrete requires a minimum of two-inch demolition in the affected area.

The use of specialized, industrial-strength materials permits patches as thin as 5 mm on any surface, making flat roof repairs much more cost-effective and faster.

Fixing Debonded EPDM Membrane

A five-layer coating is applied after the roof surface is flattened, to provide an optimal commercial roof repair.

To fix a debonded EPDM membrane, the following procedure is applied:

  1. The surface is power washed, and valleys are fixed with a self-leveling material.
  2. A fire-rated protector board is installed.
  3. Heavy sheets are then placed to flatten the roof, and the joints between them are detailed.
  4. Finally, a five-layer coating is applied: specialized PU-100 primer, PU-500 liquid waterproof membrane, fleece material, another layer of PU-500, followed by UV-resistant coating.

Repairing Delaminated Corners and Edges

Leaking around the delaminated edges is prevented.

Flat roof leaking around the delaminated edges is corrected by using Butyl tape and detailing them with PU-500 liquid waterproof membrane.


For more information,

Q: My flat roof is leaking – does it have to be replaced?

A: No, unless the damage is extensive, and the existing materials no longer provide adequate protection.

Q: Can a flat roof be repaired?

A: It depends on roof age, type of damage and existing materials.

Q: How long does it take to repair a roof?

A: It depends on roof size and the extent of damage. Our new spray-on Green Skin application is significantly faster than traditional methods and provides much more durable results.

About Us

Joint Seal Waterproofing, Inc.

Our Contacts

25 Coronet Rd, Unit 8
Etobicoke, Ontario, M8Z 2L8

Phone: (647) 479-4069
US/Canada Toll Free: 1-855-561-4416