Flat Roofs · Toronto & GTA
Flat Roof Repair & Waterproofing
Joint Seal specialises in seamless, fast-curing, polyurea-based spray-on membrane applications that ensure complete, durable waterproofing. Our material can be applied at temperatures as low as -5°C.
- Polyurea Membranes
- Spray-On Waterproofing
- Crack Repair
- Patching
- Roof Capping
- Metal Roofs
Flat Roof Repair & Waterproofing
We offer durable polyurea-based waterproofing solutions for concrete and metal (including corrugated metal) flat roofs.
Our cold-applied membranes — both roll-on and spray-on — provide lasting results for projects of any scale. Crack repair and patching are done ahead of membrane application, as needed.
Why Flat Roofs Leak
Bituminous roofs age with time due to weather-related wear-and-tear, becoming brittle and cracking after exposure to the sun and going through freeze-thaw cycles. When water infiltrates through such cracks, the roof begins leaking.
Other reasons for leaking could be gaps created by shifted aluminum capping or penetrations, such as a pipe going through a roof. With time, the seal dries out from exposure to the elements and regular contraction and expansion.
Our Solutions
Cold-Applied Polyurea — our polyurea-based membranes can be rolled on or sprayed on, depending on project size and other characteristics.
Crack Repair, Patching & Roof Capping — if a concrete roof has cracks or delaminated concrete, we fill and patch before the membrane is applied. We also realign shifted aluminum capping, seal any gaps and apply a top coat for lasting results.
Our Repair Methods
Flat Roof Waterproofing
From crack repair and thin-patch concrete restoration to seamless polyurea membranes on concrete and metal — these are the core methods we use to waterproof large roofs quickly.
Crack Repair
Thanks to the 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 specialised, industrial-strength adhesive, after which they are filled with polymer cement and a waterproofing primer.
Patching
Under traditional repair methods, patching concrete requires a minimum of two-inch demolition in the affected area.
The use of specialised, industrial-strength materials permits patches as thin as 5 mm on any surface, making flat roof repairs much more cost-effective and faster.
Polyurea-Based Membranes
We waterproof concrete, metal and corrugated metal roofs.
Concrete Roof Repair — after gravel, rigid insulation and fleece are removed, the concrete surface is cleaned. Cracks and patching are done as needed and primer is applied. A polyurea-based membrane is then sprayed or rolled on, as required by the project, followed by a polyurea top coat.
Metal Roof — before applying primer, we ensure the roof surface has no oil, rust or debris. Metal is cleaned with a sand blaster or grinder, followed by a solvent to remove any oil. Primer is applied, followed by polyurea.
Common questions
Frequently asked questions
My flat roof is leaking — does it have to be replaced?
Not usually. Full replacement is only needed when damage is extensive and the existing materials no longer protect the structure.
Can a flat roof be repaired instead of replaced?
In most cases yes — it depends on the roof's age, the damage, and existing materials.
How long does a flat roof repair take?
It depends on size and damage. Our spray-on polyurea membrane is far faster than traditional methods and more durable.
Leaking flat roof?
We repair cracks, patch concrete and apply seamless polyurea membranes on concrete and metal roofs — fast-curing, cold-applied and built to last.