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Balcony Repair & Waterproofing

Slope Reversal

Our specialized materials that allow thin patch applications​ make it possible to reverse inverted or flat balcony slope.

Concrete Slab Restoration

We do extensive patching which allows us to restore balcony flooring instead of recasting the slabs*.

Permanent Waterproofing

Our specialized industrial-strength materials have been rated to the MTO standards to last 25 years.

* Slab recasting is done if specified by structural engineers.


Cost Savings

Since we can do extensive patching, condo balcony flooring and other balcony surfaces can be restored instead having to be recast*.

Flood Damage Prevention

A flat or inverted balcony slope is one of the reasons a unit can be affected by water damage. Our application methods allow us to correct this issue.

Decorative Protective Finish

Protective coating is followed by a layer of specialized ​UV-resistant non-slip paint, which protects the surface against weather elements and makes it safe to walk on.

* Slab recasting is done if specified by structural engineers.

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About Us

Joint Seal Waterproofing is a company based in Toronto, specializing in balcony repair and waterproofing. Our services cover a vast geographical area, from Hamilton to Mississauga, the City of Toronto, and the surrounding GTA communities.

We fully repair condo balcony and terrace flooring, restoring their load-carrying capacity. Balcony slab geometry is completely restored with thin patch applications.

Typical scope of balcony repair and waterproofing consists of surface patches, crack repairs, and a decorative, UV-resistant, waterproofing finish. In some cases, the slope of the balcony floor needs to be reversed to drain the water away from the unit wall.

Repair Methods

Balcony Slope Reversal

In some cases, balcony slope is either flat or inverted towards the unit. Balcony slope reversal is not possible with traditional repair methods, as they cannot produce thin patch application where patch thickness varies between 0.25 and 0.01 inches (traditionally, patching requires a minimum of two-inch demolition in the affected area).

The use of specialized concrete adhesives and polymer cement permits thin patch applications, making the job much more cost-effective and faster.


All loose unsound concrete is removed, and concrete surfaces are cleaned in preparation for patching and restoration of balcony slab geometry.

Under traditional repair methods, large parts of the balcony slab would require complete demolition and recasting. The use of specialized concrete adhesives and polymer cement permits thin patch applications, making the job much more cost-effective and faster.

Balcony Crack Repair

Crack repair is the most cost-effective way to waterproof a balcony and prevent future extensive repairs.

Traditionally speaking, two slabs of concrete cannot be fused together when there is a crack. Our specialized materials make monolithic 1.85 MPa adhesion possible, which allows for complete concrete repair and restoration. It works both on single-defined and multiple cracks.

Decorative Protective Finish

After the balcony slab is fully repaired, protective coating is applied to ensure long-lasting balcony waterproofing. It is followed by a final layer of specialized UV-resistant, non-slip paint with a nice decorative finish.


For more information,

Q: Water is leaking inside my apartment from my balcony – how can that be fixed?

This occurs when the normal balcony slope (towards the street) is flat or inverted. Because our specialized materials allow for thin patch applications, we can reverse the balcony slope, avoiding leaking caused by this problem.

Q: Pieces of my balcony floor have fallen off – will the entire floor have to be redone?

Under traditional methods it would have to be – new concrete does not adhere to existing surfaces. However, by using our industrial-strength adhesive, we are able to perform extensive patching, fully restoring balcony surfaces.

Q: Can balcony cracks be fixed?

Traditionally no, because old and new concrete cannot be fused together. Our industrial-strength adhesive does make it possible.

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