Terrace Renovation
Casa Loma, Toronto.

About This Project

A terrace above a garage is one of the more technically demanding waterproofing scenarios we take on. The structure is fully exposed to the elements, takes the full load of freeze-thaw cycling every winter, and when it fails, the water goes directly into the space below. This Casa Loma terrace had been leaking into the garage. The existing surface was removed entirely, the structure was assessed, and we started fresh with a proper system rather than patching over the existing one.

Patching a failed waterproofing assembly on a structure like this is almost always a temporary fix. The membrane underneath has already been compromised and any repair that does not address the full deck is going to fail again at a different point within a few seasons. The only way to get a 10-year warranty behind it is to do it properly from the start, which is what we did here.

The tile specification matters more on an exterior application than almost anywhere else. We used 20mm thick outdoor porcelain pavers, which is the format specifically engineered for this kind of use. At twice the thickness of standard tile, it handles frost, load, and thermal movement without cracking. It does not need sealing, it does not stain, and it looks the same in year ten as it did when it was installed.

Slope-to-drain was set correctly across the entire deck surface before any tile went in. This is the part of a terrace renovation that is invisible once it is done, but it is what determines whether water sheds off cleanly or ponds and tests the waterproofing membrane underneath. Getting it right at this stage is non-negotiable.

The client received a written 10-year warranty against water leakage into the garage below. The terrace is now a properly functioning outdoor space that will hold up through the Toronto winter for years to come.