Why Toronto tile installation needs a stiff, flat base
Ceramic and porcelain tile crack when the floor under them bends. The TCNA sets L/360 as the deflection limit for ceramic and porcelain over wood framing, and L/720 for natural stone. In older Toronto houses we check joist span and subfloor thickness, add plywood where needed, then install an uncoupling membrane. Tile is set in thinset with the coverage ANSI A108 calls for (at least 80% contact in dry areas and 95% in wet areas), and large-format tile gets a levelling system to control lippage at the edges.

