How do Ottawa contractors handle shower waterproofing in older homes with wood framing?

Ottawa has a substantial inventory of older homes — particularly in neighbourhoods like the Glebe, Sandy Hill, Old Ottawa South, Centretown, and Westboro — where wood-framed shower walls and plywood or plank subfloors present unique challenges for tile waterproofing. The good news is that experienced Ottawa tile installers deal with these conditions regularly and have well-established approaches to make modern waterproofing systems work beautifully in older construction.

The first step is always a thorough assessment of the existing framing and substrate. In pre-1970s Ottawa homes, it is not uncommon to find original bathroom walls framed with true-dimension lumber (actual 2x4s rather than modern 1.5-by-3.5-inch studs), lath and plaster behind old tile, and subfloors made of diagonal plank sheathing rather than plywood. Before any waterproofing goes on, the old tile, substrate, and any water-damaged framing must come out completely. This is where surprises happen — water damage behind old showers in Ottawa homes is extremely common, and it is not unusual to find rotted studs, subfloor damage, or even mould once the old tile and drywall are removed. Budget $500 to $2,000 for potential framing repairs in an older Ottawa home shower renovation.

Once the framing is exposed and any damaged wood is replaced, the walls get new cement board (Durock, Hardiebacker) or foam backer board (Kerdi-Board, GoBoard) screwed directly to the studs. In older homes where studs may not be perfectly plumb or evenly spaced, shimming the backer board to create a flat, plumb surface is critical — this extra prep work is one reason shower renovations in older homes cost more than in newer construction.

The waterproofing system then goes over the backer board just as it would in new construction — sheet membrane like Kerdi or liquid-applied membrane like RedGard or Hydroban, with all seams, corners, and penetrations properly sealed. The key difference in older homes is paying extra attention to the junction where the shower floor meets the walls and where the shower walls meet the ceiling or soffit. Older wood framing moves more than modern construction due to decades of seasonal expansion and contraction in Ottawa's climate, so flexible waterproof connections at these transitions are essential.

For the shower floor in older homes, the subfloor often needs significant work. Old diagonal plank subfloors must be overlaid with plywood to create a stable, flat substrate before the shower pan membrane or waterproofing system goes down. The drain connection in older Ottawa homes sometimes requires plumbing updates to meet current code — cast iron or galvanized drain pipes may need to be replaced with modern ABS. This plumbing work requires a permit from the City of Ottawa.

Expect a shower renovation in an older Ottawa home to cost 15 to 30 percent more than the same project in a newer home, primarily due to the demolition, framing repairs, and substrate preparation involved.

---

Looking for experienced contractors? The Ottawa Construction Network connects Ottawa homeowners with qualified professionals:

• Homeupgraders
• JC Carpentry
• Prism Services
• Extra Mile Tile Inc.
• M.O.T. CONSTRUCTION INC.