Can I pour a thin concrete topping over an uneven wooden subfloor for tile installation in my Rothesay home?

No, you should never pour concrete directly over a wooden subfloor. Concrete and wood move differently with New Brunswick's seasonal humidity changes, and the concrete will crack and fail within months of installation.

For tile installation over an uneven wooden subfloor in your Rothesay home, you have several proper options that will create a stable, long-lasting foundation. Self-leveling compound is the most common solution for minor irregularities (up to 1/2 inch over 10 feet). This polymer-modified compound bonds to wood and flexes slightly with seasonal movement, unlike rigid concrete. Expect to pay $2-4 per square foot for professional application.

For more significant unevenness, plywood overlay is the gold standard. Installing 1/2-inch or 5/8-inch exterior-grade plywood over your existing subfloor creates a perfectly flat, stable surface for tile. The plywood moves as one unit with your wooden subfloor, eliminating the differential movement that causes concrete toppings to crack. This approach costs $1.50-3.00 per square foot for materials plus labor, but provides the most reliable long-term performance.

Cement backer board (like Hardiebacker or Durock) installed over your leveled subfloor is essential for any tile installation. This provides the rigid, moisture-resistant substrate that tile requires. The sequence should be: wooden subfloor → leveling (if needed) → cement board → tile. Never skip the cement board step, even if your subfloor appears flat and solid.

Given Rothesay's proximity to the Kennebecasis River, your home likely experiences typical Maritime humidity swings that make proper substrate preparation even more critical. Spring moisture from snowmelt and summer humidity can affect wooden subfloors, so ensure your subfloor moisture content is below 12% before any overlay work begins.

When to hire a professional: Subfloor assessment and preparation accounts for 40-50% of a successful tile installation. An experienced installer can determine whether your subfloor needs additional support, identify squeaks or loose areas that must be addressed, and ensure proper deflection limits for tile. For bathrooms and kitchens where moisture resistance is critical, professional installation of the cement board substrate with proper seaming and waterproofing is worth the investment.

Get quotes from local tile installers who can assess your specific subfloor conditions and recommend the best leveling approach for your Rothesay project.