Can I refinish a hardwood floor that has deep pet urine stains or does the wood need to be replaced in NB?

Deep pet urine stains can often be successfully removed during professional hardwood refinishing, but the success depends on how deeply the urine has penetrated into the wood and subfloor. In New Brunswick's humid Maritime climate, urine damage tends to penetrate deeper and linger longer than in drier regions, making assessment and proper treatment even more critical.

Surface-level staining that hasn't penetrated through the wood's finish can usually be sanded out during a standard refinishing process. The drum sander removes the damaged surface layer along with the old polyurethane, revealing fresh wood underneath. However, deep stains that have soaked through to the subfloor require more aggressive treatment and may need board replacement in severely damaged areas.

Professional assessment is essential because urine damage isn't always visible from the surface. A flooring contractor will check for soft spots, black staining that extends through the full thickness of the board, and persistent odour even after surface cleaning. They'll also inspect the subfloor underneath for damage, as urine can seep through gaps between boards and compromise the structural integrity of plywood or OSB subflooring.

In New Brunswick's climate, moisture from pet accidents gets trapped longer due to our high humidity levels, especially during summer months when indoor humidity can exceed 60%. This extended moisture exposure allows urine to penetrate deeper into the wood grain and can lead to mould growth in the subfloor. The ammonia in urine also reacts with tannins in certain wood species like oak, creating permanent black staining that may not sand out completely.

Treatment options depend on damage severity. For moderate staining, contractors may use specialized wood bleaching products after sanding to neutralize remaining discoloration. Severe damage requires board replacement — individual boards can be cut out and replaced with matching wood, then the entire floor refinished to blend the repair. If subfloor damage is extensive, that section may need replacement before installing new hardwood.

Odour elimination is crucial and often the most challenging aspect. Even after sanding and refinishing, odour can persist if urine has reached the subfloor. Professional treatment may include sealing the subfloor with odour-blocking primer before refinishing, or in extreme cases, replacing contaminated subfloor sections.

Cost considerations for refinishing with pet damage treatment typically run $4-$7 per square foot in NB, compared to $3-$5 for standard refinishing. Board replacement adds $8-$15 per square foot for the affected areas. If more than 20-30% of boards need replacement, installing new flooring may be more cost-effective.

Hire a professional for this work — pet urine damage assessment requires experience to determine what can be saved versus what needs replacement. The specialized sanding, bleaching, and sealing techniques needed for odour elimination are beyond typical DIY capabilities, and mistakes can make the problem worse or create permanent damage to salvageable wood.