Subfloor Preparation

Subfloor leveling, moisture barriers, underlayment, and repairs

17 questions answered | Ask a free question

Our condo board requires specific underlayment thickness — how do we verify compliance before install?

Work directly with your contractor to obtain manufacturer specifications and have them provide written confirmation that the chosen underlayment meets...

6 views

Does self-leveler work on a cracked basement slab?

Self-leveling compound can work over a cracked basement slab, but the cracks must be properly prepared first. Simply pouring self-leveler over active...

9 views

Our hardwood feels slightly bouncy — does that mean subfloor issues?

Bouncy hardwood flooring usually indicates subfloor problems, though the severity can range from minor deflection to serious structural issues that ne...

13 views

The basement smells dusty after removing carpet — how should the slab be prepped before new flooring?

Dusty basement odors after carpet removal are common and indicate the concrete slab needs proper cleaning and preparation before any new flooring inst...

14 views

Our main floor slopes slightly — does that need structural correction before installing new hardwood?

Minor sloping in older Ottawa homes is common and doesn't always require structural work before hardwood installation. The key is determining whether...

18 views

Can I install flooring over old asbestos tile safely?

Installing flooring over intact asbestos tile can be done safely, but requires specific precautions and professional assessment. Never attempt to remo...

18 views

Our basement slab has hairline cracks — is that a problem for vinyl or laminate?

Hairline cracks in basement slabs are typically not a problem for vinyl or laminate flooring, as both are floating floor systems that can handle minor...

14 views

Our condo board says we need STC-rated underlayment before installing new floors — what does that actually mean and how much more does it usually cost?

STC-rated underlayment is acoustic insulation designed to reduce sound transmission between floors in condominiums. Your condo board is requiring this...

27 views

Our 1950s bungalow has original subfloor planks — is that stable enough for tile?

Original 1950s subfloor planks are typically not stable enough for tile installation without significant preparation. Most homes from that era have 1x...

26 views

What moisture reading is too high for hardwood install?

Moisture content above 12% in the subfloor or more than 4% difference between subfloor and hardwood is too high for installation. Most hardwood manufa...

37 views

The floors aren't level between rooms — can that be corrected before new install?

Yes, uneven floors between rooms can absolutely be corrected before your new flooring installation. This is actually a common issue in Ottawa homes, e...

50 views

Should sagging floor joists be corrected before any new flooring goes down?

Absolutely yes - sagging floor joists must be corrected before installing any new flooring. Installing flooring over sagging joists will cause prematu...

37 views

There's old adhesive residue stuck to the concrete — how is that removed properly?

Old adhesive residue on concrete requires mechanical removal and chemical stripping to create a proper surface for new flooring installation. The remo...

47 views

Our floor slopes toward one corner — is that normal settling or serious?

Floor slopes are rarely "normal settling" and usually indicate a structural issue that needs professional evaluation. While minor settling can occur i...

58 views

Can OSB subfloor cause problems with certain types of flooring?

OSB (oriented strand board) subfloor can cause significant problems with certain flooring types, particularly moisture-sensitive materials like hardwo...

43 views

Is self-leveling compound necessary for every flooring installation?

Self-leveling compound is not necessary for every flooring installation, but it's required when your subfloor has significant height variations that e...

38 views

How thick should the plywood subfloor be for hardwood installation?

For hardwood flooring installation, plywood subfloor thickness should be minimum 5/8" (15.9mm), with 3/4" (19mm) being the preferred standard for opti...

38 views
Get Free Estimate