How to Prepare Your Subfloor for a Perfect Flooring Installation

One of the most overlooked steps in any flooring project is subfloor preparation. No matter how premium your chosen flooring is, a poorly prepared subfloor will cause creaking, lifting, and premature wear. Here's everything you need to know.

Why Subfloor Prep Matters

Flooring manufacturers typically require the subfloor to be flat within 3mm over a 1.8m span. Variations beyond this can cause:

• Hollow spots and bouncing underfoot
• Joints opening over time
• Clicking or creaking noises
• Voided warranties

Step 1: Check for Moisture

Moisture is the enemy of most flooring types. Before installation, conduct a moisture test using a calcium chloride test or a moisture metre. For concrete slabs, readings should be below 75% relative humidity.

Tip: If moisture levels are high, apply a moisture barrier or use a self-levelling compound with moisture suppression properties.

Step 2: Level the Subfloor

Use a long straightedge to identify high and low spots. High spots can be ground down, while low spots should be filled with a quality self-levelling compound. Allow it to cure fully before proceeding.

Step 3: Remove Old Adhesive and Debris

Scrape off any old adhesive, glue, or paint. Vacuum thoroughly. Even small debris can telegraph through your new floor.

Step 4: Check for Squeaks (Timber Subfloors)

For timber subfloors, walk across the surface and mark any squeaky spots. Screw these areas down with appropriate flooring screws to eliminate movement.

Step 5: Acclimate Your Flooring

Bring your flooring into the room 48 hours before installation to allow it to acclimatise to the room's temperature and humidity. This is especially important for timber and hybrid products.

Ready to Install?

Once your subfloor is clean, flat, and dry — you're ready for installation. Need a professional? Find a TradePlus installer in your area today.