Subfloor Preparation: The Ultimate Guide to Flawless Flooring Installations for Professionals

Before you can enjoy the aesthetic and functional benefits of new flooring, there’s one essential step that should never be overlooked: subfloor preparation. Whether you're installing laminate flooring, hardwood flooring, vinyl flooring or tiles, the flooring is only as good as what lies beneath it.

In this guide, we’ll walk you through the complete process of preparing your subfloor for a flawless installation. Perfect for builders and flooring professionals alike, this article helps ensure a stable, level and long-lasting result every time.

Why Subfloor Preparation Matters

Cutting corners during subflooring preparation isn’t just a quality issue; it affects your profits - think warped boards, squeaky steps & uneven finishes, which lead to unbillable fixes and unhappy customers. Proper prep creates the foundation for stability, durability and professional-looking results, protecting your reputation and safeguarding your margins.

Step 1: Remove Old Coverings & Skirtings

Man using hammer and crowbar to remove old laminate floor panels

Start by clearing the existing flooring:

  • Remove carpets, vinyl, laminate or tiles
  • Strip away old adhesives
  • Carefully detach skirting boards (you can reuse or replace them later)
  • Extract any staples, nails, or fixings still embedded in the floor

A clean, exposed surface makes it easier to inspect and assess the condition of your subfloor.

Step 2: Inspect & Repair Structural Issues

man with white hard hat assesses wood flooring with flashlight

With the old coverings gone, it’s time to assess your subflooring.

For Wooden Subfloors:

  • Look for signs of rot or water damage
  • Secure loose or squeaky boards with screws
  • Consider using plywood overlays for added strength and flatness

For Concrete Subfloors:

  • Fill in cracks using a concrete repair compound
  • Check for uneven surfaces or signs of crumbling

This is a critical step - structural weaknesses left unchecked will cause problems with your new flooring down the line.

Step 3: Clean Thoroughly

person using hoover to clean subfloor

Before proceeding, clean the subfloor surface meticulously:

  • Sweep or vacuum dust and debris
  • Remove grease, oils, or any residue that might affect adhesion
  • Allow the area to fully dry

Even minor debris or moisture can prevent proper bonding and reduce the lifespan of the new flooring.

Step 4: Perform Moisture Testing

builder using a moisture tester on floor

Moisture is a major enemy of flooring, especially for wood and laminate options. Use a moisture meter to check levels across the surface.

  • Readings between 5%-12% are generally safe, but always refer to the flooring manufacturer’s guidelines
  • Pay special attention to areas near walls, plumbing, or concrete foundations

If moisture levels are too high, install a moisture barrier or investigate further for underlying issues.

Step 5: Level and Smooth the Subfloor Surface

spirit level on floor

Uneven subfloors cause uneven flooring. Check the entire area using:

  • A spirit level or straight edge
  • A digital laser level for more accuracy

Levelling Solutions:

  • Use hardboard or plywood sheets for wooden subfloors
  • Apply self-levelling compound or foam underlay on concrete

Make sure the surface is flat, smooth and ready to take on the new flooring material.

Step 6: Install the Right Underlay and Moisture Barrier

man installing foam floor underlay

Choose the right underlay based on the chosen flooring type and room usage:

  • Laminate & Engineered Wood: Use foam or rubber underlay with built-in moisture protection
  • Vinyl & LVT: Opt for thinner underlays to maintain stability
  • Wet Areas: Always install a dedicated moisture barrier according to the manufacturer's instructions

Proper underlay not only enhances comfort and insulation but also extends the lifespan of your client's flooring.

Final Subfloor Checks Before Installation

wood flooring from a low perspective

Before installing the new floor, double-check the following:

  • Moisture levels are within acceptable limits
  • The surface is level and smooth
  • No squeaky or loose sections remain
  • All tools and materials are ready for installation

Taking the time now to ensure everything is perfect avoids unnecessary disruption once the flooring is laid.

Conclusion

Effective subfloor preparation is a crucial part of any flooring project. From removing old materials and checking for damage to levelling and moisture protection, every step plays a role in the success and durability of your installation.

At Leader Trade, we know that professional results start with proper groundwork. Preparing the subfloor correctly is the best way to ensure the new floor looks great and lasts for years to come.

Ready to get started? Explore our range of flooring underlay and flooring installation tools today.

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