Whether you're tackling a new flooring project for your home or flipping a property, the key to a smooth and successful flooring installation starts before you even lay the first board.
Proper subfloor preparation is critical for ensuring your new floor looks great and lasts for years to come. As an experienced flooring retailer and installer, I've seen plenty of projects where a little extra prep work made all the difference.
Here’s how you can prepare your subfloor for a perfect DIY flooring installation.
1. Assess Your Current Subfloor Condition
Check for Levelness
One of the first things you should do is check that your subfloor is level. Uneven subfloors can cause all sorts of issues, from gaps in vinyl flooring to creaks and misaligned planks in timber or laminate.
Here’s how to check: grab a spirit level and run it across your subfloor, checking for any dips or bumps. If it’s not level, you may need to use a self-levelling compound to even things out. It’s a little bit of extra work, but trust me—it’s worth it to avoid bigger problems down the line.
Inspect for Damage or Moisture
Next, you’ll want to inspect the subfloor for damage or moisture issues. Timber subfloors can develop cracks or rot, while concrete subfloors might have chips or signs of water damage.
One of my clients once skipped this step and installed laminate flooring over a subfloor that had a hidden moisture problem. Within a few months, the flooring started to warp, and the entire room had to be redone. To avoid this, use a moisture meter to test the levels—especially if you’re installing timber or laminate flooring, which are sensitive to moisture.
2. Clean the Subfloor Thoroughly
Before you do anything else, make sure the subfloor is clean and free of dust, debris, or old adhesive. Even the smallest bits of grit can cause bumps under vinyl or laminate, leading to an uneven surface.
I remember a renovation project where the homeowners were installing vinyl planks but skipped the cleaning step. A few months later, they noticed tiny bumps in the flooring, all caused by small debris that was left behind. To avoid this, sweep and vacuum thoroughly, and use a scraper or adhesive remover to clean off any old glue.
3. Repair Any Imperfections
Fix Cracks and Holes
If your subfloor has any cracks, holes, or chips, now’s the time to fix them. These imperfections can lead to dips or raised areas in your new flooring, causing an uneven installation. For concrete subfloors, use a filler or patching compound to repair any cracks or holes.
Secure Loose Boards
If you’re working with a timber subfloor, check for any loose or squeaky boards. These can cause your flooring to move or make noise when walked on. Tighten them up by using screws or nails to secure them firmly to the joists.
4. Ensure Subfloor Dryness and Ventilation
Moisture is the enemy of most flooring types, especially timber and laminate. If you’ve had any moisture issues with your subfloor, ensure it’s completely dry before installing your new flooring. If it’s a concrete subfloor, allow any repairs to fully dry out, which can take a few days.
Good ventilation is crucial, too. If moisture gets trapped under your new flooring, it can cause warping or mould. Let the subfloor breathe and ensure it’s completely dry.
5. Install the Right Underlay
Choose the Right Underlay for Your Flooring
Underlay isn’t just optional; it’s a critical part of the installation process that affects the longevity and comfort of your floor. It acts as a moisture barrier, provides cushioning, and improves insulation.
- For timber flooring, a foam or rubber underlay is ideal, as it provides cushioning and helps with soundproofing.
- For laminate flooring, a vapour barrier underlay can protect against moisture and improve stability.
- For vinyl flooring, especially in areas prone to moisture like kitchens or bathrooms, a foam underlay can provide extra comfort underfoot while also serving as a moisture barrier.
The right underlay can make a huge difference in how your floor feels and performs, so don’t skip this step.
6. Address Subfloor Movement
For Timber Subfloors
If your subfloor has any movement or feels a bit springy, now’s the time to fix it. Subfloor movement can cause your new flooring to creak or separate over time. Reinforce any loose or squeaky sections with screws or nails to secure them tightly to the joists.
For Concrete Subfloors
Concrete subfloors generally don’t move, but cracks can cause problems. If you find any cracks, fill them with a crack isolation membrane to reduce the risk of the cracks expanding over time and affecting the new flooring above.
7. Acclimate Flooring Materials
This is an often-overlooked step, especially for timber and laminate flooring. These materials need to acclimate to the room’s temperature and humidity to prevent buckling or expanding after installation.
Here’s what you do: leave your timber or laminate planks in the room where they’ll be installed for at least 48 hours. Open the boxes so the planks can adjust to the environment. One of my clients once rushed the installation process without acclimating the planks, and they ended up with gaps and uneven boards after a few weeks. Don’t skip this—patience pays off!
Conclusion
Subfloor preparation may not be the most exciting part of your DIY flooring project, but it’s arguably the most important. Taking the time to assess, clean, repair, and ensure proper ventilation will make your installation smoother and help your new floor last for years to come.
Remember, the better your prep work, the better your final result. If you’re ever unsure about a step or need advice on the best underlay for your flooring type, don’t hesitate to reach out. Whether you’re a builder, renovator, DIYer, or home flipper, prepping your subfloor correctly is the foundation of a professional-looking and long-lasting floor. Happy installing!