When I decided to install new flooring in my home, I thought the hardest part would be choosing the material. Hardwood? Vinyl? Laminate? I spent hours comparing samples and prices. But what I didn’t realize was that the real key to success wasn’t just picking the right flooring—it was making sure the surface underneath was ready.
Subfloor preparation isn’t the flashy part of home improvement, but it’s one of the most important. Whether you're going DIY or hiring pros, skipping or rushing this step can lead to flooring that looks bad, wears out early, or even starts to fail within months.
In this blog post, I’ll walk you through what I learned about subfloor prep, why it matters, and what steps to take to make sure your new floors last.
Let’s start with the basics. A subfloor is the layer beneath your actual flooring. It's usually made of plywood, concrete, or OSB (oriented strand board), and it provides the structural support for whatever flooring you install on top.
Think of the subfloor as the foundation for your floors. Just like you wouldn’t build a house on shaky ground, you shouldn’t lay new flooring on a damaged or uneven subfloor.
Most homes have one of the following types:
Each one needs a different approach when it comes to prep, but both require careful inspection.
Skipping subfloor prep is like painting over a cracked wall without fixing the cracks. It might look okay at first, but problems will show up quickly.
Here’s what can go wrong if you don’t prepare the subfloor properly:
Trust me, nothing is more frustrating than installing brand-new floors only to hear creaks every time you walk across them or notice boards lifting at the edges.
Before you lay down anything new, you need to inspect what’s already there. Here's how I did it:
This part can get messy, but it’s necessary. I pulled up my old carpet and laminate to expose the subfloor. Once it was clear, I vacuumed thoroughly so I could see what I was working with.
Check for:
If any of these are present, you’ll need to fix them before moving forward.
Moisture is one of the biggest threats to flooring. I used a moisture meter, which you can buy or rent from a hardware store. Most flooring manufacturers list acceptable moisture levels in their installation guides.
If the reading is too high, you may need a vapor barrier or dehumidifier to dry the space before continuing.
This step surprised me. Even a tiny dip or bump can cause flooring to install poorly. I used a 6-foot level and moved it across different parts of the room.
A general rule is that your subfloor should be no more than 3/16 of an inch off over a 10-foot span. If it’s more than that, it’s time to level things out.
If your subfloor isn't level, you have a few options. The method depends on what kind of subfloor you have.
I had a mix of both in my home, and it took a full weekend to get the surface ready. But once I did, the actual flooring install went smoothly.
If you’re tackling this on your own or just want to understand what’s going on when the pros arrive, here are some helpful things to keep in mind:
Don’t rush subfloor prep. It’s not fun, but it’s way easier to fix problems now than after your flooring is down.
You’ll need a level, moisture meter, sander or grinder, and possibly leveling compound. Renting tools is a smart option to save money if you’re not planning to use them again.
Every flooring product has different requirements for subfloors. Follow the manufacturer’s instructions so your warranty stays intact.
Even if your subfloor looks dry, measure the moisture. High levels can destroy hardwood and cause vinyl to lift.
If you’re hiring someone, don’t be afraid to ask questions. A good installer will always inspect the subfloor before laying anything down.
Expect them to:
Some contractors include minor prep in their pricing. Others charge extra for leveling or moisture barriers. Make sure you ask what’s included up front.
Also, a professional will know when a subfloor is beyond repair and needs replacing. That may cost more, but it's better than paying twice when your new floor starts to fail.
I used to think subfloor prep was optional. Now I know better. Installing new flooring is a big investment, and without a solid base, that investment can go to waste.
After spending the time to sand, patch, level, and dry my subfloor, the installation went smoothly. My floors feel solid, look great, and haven’t had a single issue since. That peace of mind is worth every minute I spent getting it right.
Whether you're doing a DIY project or hiring professionals, don’t cut corners. Follow this subfloor preparation guide and give your flooring the strong start it needs.
We proudly serve communities across Utah, including Bluffdale, Draper, Utah County, and beyond. No matter where you are, Silver Bullet Construction delivers expert craftsmanship and tailored solutions to meet your construction and remodeling needs.
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