Floor Preparation for Hardwood: The Steps Most Crews Skip
Seven things that happen between removing the old floor and installing the new one. Get these right and the floor lasts. Skip them and it will tell you.
Prefer to read? The full breakdown is below, same seven points in the same order.
Why what is under the floor matters more than the floor itself
The product you choose gets most of the attention. The subfloor it rests on gets almost none. That is backwards. A premium hardwood floor installed over a poorly prepared subfloor performs like a budget floor. A mid-range floor installed over a properly prepared subfloor performs the way it was designed to for twenty years.
Here are the seven steps of proper floor preparation, in the same order Andre covers them in the video.
Seven preparation steps
Same Points as the Video
Reference this any time you want to revisit what Andre covered. Share it with whoever else is part of the decision.
1
Assess the Subfloor Before Anything Else
Before any prep work begins, a thorough inspection of the existing subfloor is required. Identify the subfloor type: plywood, OSB, concrete, or existing hardwood. Each has different preparation requirements and each affects which flooring products are appropriate for installation above it.
Check moisture content with a meter, not by looking at it. Concrete subfloors in particular can read as dry on the surface while releasing significant moisture vapor from below. Check flatness with a 10-foot straightedge. Any deviation exceeding 3/16 of an inch over 10 feet needs to be addressed before installation begins.
We assess subfloor type, moisture, and flatness on every job using measuring tools, not visual inspection. The findings determine the product recommendation and the installation method, not the other way around.
2
Repair and Reinforce Before You Level
Squeaks, loose fasteners, soft spots, and damaged sections need to be addressed before any leveling work begins. A squeaky subfloor panel that gets covered with leveling compound is still a squeaky subfloor panel. The squeak transfers through the compound and into the finished floor above it.
Tighten loose screws and nails. Add additional fasteners where panels have shifted. Replace sections with rot or significant damage. In some cases, a layer of plywood underlayment is the right answer for subfloors with large gaps or severe unevenness that goes beyond what leveling compound can address.
We fix squeaks and secure loose panels before we quote any leveling work. These are basic preparation steps, not extras.
3
Control Moisture Before It Controls the Floor
Moisture is the primary cause of hardwood floor failure over time. A vapor barrier between the subfloor and the hardwood is required in areas with elevated moisture readings, particularly over concrete and in below-grade installations. Using a hygrometer to monitor indoor relative humidity during and after installation helps prevent moisture fluctuations that cause wood to move after the floor is down.
Maintaining a stable indoor humidity between 35 and 55 percent throughout the year is the best long-term protection for any wood-based floor. Seasonal swings outside that range cause gapping in dry conditions and crowning in wet ones, regardless of how well the floor was installed.
We measure subfloor moisture and indoor humidity before any hardwood installation begins. If the readings are outside acceptable range, we address the source before the floor goes down.
4
Choose the Right Underlayment for the Specific Install
Underlayment is not padding. It is a functional part of the flooring system that affects moisture protection, sound transmission, and how the floor feels underfoot. The wrong underlayment under the right product causes problems the product was designed to avoid.
Tar paper is a traditional moisture barrier used under nail-down hardwood installations. Foam and cork underlayments provide cushioning and sound reduction, particularly relevant in condos and multi-story homes with HOA noise requirements. The right choice depends on the subfloor type, the installation method, the specific product, and the building's sound requirements.
We specify underlayment as part of the installation plan, matched to the product and the conditions. It is not a day-of decision made from whatever is on the truck.
5
Sand and Level to Specification
High spots are ground down. Low spots are filled with a leveling compound appropriate for the subfloor type. Both steps require the right tools: a floor grinder for concrete high spots, a belt sander or hand sander for wood subfloor ridges, and a self-leveling compound poured into low areas and allowed to cure fully before any flooring proceeds.
Cure time is not negotiable. Most leveling compounds require 24 hours before installation can begin. Some require longer depending on the product and pour depth. Compressing this timeline is how leveling work fails, and a failed leveling compound under a finished floor is one of the hardest problems to fix after the fact.
Leveling is quoted separately from materials and installation because it cannot be accurately assessed until the existing floor is removed. We show you the findings and get your approval before any leveling work begins.
6
Inspect and Clean Before Installation Starts
After all prep work is complete, a final inspection and thorough cleaning are required before the first plank goes down. Debris, dust, and remnants of the prep process left on the subfloor create imperfections in the finished floor above them. Even small particles under a floating floor create pressure points that affect how planks lock together.
Sweep, vacuum, and walk the entire subfloor one more time. Confirm flatness measurements are still within tolerance, particularly if leveling compound was poured and cured. Confirm moisture readings have not changed since the initial assessment.
We do a final walkthrough of the subfloor before installation begins. This is the same inspection process we do on the finished floor at the end of the job, just at the foundation level.
7
Acclimate the Hardwood While Prep Is Running
Hardwood needs time to adjust to the temperature and humidity of the specific room where it will be installed. Engineered hardwood typically needs 48 to 72 hours. Solid hardwood may need longer. The floor should be stacked with spacers to allow air circulation on all sides. Boxes left sealed in a corner do not acclimate.
The practical benefit of running acclimation in parallel with subfloor prep is that the two timelines overlap. When the subfloor leveling compound has cured and the subfloor is ready, the wood is ready too. No additional waiting. The project moves efficiently without compressing either step.
We deliver hardwood before installation begins and acclimate it in the room while subfloor work is completing. The floor goes down when both the wood and the surface are ready. Not before.
"A floor is only as good as what it rests on. Preparation is not a step before the job. It is the job."
Redeemed Flooring | Concord, CA | In Bay Area homes since 1999
What this means for your project
Every one of these seven steps takes time. A crew focused on speed skips the ones that are hardest to see. The squeaks get covered. The moisture gets ignored. The leveling cure time gets compressed. The acclimation gets skipped. None of it is visible on day one. All of it shows up within the first year.
If you watched the video and want to talk through what proper floor preparation looks like for your specific home and subfloor conditions, the in-home estimate is the right next step. We walk every subfloor, document what we find, and show you the findings before any installation decision is made.
Want a crew that treats the subfloor as seriously as the surface?
We walk every subfloor, check moisture and flatness, and show you what we find before anything is scheduled. The preparation is where the floor is won or lost.
