NWFA Certified · Metro Detroit
Subfloor Leveling and Repair Built for Michigan Homes
A premium floor is only as good as its foundation. We engineer the invisible work that most contractors skip. Laser-precision flatness, structural correction, and moisture mitigation for Metro Detroit homes.
The NWFA Standard
The Critical Difference Between Flat and Level.
There is a massive difference between a floor being level and a floor being flat. An older home may slope slightly and that's okay. But to successfully install hardwood or premium LVP, the subfloor must be perfectly flat. According to NWFA guidelines, that means within 1/8 of an inch over a 6-foot span, or 3/16 of an inch over 10 feet.
If your subfloor has dips, crowns, or peaks outside those tolerances, your new flooring will flex, squeak, and eventually fail. We use precision 10-foot straight edges and advanced lasers to verify every square foot before a single plank is laid.
Structural Engineering
More Than Surface Level: Structural Integrity & Deflection.
A perfectly flat floor requires a structurally sound foundation. Before any leveling begins, we evaluate joist spacing and subfloor thickness to ensure they meet NWFA deflection standards. We also calculate point loads the physical weight your structure can safely handle.
⚠ Engineering Warning
Pouring self-leveling underlayment adds massive "dead load" to your home's framing. Standard contractors often pour thousands of pounds of cement without checking joist capacity risking severe structural sagging. We calculate the exact weight loads, and for complex projects, we collaborate directly with licensed Structural Engineers to guarantee your home remains safe and stable.
Our Arsenal
Four Methods of Subfloor Correction.
We approach every subfloor as carpenters and engineers. We diagnose the issue first, then prescribe the exact correction method your home needs:
Carpentry & Joist Repair
Sometimes the problem starts at the bones. We remove the subfloor to plane or sister uneven joists. Resolving severe structural dips and crowns at the source, not just masking them.
Mechanical Grinding
Swollen OSB seams, high plywood joints, concrete peaks. We aggressively sand them down to tolerance. It's unglamorous work, but it's the difference between a floor that lasts and one that squeaks within a year.
The Hard Shim Method
A highly specialized carpentry technique we use to permanently build up low spots with layered plywood, wood shims, and elastomeric glue. Without adding the massive water weight of cementitious patches.
Advanced SLU (Self-Leveling)
Precision-poured, high-tech self-leveling compounds that create a perfectly flat, glass-like foundation. This is our go-to for large-scale corrections. When executed properly, it's the gold standard.
Material Science
The Science of SLU: Why Standard Contractors Fail.
Pouring self-leveling underlayment is a chemical science, not a DIY project. Wood subfloors naturally flex, and if you use the wrong patch, it will crack and destroy your new floor. We strictly use premium, polymer-modified compounds from industry leaders like Schönox, Ardex, MAPEI, Bostik, and Uzin. The chemistry has to be right.
The Primer Rule
Proper bonding requires exact primer chemistry. We specify primers based on the porosity of your concrete or the type of plywood. Ensuring the underlayment has the right emulsifiers to flex and bond permanently with your home's specific structure.
From the Field
Primer → Pour → Perfection.
A complete subfloor correction sequence: specialized bonding primer over existing mastic, precision SLU pour, and the finished 8-inch hickory hardwood.
Bonding Primer Over Mastic
Livonia, Michigan
Engineered SLU Pour Glass Finish
Livonia, Michigan
Custom 8″ Hickory Michigan Plank Fireside
Livonia, Michigan
Bare Subfloor Evaluation
Northville, Michigan
Specialized Blue Bonding Primer
Northville, Michigan
Needle Rolling SLU The Money Shot
Northville, Michigan
Licensed Residential Builder
Subfloor work often requires a completely cleared workspace — more so than any other phase of a flooring project. We coordinate professional furniture removal and appliance disconnection by licensed plumbers before a single bag of SLU is mixed. The subfloor gets the access it needs. The work gets done correctly.
Case Studies
Project Spotlights: Subfloor Engineering in Action.
1.5-Inch Structural Correction & Silica Dust Control
How our 8-man crew safely executed a massive 1.5-inch correction using HEPA-filtered mixing stations.
View Project DetailsPrecision Flatness for 8-Inch Walnut
Engineering a flawless, glass-like subfloor to meet strict NWFA tolerances for custom wide-plank walnut.
View Project DetailsSmart Encapsulation & Custom Hickory
Bypassing hazardous mastic grinding with specialized bonding primers and engineered underlayment.
View Project DetailsDon't let a bad subfloor ruin
a $20,000 investment.
Connect directly with Michigan's NWFA Certified team to evaluate and correct your subfloor before your next flooring project.
Related Services
The subfloor is step one. Here's step two.
Google Reviews
What your neighbors are saying
"1 Wood Floors installed a wide plank white oak floor and the craftmanship and service was outstanding! Our original floors were not flat or level. 1 Wood Floors was able to correct the problem and install beautiful floors."
"Fast forward to my third project with One Wood Floors! Every project has been completed with the highest level of quality and professionalism.… This project involved a floor that had significant settling that Aaron painstakingly resolved. I only shopped one place for this project because I knew it would be done correctly."
"Our installer Aaron was very professional, he set the standard by which everyone will be judged against. He cleaned up everyday and the way he put the extra effort in to level and prep our floor (the right way) made us very glad that we got our flooring here. They make the floors themselves and the product speaks for itself."
"There was a specific concern at end of our hallway where there was at least a 1.5inch drop and we needed it leveled.… He listened to my concerns, which included not only the leveling issue, but the moisture content in our home.… Ed was/is an installer himself which I believe makes him the best at inspecting a project and giving his recommendation."
Subfloor Leveling FAQs
Subfloor questions answered.
An improperly prepared subfloor is the single leading cause of hardwood floor failures. Squeaks, hollow spots, cracked locking systems, and finish separation all trace back to subfloor problems. We engineer your foundation using laser topography and premium self-leveling compounds to meet strict NWFA flatness tolerances.
Common signs include squeaky floors, visible unevenness, hollow spots when you walk, or doors that don't close properly. Many subfloor problems are invisible to the untrained eye. We perform a full diagnostic evaluation on every project before installation begins.
SLU is a cementitious compound that we pour over your existing subfloor to create a perfectly flat surface. It flows like water and self-levels using gravity, but requires precise mixing ratios, temperature control, and expert application. We use premium Schönox products for all our SLU work.
Standard pours range from 1/8 inch to 1 inch. For deeper corrections, we've completed pours up to 1.5 inches using specialized techniques and multi-layer applications. Our Ann Arbor project involved a massive 1.5-inch correction across a full home.
Mixing cementitious materials creates hazardous silica dust. We utilize on site HEPA-filtered Collomix mixing stations to guarantee zero airborne silica reaches your living space. This is a critical health and safety measure that most contractors skip entirely.