Services
Subfloor preparation and self-leveling
Does my subfloor need to be leveled before installing hardwood?
The NWFA flatness tolerance is 3/16 of an inch over 10 feet for most installations, and tighter for wide plank. Concrete slabs in new high-rise construction routinely miss it. If the subfloor is out of tolerance the floor will telegraph every dip, hollow-sound underfoot and eventually fail at the joints, and no installation technique compensates for it.
- Flatness target
- 3/16" over 10 ft (tighter for wide plank)
- Method
- Cementitious self-leveling over primed slab
- Prerequisite
- In-situ RH probe test per ASTM F2170
- Deliverable
- Written flatness and moisture readings
We measure before quoting, with a straightedge and a laser, and we put the readings in writing. A leveling scope discovered mid-install is the single most common source of change orders in this trade.
Cementitious self-leveling compound is poured over a primed slab. Depth drives cost far more than area does — a large flat room is cheap to correct, a small badly dished one is not.
Moisture testing comes first. Pouring leveler over a slab with high relative humidity traps the moisture underneath and moves the failure downstream rather than solving it.
On plywood over joists the answer is usually not leveler but sistering, shimming or a plywood overlay. Flooding a wood subfloor with cementitious compound adds dead load and does not address deflection.
Where we do this work
Subfloor preparation and self-leveling is available throughout New York County (Manhattan), Kings County (Brooklyn), Queens County, Bronx County, Richmond County (Staten Island), Westchester County, Hudson County, Essex County, Union County, Bergen County, Passaic County, Monmouth County, Middlesex County, from the showroom at 1809 NJ-35, Oakhurst, NJ.