Subfloor Preparation: The Line That Decides Your Flooring Bill
The surface is what you choose. The subfloor is what you pay for. It is the single most common reason two quotes for the same material are hundreds of dollars apart.
What is under an Arkansas floor
Plywood or OSB over joists
The standard from roughly the 1970s onward, which covers the majority of Arkansas housing. Lift a floor register and look at the cut edge: plywood shows thin layers, OSB shows compressed chips. It is the most accommodating substrate there is and takes every material on this site.
Plank decking
Boards laid across the joists, found in prewar housing — Pine Bluff, Fort Smith, older Little Rock. At a vent you will see individual boards with gaps rather than a continuous sheet. It takes nailed solid hardwood and carpet directly; everything else wants an underlayment or a plywood overlay first.
Concrete slab
Common in postwar and newer construction. Tap it — no hollow sound, no movement. It takes tile, stone, rigid-core vinyl and engineered wood, and solid hardwood not at all.
What preparation costs
- Underlayment over plank — roughly a dollar a square foot.
- Plywood overlay — two to four, and it costs you height at doors and at the bottom stair riser.
- Levelling a slab — anything from nothing to more than the flooring, depending on how flat it is.
- Replacing damaged decking — the line that is missing from most quotes, and the one worth agreeing a rate for in advance.
Flat, sound, dry — in that order
Flat matters most for rigid and floating floors: tile cracks over a floor that moves, and vinyl telegraphs a dip as a hollow spot you hear underfoot. Sound means nothing soft, nothing loose, nothing that gives. Dry matters most over concrete and before any wood product goes down.
A level, sound, quiet subfloor makes a mid-range surface feel expensive. No premium material rescues a floor that moves. When the budget is tight, that is the order the money should go in.
The five-minute check before you get quotes
- Lift a floor register and look at the cut edge of the material.
- Walk the room barefoot and feel for give — along walls, in front of the dishwasher, around toilets and tubs.
- Look for a slope with a marble or a level.
- Tell every installer what you found, before they quote rather than after.
Common questions
Can I put new flooring over the old one?
Sometimes, if the old floor is flat, sound and firmly attached and the height works at doors. It saves removal cost and it inherits the old floor’s problems.
How do I know if a quote includes preparation?
Ask what it assumes about the subfloor and what happens if that assumption is wrong. A quote with no answer has not priced it.
Is self-levelling compound a fix?
For an uneven slab, often yes. For a framed floor that deflects, no — that is a framing problem and compound will crack over it.