Hardwood Under the Carpet: How to Check, and What It Takes to Restore It

A large share of the houses built across the DMV between the 1920s and the late 1960s went up with oak strip flooring in every room. Then wall-to-wall carpet came into fashion, and for a few decades it was laid straight over that oak in living rooms, bedrooms and hallways from Silver Spring and Wheaton to Arlington and Falls Church. A lot of it is still there, and a lot of homeowners are walking on carpet without knowing what is a half inch below it.

If you are about to replace carpet, or you have just bought a house with carpet you do not love, it is worth ten minutes to find out what is underneath before you spend anything. Here is how to check, what condition to expect, and what it takes to bring that floor back.

How to check without pulling up a room

Lift a floor register. If the house has floor vents, this is the easiest look you will get. Pull the metal register out and look at the cut edge of the floor around the duct. You will see the layers in cross section: carpet, pad, and then either the ends of tongue-and-groove boards or the edge of a plywood sheet.

Pull a corner in a closet. Carpet is held at the edges by tack strips, and it releases from them with a firm pull using pliers. A closet corner is the right place because it presses back down easily and nobody sees it if it does not. Fold back the pad as well; it is usually stapled rather than glued.

Look at doorways and stair landings. Where carpet meets tile or vinyl at a threshold, the metal transition strip often hides a visible board edge. The top of a staircase is another place where the floor construction shows.

Use the age of the house. Built before about 1970 inside or near the Beltway, hardwood under the carpet is more likely than not. Built later, plywood or particleboard underlayment is the norm, because by then builders knew carpet was going on top and stopped paying for oak nobody would see. Additions and enclosed porches on older houses are usually plywood too, even when the rest of the floor is oak.

What you are likely to find

Most often it is red oak strip, two and a quarter inches wide and three quarters of an inch thick, nailed to a board subfloor. In houses from the 1920s and 1930s you may find narrower strip, white oak, or heart pine on upper floors. Our guide to oak and other species explains how to tell them apart, and it matters if any boards need replacing.

Because carpet went down when these floors were fairly young, many of them have been sanded once or never. That leaves close to a full wear layer above the tongue, which is more than can be said for plenty of floors that stayed exposed. It is one of the reasons we so often advise refinishing rather than replacing.

What decades under carpet does to a floor

Carpet protects wood from traffic and sunlight, so the boards themselves tend to be sound. What you will see is a predictable set of marks, and most of them are cosmetic.

• Tack-strip holes around the perimeter. Two rows of small nail holes a few inches off every wall. They are filled during refinishing and mostly end up under or near the shoe molding.
• Hundreds of pad staples. Every one has to come out before a sander touches the floor, because a staple tears sanding belts and leaves a gouge. It is slow work and there is no shortcut.
• Pad residue. Old foam and rubber pad breaks down and can bond to the finish in patches. It sands off, but it loads abrasives quickly.
• Paint drips and overspray. Painters do not mask a floor that is about to be carpeted. It all sands out.
• Ambered old finish. The original finish will have yellowed or darkened. Sanding removes it entirely and the raw oak underneath is lighter than most people expect.

The problems that actually matter

Pet stains. This is the big one. Carpet hides accidents, the pad holds the moisture against the wood, and urine reacts with the tannins in oak to turn it black. A stain that has gone through the board does not sand out and does not reliably bleach out. The fix is to cut out the affected boards and weave in matching replacements, which we cover in our hardwood repair guide. One or two spots is routine. A room where a pet had free rein for years is a different conversation.

Water damage. Check under windows, beside exterior doors, around radiators and anywhere a houseplant sat. Gray staining usually sands out; soft, dark or crumbling wood does not. If the boards are cupped, read what to do with water-damaged hardwood before anyone sands anything.

Plywood patches. When a wall was moved, a floor furnace removed or a closet added, the hole was often filled with plywood because carpet was going over it anyway. The same goes for old floor-vent openings. These get filled with real boards laced into the surrounding floor.

Rooms that were never hardwood. Kitchens and bathrooms in these houses were usually built with a different subfloor, and additions almost always were. It is common to find oak in most of the house and none in one or two rooms. New boards can be installed there and the whole level finished together so it reads as one floor.

Do not skip this if the house is older

If what you find under the carpet is not wood but old resilient tile or sheet flooring, stop and do not scrape it. Nine-inch floor tiles and the black adhesive beneath them in mid-century houses frequently contain asbestos. Left alone and intact they are not a hazard; sanding or chipping them is. Have the material tested, and have it removed by a licensed abatement contractor if it needs to come out.

For houses built before 1978, the old floor finish and nearby painted trim may contain lead. Tell your contractor the age of the house so dust containment is planned accordingly.

What bringing it back involves

1. Carpet, pad, staples and tack strips come out and are hauled away. Baseboards usually stay; shoe molding usually comes off. See baseboards and shoe molding for what happens at the wall.
2. The floor is inspected with everything exposed. Loose boards are refastened, squeaks addressed, and damaged or stained boards are replaced.
3. The floor is sanded to bare wood in several passes, filled, and sanded again. Our sanding process guide walks through each pass.
4. Stain, if you want it, then finish coats. Bare oak can go natural, light, or dark, and the choice of stain color and finish and sheen is entirely open. Nothing about the old color carries over.

Timing runs the same as any refinish, with a day added at the front for removal and prep in a larger house. Our guide to how long refinishing takes has the day-by-day version.

What about the stairs?

Stairs are the one place to keep expectations in check. In many of these houses the treads under the carpet are oak and refinish beautifully. In others, especially where the stairs were always meant to be carpeted, they are construction-grade pine or plywood that was never intended to be seen. Pull the carpet back on one tread before planning around them. Our stair refinishing guide covers both cases.

When covering it back up is the right call

We would rather tell you than sell you a refinish that disappoints. If the floor has widespread black staining, has been sanded down to the nail heads, or has large areas of rot, restoring it may cost more than it returns. In that case the oak still makes an excellent, flat base for new flooring over the top. That is the exception, though. In most DMV houses of this era, the best floor you can buy is the one you already own.

Frequently asked questions

Not sure what you have? Request a free in-home estimate. We will lift a corner, check the species, the thickness left above the tongue and any staining, and tell you plainly whether the floor under your carpet is worth bringing back.