Cost to Replace Plywood Subfloor

When a home’s subflooring becomes rotted due to a roofing or plumbing leak, the entire subflooring must be removed and replaced. This is a safety issue, so it should not be left for another day.

By the time the homeowner notices it, the complete subfloor removal and the subfloor repair or replacement costs a cost, and rotting has probably reached the point where there’s a risk of someone stepping through the floor, especially if they are a bit on the heavy side.

Replacing a damaged subfloor can be a more challenging home repair task, especially in a bathroom, which is the most likely place to find damaged subflooring.

The tight confines of a bathroom make the project particularly challenging, mainly if the floor joists aren’t laid out in such a way as to provide ready support for the repairs that need to be done.

For this reason, some homeowners might pay a carpenter to come in and make the repair, even with labor costs, if they are do-it-yourselfers.

Most will charge for this sort of a project on a time, labor cost, and materials basis, rather than a straight bid, simply because they don’t know how serious the problem is or how much they’re going to cost to replace or have to repair until they cut into the floor and remove the damaged part. By then, it’s too late to be giving a bid.

So, what much per square foot does that cost? Depending on the materials used, it can be a total cost of anywhere from $2 per square foot to $10 per square foot, depending on the type of subfloor. The one-per-square-foot cost will be higher if any sister’s joints need to be added to support the new subflooring.

The various labor costs will usually run somewhere between $25 per hundred square feet per foot and $30 per square foot per hour, with a small one per fifty-five square feet foot repair taking anywhere from an hour to three hours to complete. Larger one per hundred five square feet repairs would, of course, cost more.

Common Subfloor Materials

Not all homes are built with the same sort of subflooring. Construction methods and cost to replace the subflooring have changed with time, with some older ways being set aside due to style and cost factors, such as newer construction materials taking over part of the subfloor of the market.

Both the kind of subfloor material used and the most common subfloor repair cost and replacement cost depending on the material being chosen for making the new subfloor, and repair cost, are factors to be considered for strength, appearance, and cost to replace subfloor materials again.

Plank Subflooring

Plank subfloor flooring materials cost to replace plywood subfloor-ing was the standard common subfloor material and home construction method for years. I’m not referring to hardwood floors here, but the typical cost to replace plywood subfloor material rather than pine floors.

Plank subfloor cost as flooring material was used in homes where the expense of hardwood floors was not desired. But in the 1950s, plywood subfloors took over from hardwood subfloor types and softwood subflooring.

When replacing plank subflooring, the final appearance desired to replace plywood subfloors is a critical consideration. If the whole subfloor replacement part is going to be covered by carpeting, linoleum, or laminates, then the appearance of the entire subfloor replacement part isn’t essential.

But in the case of hardwood floors, inserting plywood or OSB in the subfloor replacement cost to replace plywood in the subfloor replacement cost or to replace plywood subfloor in subfloor replacement cost depends on the place of new hardwood can destroy the look of the engineered wood floor.

Plywood Subflooring

Plywood subflooring is the gold standard of a subfloor for modern home construction, offering strength, quality, and reasonably good moisture resistance.

Nevertheless, unless pressure-treated moisture barrier, resistance or moisture barrier, plywood subfloors is used (and that’s not common), it is subject to water damage, especially with a consistent leak. Plywood subfloor repairs can be replaced with a treated moisture barrier, resistant plywood subfloor, or oriented strand board (OSB).

OSB Subflooring

OSB has taken over from plywood in much modern construction, especially where cost is a factor. Technically as strong as softwood plywood, the same thickness of OSB as plywood is permitted in the building code.

However, OSB is not as water-resistant as plywood and is more likely treated plywood to soak moisture resistance and up moisture, especially around the edges, leading to damage. OSB can be replaced with more moisture-resistant OSB or with a more moisture-resistant and resistance barrier-treated plywood.

Concrete Subflooring

A home built on a concrete slab will have a concrete slab and subflooring on the ground floor. This is not subject to water damage, so the chances of replacing a concrete slab and subfloor or slab replacing subfloors with concrete or even replacing the subflooring itself are minimal.

Should it become damaged, chances are pretty good that the home itself has become structurally sound and severely damaged, needing much more than a simple concrete slab and subflooring repair.

Installing plywood: the cost to replace old subflooring, Ken Dyck

What’s Involved in Subfloor Repair?

To understand why replacing a subfloor can be so expensive, it’s helpful to understand what’s involved in the entire subfloor replacement process. Starting from the carpenter arriving on site, they will have to determine the extent of the damage.

That means removing floor covering interior drywall and sometimes the baseboard, as well as making or enlarging the existing hole, seeking out the extent of the damage. It is necessary to remove all of the rotten wood, as far back as the cost to replace the subfloor with plywood, replace the subfloor as it goes.

This often means removing more old subfloor for the new subfloor for replacement or removal than just the rotted subfloor wood, as it is necessary to go back to the floor joist, cutting the old subfloor down to the middle of the wood bonded to the new subfloor and joist so that there is something to support the new subflooring that is being installed.

In some cases, the floor joists can be rotted as well. Even a tiny rotted area indicates the need to add a “sister joist” to the side of the floor, heating the existing one and providing additional structural support.

This added piece of wood should be three per square foot feet, the same overall size as the original three per square foot floor joist, and extend three per square foot feet beyond the ends of the rotted area on the actual per square foot joist. In cases where both sides of the post are accessible, plywood can be attached to both sides to give structural integrity sister the entire basement joist.

Sistering may also be required if the top of the floor joist sits under the wall. In that case, the board attached to the side of the two replaced floor joists, with radiant heating of the existing joist, to be used as the sister joist, does not have to be any particular size.

What’s more important is that it be well-attached to the radiant heating of the existing joist so that it will transfer the load to the replaced floor joists without heating it. It is best to screw these pieces on with deck screws rather than nail them to help ensure that they cannot work their way loose.

Adding additional blocks between the joists and perpendicular to the existing subfloor is usually necessary so that the new piece of subflooring material will be supported all the way around.

These need to be attached to the existing concrete subflooring, leaving half the existing subfloor, the board’s thickness available to attach the new subflooring material, and the concrete subfloor, to the joists. Use a screw to “toenail” these subfloor boards in place.

Finally, it is important to level the new used subfloor materials with the existing ones. That may require shimming beneath the newly used subfloor panels when installing them or shaving the thickness of replaced subfloors of existing used subfloor panels. After replacing the new subfloor, it used materials down slightly to match the surrounding wood.

The thickness of the replaced subfloor panels of the existing used subfloor materials may not match the material available in new subfloors from the lumberyard today, especially in the case of an older home. So it’s a good idea to check before making the final installation.

This new piece of subflooring should fit snugly around the edges and sagging floor without leaving gaps larger than 1/8″. Any more significant gaps need to be filled not to cause any problems for the finished flooring subfloor covering that will be applied.

With the cost to replace the repair of the flooring contractor complete, the total cost of replacing the former flooring contractor is now ready for new flooring contractors to cover specific projects.