The answer: Glue. Although using a subfloor adhesive (or subfloor glue) is not required by code, it is a standard practice that can help prevent floor squeaks by reducing the chance for movement at the panel-to-joist connection. A quality subfloor adhesive will also increase the overall stiffness of the floor.

Does plywood need to be glued?

Some types of plywood underlayment require specific types of glues, while other should only be screwed down. Some flooring systems also recommend not gluing down the underlayment, which should always be taken into consideration before you start installing the plywood.

Can you put plywood over subfloor?

Install a layer of at least ½” or preferably 5/8” ply over the existing planks. This is particularly important if your old sub floor has lumps and bumps in it. If you don't respect this thickness of ply, then you're highly likely to see rises and falls in your new flooring.

Do you glue or nail subfloor?

Ideally, nail down your subfloor using corrosion-resistant nails that will securely hold it in place and last a long time. Screws are a great alternative that you can easily remove, but they are not as sturdy. Screws are superior in terms of reducing floor squeaks, but the installation is slower.

Should you glue down plywood underlayment?

No, you should not glue down your underlayment. Underlayment is is a floating material, the same as your laminate flooring. In most cases, you should not glue or nail your underlayment down. You should always check with the installation instructions of the underlayment for proper installation instructions first.

Putting Down Plywood Subflooring with Adhesive

Is it OK to nail subfloor?

Using code-approved screws rather than nails is the best option for avoiding movement. If using nails for subfloor installation, stick with ring-shank nails; smooth nails may withdraw easier, leading to squeaks.

Do I need two layers of subfloor?

That's the usual approach. Almost no one puts down double-thick subfloor in residential applications (for cost and handling reasons), and both layers need to be fastened to joists. Only thin underlayment can be fastened just to the subfloor.

What do you put on top of subfloor?

Plywood underlayment is typically needed when a floor material must have a very smooth, flat surface. For example, if you install resilient tiles or sheet flooring over a subfloor, any bumps, dips, or voids in the subfloor may be evident in the finished flooring.

Is it better to use OSB or plywood for subfloor?

OSB has a lower resale value than plywood due to its lower strength. For this reason, few homeowners prefer OSB in their homes. Apart from costs, plywood is superior in all the other areas, such as the strength of the structure. For this reason, it's a superior material for use on the subfloor.

Do you have to use subfloor adhesive?

Although using a subfloor adhesive (or subfloor glue) is not required by code, it is a standard practice that can help prevent floor squeaks by reducing the chance for movement at the panel-to-joist connection. A quality subfloor adhesive will also increase the overall stiffness of the floor.

Do you have to use tongue and groove plywood for subfloor?

For subflooring, you use tongue and groove plywood. The tongue and groove are only along the 8 foot edges. On the four foot edges, your seams will fall on joist tops, so no need for tongue and groove. But to start off, we will need to remove the tongue so the plywood is tight with the exterior ICF walls.

Should tongue and groove be glued?

The recommended glue for floating installation is Tongue and Groove engineered flooring glue. Glue placement is very important. The glue must be placed along the topside of the groove the full length of the grooved side and end.

Can I use screws for plywood underlayment?

Rather than nails, screws are best to use for subfloors — these fasteners are convenient, easy to remove and capable of providing torque that nails lack. Because of their structure, screws can penetrate plywood more easily and improve the connection, whereas nails can weaken the plywood.

What size plywood is best for subfloor?

The spacing of the joists governs the recommended thickness of the plywood subfloor. Some experts suggest that 15/32-inch plywood should be standard if the underlying floor joists are spaced 16 inches apart or less, but you should use slightly thicker 3/4-inch plywood for joists spaced further apart.

Do I need moisture barrier on wood subfloor?

Do I need a vapor barrier for hardwood floors?" The answer is YES! Moisture can destroy hardwood flooring. It causes cupping, warping, and even mildew if not treated. You must install a moisture barrier to protect your flooring from water wicking up from below.

Should I put tar paper under subfloor?

Foam, felt and rubber are the best choices for laminate underlayment. Do not select tar paper to go under laminate or vinyl flooring, because the odor can penetrate the air and the fumes can be toxic, according to Uooz.

What do you use to fill gaps in plywood subfloor?

Using fillers is perfect to fill gaps in plywood subfloor or OSB subfloors, but it's certainly not the most aesthetic way to fix your floor. If you wish for something as efficient, but more natural and permanent, you can use other materials such as wood strips, wood shims, or ropes as a subfloor gap filler.

Do you need to fill gaps in subfloor?

Fill Plywood Subfloor Gaps

You don't have any control over a subfloor that you just uncovered by removing carpeting or some other flooring, however, and it's important to fill existing gaps to guarantee thermal and moisture isolation and protect your new flooring.

Should plywood underlayment be screwed to joists?

It is nailed or screwed to the joists to secure it completely. Adding fasteners to this layer before laying underlayment helps stabilize and quiet an old floor. Drive screws or nails through the subfloor and into the joists. These screws or nails should go in between the existing fasteners for reinforcement.

How thick should my subfloor be?

The minimum thickness of plywood for subflooring is about 5/8 inch. Since it does not hold fasteners as well as plywood, OSB must be a little thicker, or at least 23/32 inch. There are several factors that determine what subfloor thickness is optimal for added benefits like insulation.

Does plywood need an expansion gap?

Unlike laminate floors which float over an existing floor and have expansion gaps, plywood is usually screwed or nailed into position and expansion gaps are not necessary. You should fit the plywood sheets tight together , but always leave a 10mm expansion gap at the perimeter.

Are screws or nails better for subfloor?

Screws are preferred over nails for subfloor and underlayment installations as they provide strong and tight connections that help prevent the floor from squeaking. Before starting your next subfloor or underlayment installation, make sure you have the right subfloor screw gun for the job.

Does plywood subfloor need to acclimate?

Any uneven subfloor joints should be sanded so the joints are even. Acclimate the plywood underlayment panels 24 hours in the area the panels will be installed and 48 hours in extreme conditions.