How many layers of plywood do you need for a subfloor?

If you are using plywood for your subfloor, you should use a minimum of one layer that is between ¾” and ⅝” thick. This thickness will suffice for most floors; however, codes will vary and a second layer is a good idea if your floor covering is going to be a heavy material like ceramic tiles or natural stone.

Do I need 2 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.

How thick should plywood be for flooring?

Some experts suggest that 15/32-inch plywood should be standard if the underlying floor joists are spaced 16 inches apart or less, but slightly thicker 3/4-inch plywood should be used for joists spaced further apart.

Can I use 1/2 inch plywood for a subfloor?

Glue is sprayed between each layer and the sheet is hot pressed. CDX plywood should be a minimum of 7/16 inch thick. The thicknesses are as follows: 7/16-, 15/32- and 1/2-inch-thick panels require joists spaced 16 inches on center; 19/32- and 5/8-inch-thick panels require joists spaced 20 inches on center.

What type of plywood should be used for subfloor?

Standard plywood can be used for subfloors, but a better material is 3/4-inch tongue-and-groove plywood subflooring. The tongue-and-groove edges interlock to resist movement along the panel edges and create an overall stiffer floor.

Installing the Subfloor

Do you nail or screw 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.

How thick is typical subfloor?

What Determines Subfloor Thickness. The minimum thickness of plywood for subflooring is about 5/8 inch.

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.

Does subfloor need to be tongue and groove?

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.

What is the best subfloor material?

Plywood. Plywood is considered the most popular material used for subflooring, it has been used since the 1950s and remains one of the top choices for contractors. Standard plywood works perfectly fine as a subflooring material, but the best option is ¾” tongue-and-groove plywood subflooring.

What size screws 3/4 plywood subfloor?

The proper steel screw sizes for securing 3/4-inch plywood to the floor joists are #8, #10 and #12 screws. The number refers to the thickness of the screw. Each is available in lengths from 1 1/4 to 3 inches. Typically, the 3-inch variety is used to secure plywood subfloors.

Which is stronger OSB or plywood?

Osb is stronger than plywood in shear. Shear values, through its thickness, are about 2 times greater than plywood. This is one of the reasons osb is used for webs of wooden I-joists. However, nail-holding ability controls performance in shear wall applications.

Can I use plywood sheathing for subfloor?

As you can see, both OSB and plywood sheathing are good options for the construction of structural sub-floors. Both are strong, durable and long-lasting.

What do you put between subfloor layers?

Adhesive will help you here, as the subfloor plywood will have voids in spots that will not hold a fastener. I use the term "underlayment" to mean a layer above the subfloor, but not the finished floor. In your case, you need the underlayment to prevent deflection along the edges of the subfloor between the joists.

Do you need plywood 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.

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.

Which way do you lay plywood subfloor?

Install plywood underlayment smooth side up. To avoid damage to the surface, install underlayment immediately before laying the finish flooring.

Why do you stagger plywood?

The end joint is where one board or plywood sheet butts up against another. In almost every situation, it's important to stagger these joints to avoid straight lines that extend in a perpendicular direction across the lengths of the boards.

How thick should subfloor be for hardwood floors?

For hardwood finish flooring, which average about 3/8-inch to 3/4-inch in thickness, 1/2-inch to 3/4-inch-thick plywood is the preferred subfloor, though there are a variety of grades designed for specific applications. Using tongue-and-groove plywood can reduce squeaks, as the sheets will seat together better.

Can I put new subfloor over old subfloor?

One of the benefits of removing the old flooring is it allows you the chance to fix any loose subflooring or squeaks by re-securing the main subfloor to the floor joists prior to installing the new flooring. With all that being said though the answer is YES you can install New Wood Flooring over the old.

What's the difference between subfloor and plywood?

OSB absorbs less moisture, but plywood dries out faster and more completely. How the subfloor materials react to water matters during both an open-air construction phase of a house as well as homeownership when a leak or flood might compromise the subfloor.

What is underneath a subfloor?

Underlayment

The underlayment material is installed below the floor covering and placed on top of a subfloor. Under the visible covering, there is a layer made of soft or foam-like materials with a thickness of between 1/4 – 1/2-inch.

How thick should a bathroom subfloor be?

Make Sure Your Subfloor is Structurally Stable

The installation guide for 1/4 inch HardieBacker recommends having wood subfloors made of 5/8 inch exterior grade plywood or OSB (oriented strand board) that is 23/32 inches thick.