QA

How Thick Should 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.

What thickness subfloor is recommended?

The recommended thickness of the plywood subfloor is governed by the spacing of the joists. 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.

Is it better to use OSB or plywood for subfloor?

The National Tile Contractors Association and the Resilient Floor Covering Institute both recommend plywood for subflooring and underlayment, because it doesn’t have the risk of swollen edges that OSB does. Plywood also has a slight advantage in stiffness, which means that subflooring panels need not be quite as thick.

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 many layers of plywood do you need for a subfloor?

Just 1 layer of 3/4 “ or 5/8” will do for most applications. If your finished floor is going to be heavy ceramic tiles, natural stone, and alike it may need to be thicker and or have more supports.

What is the minimum floor thickness?

In a typical home, the entire structure between levels can be about 12 to 14 inches thick, depending on the type of joists used and the finish materials for the floor and ceiling.

Is it better to nail or screw 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.

Can I use plywood sheathing for subfloor?

Like Sturd-I-Floor, Rated Sheathing may be plywood or OSB. When used as a subfloor, Rated Sheathing typically requires installation of an additional layer of underlayment on top of it before finish flooring can be applied. The underlayment requirements vary depending on the finish flooring.

Do you need tongue-and-groove 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.

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 best subfloor material?

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.

Should I glue second layer of subfloor?

First layer must be dry prior to laying the second layer. Place a layer of 15-lb felt on top of the subflooring prior to installing second layer. Adhesives should not be used to fasten the two layers together.

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.

What is the best plywood for subfloor?

CDX plywood is the most popular type of traditional plywood. It’s made with a rough outer layer that typically grades C, D or X. Almost all subfloor plywood is some type of CDX. There’s no reason to buy high grade finished plywood for use as a subfloor if your just going to cover it up with finished flooring.

What do you put between subfloor and underlayment?

Use building paper! Yep, put down an underlayment of 15-pound felt building paper between a wood subfloor and your hardwood planks, and you can reduce the chance of squeaky floors and control moisture.

How thick do floor joists need to be?

When choosing a joist spacing, check that your floorboards (or sheets) are strong enough to span over the width chosen. As a general rule – floorboards should be a minimum 16mm thick for joist centres up to 500mm and 19mm minimum for centres up to 600mm.

How thick should vinyl floor subfloor be?

When you install your vinyl on a wood subfloor, the top plywood should be a minimum of 1/4″ thick. For most subfloors, you will need to add an extra layer of wood. To do this, measure and cut the plywood to fit your room.

What is underneath a subfloor?

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

How thick should second floor be?

Ideally, your second-story concrete flooring should be between three and four inches thick. Like we covered above, the thickness of second-floor concrete will vary depending on your home’s structural engineering, but in general, it shouldn’t need to be more than four inches thick.