Do I need 2 layers of subfloor?

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 subfloor should you have?

The four layers that make up the wood floor system consist of; the Joists, Subfloor, Underlayment, and Floor Covering.

What is the minimum subfloor thickness?

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.

Can you lay subfloor over subfloor?

Things to take into account when laying ply over plank subfloors: Take time to make sure your existing planks are well secured in place. Repair any broken planks. Install a layer of at least ½” or preferably 5/8” ply over the existing planks.

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.

Subfloor VS. Underlayment Explained

What goes on top of subfloor?

Underlayment: Some types of flooring can be installed directly on top of the subfloor, such as vinyl flooring. Other types need a middle layer, called underlayment, such as laminate,carpet and tile.

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.

Should I glue second layer of subfloor?

Adhesives should not be used to fasten the two layers together. Install second layer on top of the first layer inside of the wall studs. A minimum ¼” gap is required between the second layer and wall perimeter.

What do you put between subfloor layers?

Felt paper (15lb) or similar material should be used as a buffer between subfloor and underlayment. The underlayment (in your case the second tier of OSB) should be offset from the subfloor.

Should I remove old subfloor?

“Adequately protected from moisture, most subfloor materials can be expected to last for the lifespan of the home.” However, if the subfloor is consistently exposed to moisture, you may need to replace it after 20 to 30 years or sooner.

Is 3/4 plywood OK 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.

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.

Can you use half inch plywood for flooring?

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.

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.

Do you need a 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.

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.

Do you need vapor barrier between subfloor layers?

Vapor Barrier Blocks All Moisture Issues

It just depends on how much moisture it emits. Concrete is porous in nature and will soak up any moisture that is in the ground and show up on the top of your concrete. So we recommend vapor barrier for all flooring installation that have a concrete subfloor.

Should you nail or screw down 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 I glue subfloor to joists?

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.

Should plywood underlayment be glued to subfloor?

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.

How often do you screw subfloor?

Generally, nails (6d ring or screw shank, or 8d common) should be spaced 6 inches on center along supported panel edges and 12 inches on center on the panels' interior supports, or as specified on the construction drawings.

Can I use regular plywood for subfloor?

Plywood has been a standard subfloor material since the 1950s and remains the preferred subflooring for many builders. Standard plywood can be used for subfloors, but a better material is 3/4-inch tongue-and-groove plywood subflooring.

Which side of OSB subfloor goes up?

When installing sub-flooring, you'll want the rough side facing up as well for traction when working. This is especially true when you have OSB that has been treated with a sealant or moisture barrier.

What is the difference between subfloor and underlayment?

Basically, subfloors are a structural part of your home that provide strength and rigidity to your home's flooring. Underlays, on the other hand, protect your floor covering from moisture, help soundproof your floor, and offer cushioning and comfort underfoot.