1/8″ plywood, in my opinion is not sufficient; unless it was set down on flat surface with troweled adhesive and stapled 4″ o.c. I would recommend 1/4″ min – which can be found at most flooring supply stores – specially formulated for flooring; i.e., all voids filled in the plys and water resistant glue.

How thick should underlayment plywood be?

about 1/4 inch thick





Most plywood underlayment is about 1/4 inch thick and has square edges and a smooth, knot-free top face. It typically comes in 4 x 8-foot sheets.

What type of plywood should be used for underlayment?

Poplar or Birch Plywood with a fully sanded face and exterior glue. Lauan Plywood, when used as an underlayment, should be Type 1 (Exterior). The best grade is BB and the next best is CC, while OVL (overlay grade) is the minimum acceptable face grade. There is a wide variety of quality and species classed as lauan.

How thick should underlayment be?

Underlayment: Just under the visible floor covering is a layer of some kind of material, usually only about 1/4- or 1/2-inch thick. Its purpose is to provide a smooth, flat surface for the floor covering. It can be made of many different materials, chosen depending on the needs of the floor covering.

Can you use plywood instead of underlayment?

Plywood Suited for Underlayment





Recommendations aside, plywood is one of the most versatile underlayments because it will give you that nice, smooth surface needed for a flawless vinyl or carpet installation, and it works under most other products too.

What is the thinnest subfloor?

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 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.

How thick should underlayment be for vinyl flooring?

1mm to 1.5mm thick



Most vinyl underlayments are 1mm to 1.5mm thick. When dealing with a click lock vinyl of 4mm or thicker, an underlayment has several benefits: It can help smooth over minor subfloor imperfections. It will add extra cushion to the floor, creating a softer feel under foot.

How thick should roofing plywood be?

Most Common Thickness

The most common rafter spacing is 24 inches, and 5/8-inch plywood is recommended for that. It will support roof loads for most situations and is the standard for most roof applications. Roofs with very heavy loads may require 3/4-inch thickness.

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.

Can sanded plywood be used for subfloor?

Plywood Grade

However these letter grades don’t represent structural properties. They’re all about cosmetics. Higher grade plywood is made of better looking wood that’s sanded and sometimes stain grade. Premium grade plywood is most commonly used for making furniture or cabinetry and not as a subfloor material.

What kind of plywood do you use for vinyl flooring?

Rigid Underlayment



Plywood is often the most commonly used type of underlayment in vinyl plank flooring installation. Sheets of 4×8 foot plywood, usually ¼ to ½ inch thick tend to be an excellent flooring underlayment for many subfloors including wood, tile, and linoleum.

How thick should plywood be for vinyl flooring?

1/4″ thick

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.

How thick should laminate underlayment be?

We would recommend an underlay of 3 – 5mm for laminate flooring. It should be at least 3mm thick to provide comfort and ground levelling properties. But, it should be no more than 5mm thick. If it’s any thicker, you could experience problems with the laminate’s locking system.

Do you need a moisture barrier under vinyl plank flooring on plywood?



There’s no need for a moisture barrier underlayment on plywood. It’s more important that the underlayment dampens sounds and feels comfortable. An underlayment that offers more cushioning is Armstrong® Flooring Quiet Comfort™.

What type of underlayment do you use for vinyl plank flooring?

The rule of thumb is any vinyl over 4mm can have a vinyl specific underlayment. With thinner vinyl flooring construction, adding a foam underlayment can effect the locking system strength. Vinyl floors under 4mm should be installed right over the subfloor.

Do you need vapor barrier on plywood subfloor?

Manufacturers Require a Vapor Barrier

Your plywood subfloor may look dry, but after you install the flooring, moisture can migrate up through the subfloor and penetrate the flooring, and the results are usually disastrous.

Do you need plastic under underlayment?

Placing a sheet of plastic between the subfloor and the flooring will keep your flooring from getting damaged. If there is no barrier, once the plywood subfloor starts to develop moisture, the moisture can create mold, which can destroy your flooring. If you have carpet, it can cause mold and mildew to grow through it.

What can I use instead of underlayment?

If your laminate flooring comes with attached foam underlayment, or if you bought standard foam underlayment, you can use a vapor block film to prevent moisture and protect your flooring investment.

Does plywood act as a vapor barrier?

1) Exterior plywood sheathing is a moderately effective vapor retarder with a perm rating of less than 1.0 as long is it is kept dry and the relative humidity is low. When plywood is wet or relative humidity is high, its permeance will range from above 1 to as high as 10.