How To Lay Subfloor

Which way do you lay a subfloor?

Flooring experts recommend installing flooring boards perpendicular to the floor joists in a house with a plywood subfloor.

Does subfloor need to be glued?

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.

What do you put under plywood subfloor?

Plywood is only one type of underlayment. Other common types include cementboard or tile backer (used under ceramic or stone tile), foam underlayment (used under laminate and engineered wood “floating” floors), and rosin paper (used under solid hardwood flooring).

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.

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.

Do I need tongue and groove 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.

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

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

How thick should a 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.

What is the difference between subfloor and underlayment?

The subfloor is the bottom most structure of the floor. It provides a flat and stable surface and supports the actual floor. Underlayment is different from the subfloor in that it rests between the subfloor and the actual floor.

How often do you screw subfloor?

install tile unless it is screwed every 6-8″.

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.

Does plywood need expansion gap?

APA recommends a 1/8-inch space between panel edge and end joints. Plywood and oriented strand board (OSB), like all wood products, will expand or shrink slightly with changes in moisture content. If the wood structural panels are tightly butted, there is no room for expansion and buckling can occur.

What kind of screws should I use for subfloor?

Most construction experts use 3-inch steel screws for plywood subfloors. To find out which length of screw you’ll need, you first have to know how thick the flooring is. You’ll want the screw to go about an inch past the plywood into the joist or underlying layer beneath it.

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.

Does subfloor go under walls?

Wall and Floor Basics Subfloor: The subfloor is nailed to the top of the joist. Often 19/32-inch to 1 1/8-inch thick plywood or OSB, the subfloor might run continuously across the joist, or two sections of subfloor may meet on a joist. Bottom Wall Plate: The bottom wall plate is the bottom-most part of the wall.

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.

Does it matter which way you lay plywood?

Ply should always be laid with the grain running across the joists, not along the joist, to maximise the strength. Laying them length ways down a joist will cause them to crack along the grain which could end up in serious injury and or damage. The smaller the gap between joists the stronger the board will be.

What type of plywood is best for subfloor?

Cheap and strong makes CDX plywood great for use as a structural panel such as a subfloor. Remember the letter grade of plywood only has to do with cosmetics and not strength. CDX plywood is just as strong as higher grades. CDX is a type of plywood that grades C, D or X.

Do you stagger subfloor?

When you build, you always stagger. It’s what makes a pile of boards and materials into a solid structure. Stagger stagger. We did this by simply starting with a 1/2 sheet of plywood on the first row, followed by a full sheet of plywood on the next row.

How much does it cost to put in a subfloor?

Cost to Replace, Repair or Install Subfloor The average cost to replace or repair a plywood subfloor in a 306-square-foot room costs $550, or between $500 and $600. The average cost to install a new plywood subfloor is $620, or between $570 and $720.

What thickness plywood should I use 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.