QA

Question: How To Subfloor

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).

What is the best way to attach subfloor?

A glue-nailed construction technique is optimal for ensuring a flat, stable floor. Use a solvent-based glue that meets ASTM D3498 performance standards; in cases where latex subfloor glue is required, careful selection is necessary due to the wide range of performance between brands.

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.

Which side of 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.

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.

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.

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.

What thickness 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.

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.

Can I put plywood over subfloor?

Plywood is made up of several layers of wood veneer glued together with adjacent layers that form a composite substance. Mobile home subfloor thickness may be of some concern, and installing plywood over this subfloor can give you a stronger base for your hardwood, laminate or carpeting.

How do you prepare a plywood subfloor?

Clean the Subfloor Step 1: Remove the Existing Flooring. Pull up the current floor. Step 2: Measure the Pieces. Check that your moisture barrier, underlayment plywood and plank fit under your door casing and door. Step 3: Clean the Subfloor. Step 4: Inspect the Moisture Level. Step 5: Secure Loose Boards.

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.

Should I seal my subfloor?

Cracks and gaps will attract moisture, so sealing them completely is an important step in making sure your floors are entirely waterproofed. Allow to dry for 24-hours.

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.

Can you put a 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 happens if you install subfloor upside down?

Upside-down Installation: Panels may be sanded on one or both sides. Installing some panels with the trademark side up may result in a slightly uneven surface. If bulk water is present on the subflooring panels, drill drainage holes or sweep the water off.

Should I glue and screw subfloor?

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 screws to use for a 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.

How far apart should subfloor screws be?

Drive the screws approximately 8 inches apart. To make the job easier for you and the drill, we suggest that you pre-drill holes before screwing the subfloor down. Use a drill bit slightly smaller than the screw and keep the hole short of the length of the screw.

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.