Is 3/4 subfloor enough?

Author: Miss Ettie Mills IV  |  Last update: Saturday, May 31, 2025

Deciding on the appropriate thickness depends on the span and expected load on the subfloor. Generally, 3/4-inch plywood is suitable for most residential applications, while 5/8-inch plywood may be sufficient for shorter spans or lighter loads.

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.

Can I use 3/4 inch plywood for subfloor?

The best plywood for subfloor depends on the specific requirements of the space and the expected exposure to moisture. For general residential use, 3/4 inch CDX plywood (3/4 plywood) with tongue and groove edges is a reliable choice.

Is 3/4 plywood strong enough to stand on?

On average, 3/4-inch plywood can support a distributed load of approximately 50-75 pounds per square foot (PSF) when properly installed and supported.

How far can 3/4 subfloor span?

Maximum span 24 inches where 3/4-inch wood finish flooring is installed at right angles to joists.

Subfloor VS. Underlayment Explained

How far can 3 4 plywood span without sagging?

3/4" plywood can span up to about 36" without support, but at 32" wide, the length of 76" makes it prone to sagging over time without additional support. Adding a center support will help prevent sagging and ensure the shelf holds up properly.

How much weight can my subfloor hold?

Safety factor is a measurement with which your floor was designed to support loads without collapsing. Most homes have a safety factor of 40 PSF (pounds per square foot).

What thickness plywood is safe to walk on?

Recommended Thickness Ranges for Plywood Flooring

A 1/2-inch (12mm) to 5/8-inch (15mm) thickness range is commonly used to ensure proper stability and prevent flexing.

Is plywood strong enough to hold a TV?

The load-bearing capacity of plywood is limited, especially when compared to walls with studs. Mounting a heavy TV on plywood can cause the wall to bend or break, posing a safety risk. The holding power of fasteners in plywood is not as strong as in solid wood or studs.

How thick should plywood be to sleep on?

Plywood comes in different thicknesses, ranging from 1/8 inch to 3/4 inch or more. The most common thicknesses used under a mattress are 3/8 inch, 1/2 inch, and 3/4 inch.

Do you leave a gap between plywood subfloor?

Don't beat the sheets together tightly, you must leave 1/8” gap at all sides of the panels to allow for swelling. The sledge makes it easy to “persuade” the sheets together, but don't hit it hard. Be very particular about that 1/8” gap.

Do you need 2 layers of plywood for subfloor?

For added strength and stability, a double-layer subfloor is often recommended. In this configuration, two layers of plywood are installed, with the top layer offset from the seams of the bottom layer. By staggering the seams, the subfloor's overall strength is enhanced, reducing the risk of deflection or squeaks.

Do I need underlayment over subfloor?

Flooring underlayment is not always necessary, primarily when you are using a flooring that has its own underlayment padding such as . But underlayment can help with a wide variety of issues, such as sound control in a cement floor application or cold floors in a basement for example.

What is the code for subfloor thickness?

The code requires 1 1/4" floor thickness (overall) unless it is tongue and groove plywood in which case 3/4" is adequate. Will 1/4” plywood over 1x10 plank subfloor be thick enough t ...

Does subfloor need to be perfectly level?

No subfloor is perfectly level, but any signs of unevenness and high or low spots must be remedied. Please follow these requirements: Subfloor unevenness cannot be greater than 3/16 of an inch over a 10-foot span or 1/8 inch over a 6-foot span.

Is 3/4 subfloor enough for tile?

The combination of double-layer 3/4–inch plywood and a membrane can be used for all ceramic tiles and many stone tiles.

Can I mount a TV to 3/4 plywood?

For mounting a 65" TV, it's essential to screw into standard 2x4 studs (which are 1.5 inches thick). If using plywood as backing, at least ¾" thick plywood is recommended to ensure strength. Make sure the screws penetrate securely into the studs for optimal support.

Is 3/4 inch plywood strong?

The 3/4-inch plywood is generally considered thicker and potentially more durable, making it suitable for heavier loads or applications where strength is paramount.

How thick does plywood need to be to support weight?

Typically, 3/4 inch plywood is a good choice for sturdy shelves that need to support heavy items. For lighter loads or decorative shelves, thinner plywood (like 1/2 inch or 5/8 inch) may suffice. Always consider the load-bearing requirements and span distance between supports when selecting plywood for shelving.

Is 3/4 plywood good 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.

How much weight can 3/4 plywood hold vertically?

How Much Weight Can 3/4 Plywood Hold? 3/4 inch plywood can hold up to 50 pounds per square foot.

Is OSB better than plywood for subfloor?

Both plywood and OSB are effective choices for your subfloor needs, but OSB may be a better option for a garage than plywood. Plywood is a better option for projects that require a lot of cutting and molding, while OSB is a good option for those who need to cover areas where moisture exposure may be an issue.

How thick is subfloor normally?

However, a general rule of thumb is to have a subfloor that is at least ½ inch (12.7mm) thick. This will help ensure that the floor is stable and won't flex underfoot, which can cause the LVF to become damaged over time.

Can I put a 300 pound safe upstairs?

The short answer is yes. It's your choice where your safe is installed. Our delivery team can and has installed safes on the second story of homes and office buildings.

How much gap between subfloor boards?

To avoid buckling, subfloor panels should be spaced with a 1/8-inch gap at all edges and ends to provide room for naturally occurring expansion. Tongue-and-groove edges on many premium floor panels, such as Weyerhaeuser's Edge Gold® OSB panels, are designed to self-gap.

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