Glue with PL premium to joists & screw the ply into the joists. 1/2 & 3/8 ply is not designed for subfloor use.
For subflooring, 3/4-inch plywood is generally the better choice compared to 5/8 plywood.
Many local building codes only require 3/8” plywood for roofing.
CDX plywood is the most common plywood used for subflooring. It is usually more affordable because it is rougher and has more imperfections than other types of plywood. However, since subflooring is almost always covered and rarely visible, the way it looks should not matter.
Non-structural plywood has no structural or load bearing properties, however it can also be used as subfloor underlayment for tile floors or other non-load bearing applications like wainscoting or chair rail. Non-structural plywood comes in sheets often solid core plywood.
On the other hand, non-structural grade plywood is not recommended for external or high load-bearing applications due to its weaker bond strength levels. Aesthetics are also an important factor when choosing between these two types of plywood.
C-grade plywood should be used when appearance is not important, such as for subfloors or garages. D-grade is also unsanded with defects that have not been repaired and knot holes up to 2 1/2 inches across, discoloration and sanding defects.
Just get the proper 3/4 in plywood. Glue with PL premium to joists & screw the ply into the joists. 1/2 & 3/8 ply is not designed for subfloor use.
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 ...
Rather than nails, screws are best to use for subfloors — these fasteners are convenient, easy to remove and capable of providing torque that nails lack. Because of their structure, screws can penetrate plywood more easily and improve the connection, whereas nails can weaken the plywood.
plywood has been made in metric thicknesses since 1978. However, some, but not all thicknesses are s ll available in approximate Imperial sizes: 6mm (1/4″), 9.5mm (3/8″), 12.5mm (1/2″), 15.5mm (5/8″), 19mm (3/4″), and 25.5mm (1″).
Strength. OSB and plywood are very similar in terms of strength, but plywood is stiffer than OSB by a factor of approximately 10%. This doesn't cause much of a difference, but nails are screws are more likely to remain in place over time than they are in OSB.
Sheathing Thickness
You may see 3/8-inch plywood installed as roof sheathing and, although it may feel inadequate compared to 1/2-inch plywood installed on rafters spaced 24 inches on center, 3/8-inch plywood was, at one time, considered acceptable in some jurisdictions.
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.
Plywood is the most popular material used for subflooring because it's strong and stiff. It comes in different thicknesses, with the thicker options being the best choice for a subfloor. The tongue-and-groove plywood is the best option because it has interlocking edges that help prevent movement.
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.
Thicknesses for products used for subfloors are generally 23/32 inch (just under 3/4 inch), but thicker sheets are available where building codes call for them.
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.
Recommended Thickness Ranges for Plywood Flooring
For underlayment purposes, such as preparing a smooth surface for vinyl or carpet installation, the typical recommended thickness ranges from 1/4-inch (6mm) to 1/2-inch (12mm) plywood.
Standard plywood works perfectly fine as a subflooring material, but the best option is ¾” tongue-and-groove plywood subflooring. This system has interlocking tongue-and-groove edges, which help prevent movement along the panel edges, resulting in a stiffer floor.
So, for example, a plywood sheet with a thickness of 3/8 inch really has a thickness of 11/32 inch. Standard thicknesses for plywood panels are 1 ¼, 1 1/8, ¾, 5/8, ½, 3/8, ¼, and 1/8 inches. This makes corresponding actual thicknesses of 1 ¼, 1 1/8, 23/32, 19/32, 15/32, 11/32, 1/4, and ⅛, respectively.
Improperly spaced and placed subfloor panels can cause performance issues and lead to various structural failures, such as raised joints or buckling. While installing panels too tightly or without any gaps won't allow the material to expand and contract, leaving too much gap can cause excessive movement and noises.
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.
Rubber is one of the best choices for underlayment because it is super versatile. It protects your floor from mold and mildew and protects your ears from hollow sounding floors. In fact, it is one of the most sound absorbing and insulating underlayments out there.
You can select from a variety of PAMFast screws, ranging from 1 1÷4” to 3,” which gives you plenty of options to meet the required depths for your project. There are various options for wood-to-wood applications, as well as a screw for high-density wood attached to lumber.