The panels should be staggered every 2 feet and spaced 1/8 inch between ends. I am about to lay 1/2" APA Underlayment rated plywood down as an underlayment over 3/4" plywood subfloor for 1/2 strand woven bamboo. The combined height is between 2-1/4″ and 5-1/4″ compared to 1″ for a DRICORE ® Subfloor R+ panel. Table 1 applies to unsanded plywood and is based on APA RATED SHEATH-ING (marked PS 1) grade. That’s 32” when plywood is sheathing for a roof (not much expected weight on it), and 16 inches as a floor (lots of expected weight on it). Filled a 20 yard dumspter. Foolishly, the tile guys wanted to mud base over just the 1/2" so the tile wasn't so much higher tha the hallway and bedroom carpets. If additional force is needed, always use a block of wood against the groove edge to minimize damage to the panel, and always allow a 1/8-inch gap between panels. 10 Posts . We’re comfortable slightly exceeding the recommended subfloor spacing. 3/4 inch pressure treated CDX goes for about $40 each where I am. Plywood is the most common type of subflooring. Subfloor plywood is extremely strong and can support most floor types including plywood and treated plywood. Steps to Install 3/4 Inch Plywood Subfloor. 9. The system is designed for use on all of the most commonly used subfloor materials—plywood, OSB, concrete and gypsum-based screed. Re: 1/2" plywood subfloor Nearly every house I framed in the 70s and early 80s was 1/2" subfloor with 5/8 particle board over in the carpet areas and 5/8" ULCX ply at the vinyl areas. If you intend to put down carpet or hardwood flooring, that won't be necessary. The floor system is not dependant upon receiving any strength from the hardwood floor to meet this requirement. What size number and length of screws should I use to screw 1/2 plywood underlayment to subfloor? The half inch (actually 15/32 inch) thick plywood that I use, adds another 73.5 lbs to the conversion. It should not be so long that it penetrates the combined thickness of the plywood underlayment and subfloor. 1-1/8 x 4 x 8 Sturd-I-Floor Tongue & Groove OSB Subfloor (Actual Size 1.069" x 47-1/2" x 95-7/8") Model Number: 1242922 Menards ® SKU: 1242922 Step 3: Secure your plywood pieces in place using 1-inch decking screws. The two layers together made up the subfloor. Step 1: Get the plywood to the right level of the house. Direction As a sub-floor, I prefer to install the plywood sideways as the finish flooring will be installed lengthwise on top of that. I'm going to install tiger wood 3/4 inch hardwood floors in my house. 1/4" plywood does not add structural integrity to a floor application and does not have the nail holding capacity. This provided a nice stiff floor and eliminated my squeak issues. Removed all original flooring down to the 1/2" subfloor. The right type of plywood for your bathroom's subfloor will vary based on the type of floor you are placing over it. I am thinking #8 length 1-1/4 inch, but I am really not sure. A conventional subfloor includes 2×4 sleepers, vapour barrier, 1″-2″ rigid insulation, 15/32″ plywood, and a lot of fastening. I have 1/2 CDX plywood subfloor. For touch-sanded grades such as C-D Plugged, C-C Plugged, UNDERLAYMENT and APA RATED STURD-I-FLOOR (marked PS 1), see Table 2. If you are using 1/4 inch plywood, and you are going through 3/4 inch subfloor, I would go with a 1-1/2 to 2 inch screw. Answer. Sturd-I-Floor® is an APA designation that is a combination subfloor-underlayment produced from OSB or plywood. Had water damage under the halfbath floor (1" mudbed). Place your plywood pieces so their joints don’t go directly over the joints of your wood subfloor. A 3/4 inch sheet of plywood weighs approximately 75 lbs. The thickness needed for subflooring depends on the type of floor that will go on top and the primary purpose for the subfloor. • Glue-down subfloor: 5/8 -inch plywood panels are glued in a staggered joint pattern directly to the slab. Leave a 1/4-inch expansion gap around walls and joints. Additionally, underlayment plywood is a middle layer that keeps moisture from reaching the surface. For hardwood, tongue-and-groove CDX plywood rated AC with a 1/2- to 3/4-inch thickness is ideal; ceramic or porcelain tile does best with 3/4-inch AC plywood; and stone should use 19/32-inch tongue-and-groove plywood. It is fastened to the subfloor and sits below the finished floor, providing a suitable base that is as smooth and flat as possible. The manual says you need 3/4 inch CDX plywood subfloor.