Instructions for Subfloor Fastening

Subfloors are installed on top of the floor joists before tile or another type of flooring is laid. Subfloors are typically made out of plywood, OSB or particleboard. All of these sheets are installed exactly the same way. A subfloor must be strong because it supports a lot of weight. A good, strong subfloor is the key to having a long lasting and safe floor in your home.

Things You'll Need

• Tape measure
• Construction adhesive
• Trowel
• 3-inch wood screws
• Drill
• Circular saw
• Safety goggles

Instructions

1. Measure the length and width of the room. Run a tape measure from wall to wall across the room and write down the measurement. Repeat the process for the width and record that measurement. Multiply the two together for the total square footage.

2. Cover the floor joists with construction adhesive beginning in the bottom corner of the room. Spread out the adhesive along the top of the joists with a trowel where the first sheet of underlayment will go. Lay down the first sheet on top of the joists in the corner of the room.

3. Run you hands over the sheet so it can adhere to the joists. Insert three-inch wood screws through the subfloor and into the joists every 12 inches throughout the sheet. Drill the screws in flush with the subfloor.

4. Apply the construction adhesive with a trowel over the joists next to the first sheet of subfloor and install the next sheet just like the first was installed. Move down the bottom wall of the room and install the subfloor. Measure and mark the last piece at the end of the first row.

5. Cut the last piece to size with a circular saw if necessary to fit. Run a circular saw over the pencil line and install this piece just like the others were installed. Line up the first piece of the second row directly over the first row and install the second row just like the first. Continue until the room is complete.

Tips & Warnings

• Always wear safety goggles when working with a circular saw.

References

• InstallFloors.org: Underlayment and Subfloors
• LivingWithMyHome.com: Building Solid Subfloors