How to Replace the Wood on Top of Floor Joists

Joists form the skeleton of you home.

A floor is constructed with interlocking layers of materials to form a strong surface to stand, store your belongings and conduct the activities of everyday life. The first layer of the floor, the layer that forms the very structure, is comprised of floor joists. The next layer is the sub-flooring. This wood rests on top of the joists to give you a platform on which to build the rest of the floor. Replacing the sub-flooring in your home may eventually become necessary due to impact, water damage or simply age.

Things You'll Need

• Framing hammer
• Pry bar with nail puller
• Broom
• ¾-inch sub-flooring grade plywood
• Tape measure
• Pencil T square, 4 feet long
• Circular saw
• Drill with Phillips bit
• 3-inch galvanized deck screws
• Caulk gun with construction adhesive
• Work gloves
• Safety boots
• Safety glasses

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Instructions

1. Remove the old sub-flooring. Pry up the existing plywood with your pry bar and hammer. Remove any screws with your drill. Discard the old materials and sweep the loose debris off of the joists with your broom.

2. Measure the joists. The plywood will lie so that the long axis covers as many joists as possible. Both ends of the plywood will end in the middle of a joist. Mark the plywood to be installed with your pencil. Extend the marks across your plywood using your square to ensure a straight line. Cut your lines with the circular saw.

3. Apply a line of construction adhesive to the tops of the joists to be covered with your plywood. Lay the plywood on top of the joists. Maneuver the plywood so that the edges of the ends rest in the center of a joist. Run screws through the plywood and into the joists below. Place a screw every 8 inches along each joist under the plywood.

Tips & Warnings

• Working with hand tools and power tools requires the use of safety equipment such as work gloves, safety glasses and safety boots.

• Removing and replacing joists involves working at heights. Always be aware of your foot placement, location on the site and balance. Work with a helper, or helpers, in any job done at heights. Always work slowly and methodically, keeping safety ahead of your mind in front of production.

References

• The Tile Doctor: Repair Subfloor Water Damage