How to Attach Plywood to a Subfloor
When floors are uneven or sagging, some builders use plywood and a leveling compound to reinforce the floor. Attaching plywood to an existing subfloor is one way to repair sags or cracks in the subfloor. To repair or replace a subfloor the existing outer floor covering needs to be removed. Because of this it is common to repair a subfloor when remodeling or resurfacing a floor. Does this Spark an idea?
Things You'll Need
- Utility knife
- Chalk line
- Tape measure
- Saw
- ¾-inch plywood sheet
- ½-inch plywood sheet
- Epoxy
- Sawdust
- Bucket
- Stir stick
- Paint brush
- Wood screws
- 1 1/4-inch ring-shank nails
- Level
Instructions
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1
Remove the outer flooring by cutting it with a utility knife, pulling the flooring up. Carpet or tile that has been glued down may require a crow bar or knife to create a wedge between the flooring and the subfloor. Carpet may also have nail beds around the walls that will need to be removed.
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2
Measure the area that the plywood will be attached to. Determine where the floor joists are under the subfloor. The subfloor is nailed to the floor joists. Measure the distance between the floor joists, normally 16 inches.
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3
Cut both the ¾-inch and the ½-inch plywood sheets to cover the sub floor. The common thickness of subflooring is 5/8 inch. Glue these two pieces together to create a 5/8-inch plywood sheet.
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4
Mix two parts epoxy to one part sawdust in a bucket. Mix thoroughly, but don't move too slowly. The open time for most epoxy is about an hour. This means you have one hour to mix the epoxy and saw dust, apply it to the plywood and place the other piece on top. Adding sawdust to the epoxy makes it thicker, keeping it from running out of the side of the joint, and it prevents areas without glue.
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5
Paint the top of one of the cut plywood pieces thoroughly with the epoxy mix and place the other sheet on top of the glue. Screw wood screws on the corners and along the sides to hold the boards together until the glue dries. Then remove the screws.
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6
Place the smooth side of the plywood upward and lay it on the subfloor so the corners are over the joists. Nail the plywood to the floor joists with the ring-shank nails.
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7
Check to make sure the plywood is level across the floor joists. The plywood on the floor joist may need to be slightly sanded to be level with the previous subfloor. Sand the plywood to a slight angle so the different flooring heights are not detected.
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References
Resources
- Photo Credit carpenters level image by Richard Seeney from Fotolia.com
