Sawing the Subfloor

Nails, Screws and Fasteners

• The subfloor is nailed or screwed to the floor joists. Finding and removing the nails or screws is not only a safety precaution before attempting to saw out your subfloor, but it can give you an idea where your floor joists are. The nails or screws will run along the floor joists in a straight line.

Pipes and Wires

• Before attempting to cut out your subfloor, you must ensure there are no pipes or wires running under the subfloor between the floor joists. If you are working on the first floor, this will necessitate gaining access to the basement or crawl space and checking the area for anything that could be damaged by the saw. Wires and pipes should be relocated or rerouted to avoid the area to be worked on.

Floor Joists

• When cutting out the subfloor, you must avoid damaging your floor joists. Circular saws are useful because if you know the thickness of your subfloor, you can set the depth of the blade for just short of that thickness. When making cuts that run parallel to the joists, always cut over the joist centerline. This allows you to secure your new subfloor to the joist. After cutting out the section of subfloor you want to remove, use a chisel to break the piece free. Cut the section into smaller pieces to make removal easier.

Tool Choice

• Cutting the subfloor is a delicate process. The more precise of a saw you can use, the better chance you have of avoiding obstacles and joists. A small rotary tool can be used to cut out small pieces and work around molding or transitions. A jigsaw with a depth setting is also useful for tight spots and will give you more tactile feedback, if you are hitting a joist or obstruction, than a circular saw. Pull up the cut subfloor using a crowbar or prybar, using the floor joists for leverage.