How to Replace the Subfloor Under a Toilet
Your subfloor is absolutely essential to the strength of your home's finished floors health. Failing subfloors can cause cracks in your tile or wood as they sag or collapse. Subfloors are generally supposed to last for the lifetime of a home; however, because of various conditions--water damage, rot or termites--it may be necessary to replace your subfloor before its time. If you are planning on replacing your subfloor, then you should know about the tools, materials and techniques available for a successful project completion. Does this Spark an idea?
Things You'll Need
- Pry bar
- Hammer
- 3-inch wood screws
- Drill or screw gun
- 3/4-inch plywood
- Jigsaw
- Tape measure
- Construction adhesive
- Caulk gun
Instructions
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Install plastic over doorways and openings to prevent dust from moving throughout your home. Use a window fan to remove any excess dust from the room in which you are working.
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Disconnect the water supply line from the toilet and remove the toilet from the floor flange. Make sure that you have drained all of the water from the toilet before you attempt to move the toilet. Have someone help you lift and transport the toilet to a safe place nearby. Make sure that the toilet is secure; it can tumble and easily break.
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3
Use a flat bar or pry bar and hammer to remove any wood, tile or carpet from the floor. If you are removing tile or hard wood, try and save as much material as possible--if you are reinstalling the same material for the finish floor.
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4
Check the floor joists of your floor after you have removed the subfloor. The floor joists should be dry and without rot or damage. If the joists are damaged, then replace them by sistering new joists onto each side of the damaged joists. Use 3-inch wood screws to secure the new joists on each side of the damaged joists. Make sure that you space the screws 4 to 6 inches apart.
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Replace the old subfloor with 3/4-inch plywood. If you suspect that the old subfloor was damaged by water or moisture, then use treated plywood. Measure the floor and transfer those marks onto the new plywood. Snap a chalkline and cut the new plywood to fit. Measure and mark the hole for the toilet flange, and cut it out using a jigsaw. Use a caulk gun and apply construction adhesive to the top of the floor joists, and lay the new plywood across the joists. Attach the plywood using 3-inch wood screws, spacing the screws 8 inches apart. Replace the finish flooring after you have completed the subfloor.
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Tips & Warnings
Always wear safety glasses and a dust mask when working on the floor.
