Replacing rotten subfloor under toilet. How thick is the floor, typically?
It was built in ‘78 in New England. I’m tackling this project myself ’cause I haven’t got the $$ to pay somebody to do it for me.
I already pulled the toilet up and most of the vinyl. It’s probably about 1 1/2 cu.ft. of the floor that’s water damaged. There are drip marks in the kitchen below it, but you can’t see through.
I read in another forum that the floor is probably 3/8" thick, but that doesn’t sound right to me. The suggestion was to use a circular saw and take off a bit at a time; all the rotten stuff to the nearest joist. I understand the bit about checking the floor joists for damage and sistering joists as necessary. I’m more concerned with ripping the wet stuff up. Any suggestions? All I own is a jig saw so I’ll probably rent – or buy – a circular saw. I’m more concerned with the thickness of the sub-floor ’cause I don’t want to cut too deep.
Also, how far apart are the joists supposed to be?
One Response
wvparanormal
13 Nov 2009
Let us know your thoughts!
You must be logged in to post a comment.
Floor joists are typically 24" on center. Plywood sub flooring is typically 3/4".
You need a circular saw for the job. You can buy one at any home center for around $40. If a blade comes with the saw, the blade that comes with the saw should be good enough for this job. If no blade comes with the saw, buy a carbide tipped combination blade. Ordinarily to cut plywood you would use a fine tooth plywood blade, but that is NOT the blade to use here. You will also need a tool called a cat’s paw and a hammer. The cat’s paw is a tool for pulling nails. The guy at Lowes or Home Depot will know exactly what you’re talking about.
Pull up the vinyl and find where the plywood is nailed to a joist. Pull the nails out of the plywood using the cat’s paw and hammer. Mark a line along the nail holes. Go 24" and find the next row of nails and do the same thing. Mark a line at a 90 degree angle past the edge of the damaged plywood.( make sure your cross cut is in good wood).You probably will not be able to remove the toilet flange, so you will have to use your jig saw to cut as close to it as you can and break the plywood away from it. Now you will need 4 pieces of 2×4 or 2×6 that are about 22-1/2 " long.( measure the distance between the joists). You want to toe nail ( nail at an angle) one piece between the joists at the end of your cut out, flush with the top of the joist. Make sure it is slightly under the original plywood as this will support the joint where the old plywood and new plywood meet. Do the same thing at the other end. Take the other two pieces and nail them in on both sides of the sewer pipe under the toilet flange. Cut out your new piece of plywood and you will have to measure from the end of the cut out to the center of the sewer pipe hole and cut the new piece in two at that point. Mark the hole for the pipe and cut it out with your jig saw. Slide one piece under the flange and let it drop into place. Do the same with the other piece and then use drywall screws to secure them to the joists and screw the flange to the new wood. ( You are using screws so that you do not knock the cieling loose under it by hammering nails, as a matter of fact, you should use 2-1/2" drywall screws to attach the support pieces as well)
That should have you fixed.