Replacing a Rotted Bathroom Floor After a Toilet Leak

I recently discovered the floor around my toilet was soft and warped. Fearing the worst I immediately went into action. Below are the steps a friend and I took to fix the situation. I may have forgotten some details, but essentially it's 2-3 days of work for 2 people, factoring in shopping and dry time.

 

 

Some Recommended Tools & Supplies:

-Cardboard or newspaper

-Utility knife

-Hammer

-Pry bar

-Crescent wrench and/or ratchet and socket set

-Handheld circular saw or jigsaw

-Nails for flooring (when nailing down particle board a ringed/ribbed or bracket twisted galvanized nail is needed)

-Sheet of ½” particle board (or whatever the top layer board was on the floor, it may be a different thickness or different kind of board)

-Plastic sheet or garbage bag (a plastic painter’s sheet was used as a moisture barrier between floor layers in the spots that were wet)

-Wood putty/mud (not necessary if replacing the entire floor board but needed for joints between boards if replacing a portion of the floor)

-Linoleum (cut to a couple inches beyond the room size for shaping purposes)

-Glue/adhesive (used for linoleum, usually sold right next to linoleum)

-Grooved trowel (used to spread the linoleum adhesive and is sold next to the adhesive)

-Wood trim (typically sold by the inch/foot, choose something that closely matches the removed trim if possible)

-Nails for trim (shorter/skinnier smooth shafted nails work fine, only a few per trim board are needed)

-White silicone sealant (used to seal trim and toilet base)

-Metal floor joint for doorway

-Metal saw or sheers to cut floor joint

-Scissors (to cut linoleum if necessary)

-Straight edge

-Pencil

-Tape measure

-Rolling pin (to smooth linoleum)

 

 

Step 1: Pull up the toilet. Make sure to turn the water off to the toilet at the valve and to flush it first to drain it of any water. Then disconnect the water supply line at the toilet tank. Toilets are typically screwed down with nuts on both sides. A socket and ratchet or a crescent wrench will be required to loosen the nuts. Sometimes the nuts are covered by decorative plastic pieces so those must be pried off first. It’s easiest to cut away any silicone sealant along the base of the toilet prior to pulling it up as well. Toilets are heavy and may require 2 people to lift. Make sure to have some kind of mat (cardboard or newspaper work) down outside the bathroom to set it on.

 

Step 2: Take out the trim around the base of the bathroom. Typically accomplished by cutting out the sealant around the top and bottom of the trim with a utility knife and then being pried away from the wall with a pry bar or the claw end of a hammer. Note: If the trim isn’t damaged and you want to salvage it then carefully pry it away from the wall without bending it too much. It will break easily and it’s better to just replace the trim for a cleaner look when finished.

 

Step 3: Remove your linoleum, carpet, or tiles. This article will be related to linoleum specifically. Typically cutting through it with a utility knife as a start will help give a place to peel it from. It should peel off the floor with some effort.

Note: If there’s a metal joint at the door for transition between the bathroom and hallway then this will need to be pried up first.

Rotted Floor Under Linoleum

 

Step 4: Cut out the rotting section of floor. In this case the top layer of ½” particle board was completely rotted through around the toilet drain as seen in the pictures. This section of flooring was cut out with a battery powered handheld circular saw (a skillsaw or jigsaw may work) and was pried up with a pry bar. The next layer of particle board was wet but not rotted, so it was given time to dry overnight after step X was accomplished.

Floor Beneath Rotted Wood (still wet)

 

Step 5: For best results, if the remaining floor layer is wet, then it may be best to allow it to dry overnight. Shove an old towel down the drain and turn on a fan to help with ventilation.

 

Step 6: Cut new ½” particle board to the exact shape needed to fit the bathroom. In this case only half the floor was replaced so that section was measured carefully and cut using a handheld circular saw.

Note: The toilet hole is tricky to cut. Typically cutting an octagon slightly bigger than the drain hole will work.

 

Step 7: Cut the plastic sheet or garbage bag to cover the originally wet section of floor. A hole will need to be cut for the toilet drain hole as well. This will help keep the new floor dry.

 

Step 8: Place the new ½” particle board in the bathroom. Make sure it fits snuggly against the walls and against the other top layer board if only replacing a section. Place wood putty/mud at the joint between the two boards. Use a trowel to smooth it out.

Note: Some putty/mud will require 24 hours to dry, others may only be a couple hours.

Nail down the new floor board with the flooring nails. Placing a nail every 6” should do the trick. It’s best to concentrate nails along the edges and around the toilet so it doesn’t come up ever.

New Flooring (mud at joint with old flooring)

 

Step 9: Cut linoleum in the shape of the bathroom dimensions. Make sure to take exact measurements for a tight fit. Linoleum can be cut with utility knife or scissors typically. Scissors were easier to maintain a straight line.

 

Step 10: Roll up linoleum and put it in the bathroom. Typically rolling it up against one wall will work so it can be rolled as the glue is put down. Spread the linoleum adhesive using the grooved trowel. A good thin layer works. Don’t put on too thickly. Lay the adhesive along half the room and roll the linoleum over it. Make sure linoleum is snug against all walls and wipe any excess adhesive that comes out when laying the linoleum down. Spread the adhesive on the other half of the room and finish rolling out the linoleum.

Note: It may help after laying the linoleum down to use a rolling pin to smooth it out.

Linoleum Down (no trim yet)

 

Step 11: Cut and install the new metal joint in the doorway between the bathroom and hallway. It was a cleaner cut to use a metal saw than sheers. The joints come with their own nails to hammer them down into the flooring.

 

Step 12: Cut the trim needed for the base of the room. Most trim has 45 degree angles in the corners so it’s important to measure the exact lengths you need at the longest part of that wall and then cut a 45 degree angle at that point. (This step is not needed if reusing old trim)

Note: Cutting 45 degree angles can be tricky. Most saws come with angled settings so it’s recommended to use a skillsaw or table saw with an angle adjustment.

 

Step 13: Install the trim. Place them in one at a time. Make sure the angles fit correctly against each other.  Nail them in using the smaller nails. Typically 1 nail every foot is all that’s needed. Make sure to drive the nails into the wood so they can’t be seen.

Note: You may consider covering the nails with paint or the silicone sealant to hide them if they aren’t concealed.

 

Step 14: Use white silicone sealant along the tops, bottoms, and corners of the trim. Use a finger or popsicle stick to smooth it out. No excess sealant is necessary, it just needs to get into the grooves.

 

Step 15: Replace the toilet wax ring. In this case a double thick wax ring with flange was bought. This ensures a good seal when mating with the toilet.

 

Step 16: Re-install the toilet. This is a 2 person job. It will require lining up the toilet with the mounting studs. Once the toilet is down, ensure it is sitting well on the wax ring. Any gap at all will result in future leaks. It may be necessary to tilt the toilet or picking it back up to see if the wax ring is indented. Fasten down the nuts on the studs so the toilet doesn’t rock. Hook up the supply hose back to the toilet tank and turn back on the water valve.

 

Step 17: Use the silicone sealant around the base of the toilet for a good seal. If wanted leave an unsealed patch in the back so that any future drain leaks can be detected more easily.

 

Step 18: Flush the toilet and hope it doesn’t leak. If done properly it should be good to go. It is best to wait 24 hours prior to using the bathroom so the silicone sealant and linoleum adhesive have time to dry.

Finished Product