I had a tenant skip out on me and he left me with a toilet that has been dripping water for some time (of course he never called me about it) and it has saturated/rotted-out the plywood sub-floor. Today, the toilet, pedestal sink and sheet vinyl were removed. On Tuesday, I will be cutting out a 3x4 section of 3/4 inch plywood that supports the toilet. The other half of the bathroom sub-floor seems to be okay.

I will use a circular saw to make a 3/4 inch cut into the plywood near the door going straight across but I will have to stop once I get near the fiber glass bath tub. About 30 inches of my damaged sub-floor runs underneath the fiberglass bath tub.

My question is : what is the best cutting tool to use to cut the plywood that runs along the bottom edge of the bath-tub and also near the adjacent walls also? I want the cut to be as flush (no pun intended) as possible.

The cutting tools that I own are : Reciprocating (saw-zaw), Jig-Saw, Oscillating cutting tool, Angle grinder,...and a Chainsaw.

Ryobi plus 1 with oscillating head. Dremil also makes it. I think they call it the multi max.

Thanks NE,

I have seen the half-moon cutting blades at Lowes but have never needed one. I guess I do now. I will get one tomorrow.

Mikita multi tool , the one that doesn’t need a tool to change the blade. Holds blade very securely, doesn’t work loose.

Dont know which one you have. With oscillating tools a good blade is just as important as the tool.

For a large job like that I would use a carbide wood cutting blade. Stays sharper longer so cuts faster. Bosch makes a good one.

I would use the recip saw with a 12 inch blade along the wall. It will be almost as quick as the chainsaw. Lay the blade as close to the floor as possible and against the wall, the hook on the end of the blade is your friend, it will be doing most of the cutting.

I'd use the Sawzall with an extra stiff demo blade.

Don't forget to add bracing before the new plywood.

Roy, I'm sure you already know this, but make sure you don't cut any of the joists with that Sawzall.

Gevans,

Thanks for your input. I will try that extra stiff Saw-Zaw blade you mentioned. I love my green Hitachi Saw-Zaw but keeping it under control (no bounce) in tight spaces is sometimes a challenge.

FYI: My oscillating tool is the Rockwell (Shop Series) model and it costs around $50.00 at Lowes. What brand of Oscillating tool do you all recommend?

NE,

Ryobi is the cheaper, maybe cheapest, line you can buy except Harbor Freight garbage.

If one breaks, I just replace it. I think the oscillating tool is $69. Plus it's cordless and the batteries work with all the other cordless tools which is the best part for me. I have tons of them and if I see a new one come out, I'll buy it.

NE,

One final question before I leave here and go get dirty.

When the time comes for new plywood, how would you cut the hole for the 4 inch wide cast iron drain pipe? I have a 4.5 inch hole saw but my measurements have to be exact. Or I could use the jig-saw and just cut a square opening.

Roy, I personally find that Fein's German made blades are the absolute best blades available for oscillating saws. The Bosh blades found in most big box & local hardware stores are also a decent blade. However I find that both of them even they are on sale are too expensive for most LL's use.

For those of you who don't have a zippy saw, I find the $20.00 single speed one from Harbor Freight works just fine. They routinely have them on sale for Less than $15.00. The HF blades that come with the saws are not very good. Other than the blades that come in the kit, I would never waste any money on buying any replacement HF blades.

I buy my zippy blades on line in 50 packs for $.75 - $1.50 a blade. The last ones I ordered were from Multiblades Direct. I find these are much better than the Harbor Freight blades & almost as good as the Fein & Bosch blades. Since most oscillating saws have slightly different blade holders, you need to be sure to tell them what brand of oscillating saw you have.

Now to the project on hand. I usually use a 2"-4" hole saw to carefully make a hole thru both the underlayment & subfloor. This allows me to locate the framing as well as wiring & piping. I use a circular saw to remove most of the flooring. This allows me to easily control the depth of my cut & get within 1 1/2" of the walls. To get the last 1 1/2" I use a sawzall in areas where I'm not too concerned about damaging the wall. In other areas like next to the tub, I use a piece of zinc (not aluminum) flashing to help protect the finished surface while I cut with a zippy saw. IMO it's better to spend a little more time making a controlled cut than to spend a lot more time replacing a damaged tub.

Of course if you were willing to invest in another tool you could get a flush cutting toe kick saw to do this.

Steve (MA)

Describe your 'zippy saw',..I have never heard of it. With your zippy saw, does the cutting blade spin or oscillate or what? I have to google zippy saw.

Thanks for those great cutting tips. I still have the 1/4 round next to the tub and I will leave that in place when I get ready to cut close to the tub.

My 75 year old handyman just called and says that if it rains today, he will have to stop his roofing job and then he can come over and give me a hand. That is IF it rains today which is about 50/50.

I recently did a similar repair to Roy's..

The wood next to the tub was saturated with water and a chisel was adequate to remove most wood within couple minutes.. I won't sweat the last quarter inch of the wood.. Nobody steps that close to it.. leave a small gap and fill some cement if you are perfectionist.

Roy,

Toe kick saw, aka flush cut saw is a new one for me. I think I need a new tool! That looks like a handy saw. And $1.00 blades from Multiblades Direct? Awesome!

For marking the hole for the toilet drain pipe, I use lipstick. I put a long, long strip of duct tape on the underside or the plywood, with ends sticking up to create handles for pulling the plywood back up. Then I slather generous amount of bright red lipstick around the edges of the toilet pipe (dollar stores have cheap lipstick. Brightest red is best. ) lower plywood in place, and stand on the plywood, rocking the board to catch all of that lipstick. Now, getting the plywood back up is when those duct tape handles come into play. Again, it’s one lone continuous piece, going side to side, or end to end. If you try to save on duct tape and use smaller pieces, it can pull off.

Then the hole can be cut with jig saw. Sometimes takes two -three times of re-applying lipstick, fitting, and cutting. Especially when the flange ( is that the proper term?) has been chipped, and a repair ring has to be used.

Okay folks,..just spent 2 hours on my knees removing 1/2 of the top layer of 3/4 inch plywood. To my surprise, I have the original hardwood floors underneath and they are in good condition too!!! I will go back later and remove the remaining top layer of saturated plywood. Circular saw, saw-zaw and oscillating tool with half-moon blade is working wonders here. Plus, an old fashioned hammer and flat bar is doing most of the work once the cutting is done.

I will be cutting new plywood on Wednesday.

To cut the shape on the front of the tub, ( mine all are wider in center of tub, narrow ar both ends,) I use a compass , like we all used back in geometry class, to scribe the shape onto a brown paper bag. Cut off the extra paper, and once the pattern fits the tub exactly, I used that to mark the plywood.

And, be sure to think of where the seam in the plywood goes. I admit, I and not sure where the best spot is to join the two pieces of plywood, other than over a joist. I would love to hear from others on this. My floor space in my bathrooms is five X five, so there is at least a one foot smaller piece. Intuition tells me it might be better to have a two X five piece, and three X five piece of plywood, rather than a skinny one foot piece.

Oscillating saw does not take THAT long as some have said, especially with a GOOD, FRESH blade. (Most important). Other pros for the oscillating saw: Less dust (especially when cutting drywall), better control. Other cons: MUST wear hearing protection, very dependent on blade quality.

For the toilet flange cutout, I use the simple jigsaw with common wood blade. It is narrow enough to make the circle easily without veering off course. You can make a template out of cardboard shoved into the nearest corner and cut the flange cutout into the cardboard with a utility knife and then transfer that to the new subfloor sheet to mark the cutout.

CX,

The seal where the tank joins to the toilet bottom was leaking. My tenant put a coffee can under it and it quickly filled with water and over-flowed. This went on for months, I assume. Tenant was there for 8 months before he skipped out.

I am a licensed contractor with almost every saw (cutting tool) and every type of blades to fit them. If the floor has tile, I'd use a diamond saw (water cooled with a vacuum pick-up) to cut out the tile at the grout seam. Then I'd use the proper wood saw to cut out the sub floor, making sure I don't cut a Joist, wire or pipe.

Circular saws are dangerous for the novice. As the post above posted a oscillation saw works well but the blades get eaten up quickly.

I was surprised it took so long for someone to mention a toe kick saw. Technically it is a door jamb saw. Put a piece of masonite against the tub to protect it. Practice w/ the saw so you get the hang of it because that thing can really take off on you. It has 4 depth settings, so you never cut extra deep. It is the right tool for the job. Get it from HF. Plus you can turn it on it's side and use it to undercut door trim, etc. so your new ply and finish floor can tuck underneath, ffor a more finished look.

The little rockwell saw is an under powered disappointment.

I was in Walmart 2 days ago and noticed in their tool dept, they sell a multi-pack of oscillating blades (like 5 blades in one package) for about $8.50. I bought a pack and used them for this flooring project. They are good blades too! Can't beat the price considering what Lowes sells them for.

And while you are in Walmart, slide over to the Deli and get some Amish macaroni salad which is really delicious.