Termite damage in subfloor


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Old 02-24-05, 04:16 PM
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Termite damage in subfloor

I don't know if this question should go to to flooring or to tile, but here goes: Our house is post-and-pier construction and was built in 1973. The basic floor of the house is 1" plywood (I know this from ripping up carpet, etc. in the past). Actually, it's the only floor. The bathrooms had originally had the world's ugliest linoleum which the previous owners had replaced with tile. I am now renovating the guest bath and when I took out the toilet, I saw that the ugly lino was still in place under the toilet fixture. I assumed they just tiled over the old lino. I've just spent the day pounding the tile out of this bathroom and find that although the ugly lino had in fact been taken out everywhere except under the toilet, the tiling was done by spreading mastic directly on the plywood subfloor. As I was pounding on the tiles, I noticed to my horror that the subfloor had apparently been invaded by termites. From what I can see so far, the damage is rather extensive, eating down about 1/4" of the plywood in numerous and sometimes large areas. I was planning on ripping up the lino, scraping the mastic off if I could, then putting a layer of thinset to bed the concrete board on top. New tile on top of that. Now I don't know what to do. If this floor were to collapse, it would be a disaster since there is about a 10' drop below. I can't really tell how deep into the wood the damage goes. Should I treat the floor for termites and then fill the damaged areas with a levelling compound? Then proceed with thinset and concrete board? Am I going to have to tear out the subfloor? What should I do?
 
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Old 02-25-05, 04:23 AM
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Bummer, I hate when you plan for the best and the worst shows up instead. If that's termite damage you've got the answer is yes, tear out all of the damaged subfloor and keep your fingers crossed that's all the damage you have in there. My guess is at least part of the floor joists will have been feasted on already by the pesky bugs. At this point your best bet is to attack the rest of the floor demo with a couple of pry bars and try & get the plywood up in sheets or as big of pieces as you can. Get that garbage out & away from the house asap! Once you get that out of there you'll have to assess the joists to see what kind of condition they are in, odds are good you'll have to replace at least one or two of them.

When you get the framing taken care of I'd definitely treat everything down there to keep the termites at bay and get the yard spike type system to rid the area of termites. If you have a firewood pile or any brush up next to the house get it away from the house as well. We had to rebuild the entire garage door opening frame for a client last spring due to termite damage. She has alot of trees in her yard and as sticks & whatnot fell out of the trees she had been piling them up on the edge of her drive right next to the garage door for years. Termites had migrated from the wood pile to her garage and destroyed most of the framing in the front of the garage. This all ended up costing her a couple of thousand dollars to repair. Her son installed the termite control spikes bought from local hardware store (sorry don't know the brand name to recommend) and to date no new problems reported.

Anyway back to your retiling project, if you're planning on having tile in there like porcelin, ceramic, etc., I would come back in with a good grade of exterior rated plywood and cbu over that for a substrate for tile. But before we get to that point the size, condition, span & spacing of the floor joists needs to be checked out to insure it's suitable for a tile install.

Post back once you get the subfloor tore out and let us know about the info I've listed above and we'll go from there. Good luck.
 
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Old 02-25-05, 11:55 AM
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Thanks so much for the help on this one! My first inclination is also to tear out the whole floor, but it's a real problem. It's a very small guest bathroom and the walls are sitting on about half of one 4'X8' plywood sheet and a about two feet of another plywood sheet. There is no whole sheet to pull out without pulling down walls. To get the larger of the two pieces out, I'd have to pull out the tub and all the brand-new tiling around it that I've spent two weeks on! Please! I could cry! I spent all of yesterday afternoon poking and digging and I think I have defined most of the damaged area, the heaviest being centered around the toilet drain hole. It also doesn't look like it goes all the way through. It also looks to me like it's old damage. (We had the whole house treated for termites with Borate three years ago and they treated the subfloor very thoroughly.)

The one bright spot is that the house is up in the air and there is more than enough space to work under the room. I'll get my termite guy to do some real work and inspection on the joists and surrounding subfloor Now: is there some way to pull that subfloor plywood out from under walls without demolishing the walls? Could I use a reciprocating saw and just cut out the damaged sections? Then how would I brace them underneath? With bridges?

Sorry to be such a bother...

Tina
 
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Old 02-26-05, 05:56 AM
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NO bother Tina, that's why we're here. Ok here's what you do, break out your circular saw, or a wormgear saw is even better to use, but a circle saw will do. If you don't have one one you need one anyway so go buy yourself one girl. (you can also rent them for a few $ a day) Anyway what you do is determine the thickness of the underlayment material. You should be able to determine this by looking around the drain, then set the depth of the blade on your saw so it will just cut thru the underlayment, but NOT into the joists too much. Now snap youself some lines on the floor around the damaged area, and cut out the area with the saw. You just need a steady hand when you dip the blade down into the line, you'll have to pull the guard back with your free hand, BE CAREFUL, we don't want no missing digits, I really hate when that happens You'll have to cut just past the corners to cut the underlayment all the way thru, do this for all four sides, then use a pry bar to lift the bad piece out. You should install bridges between the joists then so the edge of patch, both the new & old wood can be screwed down tight.

You should put another layer of plywood over this if you before you tile here. I assume you've already worked the numbers on the floor deflection for your floor tile since you've already done the tile around the tub.

Hope that helps, keep us posted.

 
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Old 03-08-05, 05:37 PM
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I did it! I did it!!

When I found this little hitch in my plans, I was almost overwhelmed with the possible repercussions that I was facing, but thanks to your help and advice, I just decided to get on with it! And it worked! This girl can saw, I tell you! Since my sawing through the subfloor wasn't as straight as I'd have liked and since there was an area that I had to do by hand (really tight little corner) the piece I took out wasn't exactly square, so I laid the new plywood on top of the hole, went underneath the house and drew the outline of the hole onto the new wood. Then I cut the new wood on the lines and it fit in perfectly! Then I put in new 2X10 bridges on the joists underneath to support the edges (that part was a real ***** because they had to line up with the cut line and it's hard to hammer one bridge in line with the next; also had the hammer fall on my head while moving the ladder. Ouch!). Then I screwed it all down, sealed the joints, put down an additional 3/8" plywood, then thinset, then 1/4" Hardiboard. Then I tiled it. And it looks beautiful and feels solid as a rock! I also had a termite guy come out and inspect the whole area, including the wood I'd removed. He says it's all previous damage and all the critters are dead. He also inspected under the bathroom area, all the joists and surrounding wood and didn't see anything. He thinks the critters got in through the hole for the closet flange. For the new whole I'm going to seal it off with that expandable foam stuff. Good tip because the interior of the wood was the only damaged areas so they got in through the vulnerable ends.

Anyway, thanks a million!

Tina
 
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Old 03-12-05, 08:53 PM
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Good deal Tina! Glad we could help. Any chance of some pics of the finished project?
 
 

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