great stuff foam to fix hollow spot

[rieferman]

So, I have my kitchen gutted because of a recent flood (dishwasher valve burst) and we took the opportunity to fix flooring between the entry and the kitchen.

To do so, we ended up glueing luan down in the entry area. There's one spot about the size of a basketball where there must be a very slight dip in the surface underneath because the luan has a hollow drum sound just in that one spot.

So, rather than ripping out a very well-glued (and intricately cut) piece of luan, I plan to drill a few holes and spray in some great stuff foam. The extra holes should allow excess to escape, and the void should be filled. Flush cut the excess that oozes out. Once cured, that foam is tough and should hold up in such a small area.

Flooring installer that I like and trust felt good about the approach. Various items I could find on google support the theory as well. But of course, I trust GJ above all else!

Agree or disagree? (also, tight timeline and intricate cut... so re-doing the piece, although not impossible, would be a real pita... and yes, I learned that I should check in ten directions with a straight edge before glueing next time! ha ha)

edit: surface underneath is ceramic tiles, so nailing is not an option

 

[ToolUsingAnimal]

Sounds like it'll work, at least to fill the gap. If you go that route, I'd use the window and door great stuff in the blue can. Regular great stuff expands pretty aggressively, and could bulge a little. The window and door is made to expand less so it doesn't distort window and door frames.

But maybe I'm just paranoid

 

[rieferman]

My thought with the window/door stuff is that it doesn't cure to as hard/tough of a finished product. To combat potential bulging issue, I was thinking relief holes combined with some weight on top of the area (so that the foam would choose path of least resistance through the relief holes).

 

[csp]

I wouldn't say that the regular stuff cures to a hard/tough consistency.

Maybe some sore of epoxy would be better for the job or even a self-leveling concrete in a mix that could go through the holes. The expanding foam is going to break down as you walk on the floor.

 

[rieferman]

No, not rock hard, but under a "spread out compressive" type of environment (such as luan over concrete) it ought to be tough enough to stop the drum sound don't you think? Like a tougher version of a carpet pad.

edit: just saw your edit.. About the break down over time... what about construction adhesive? I happen to have a bunch of tubes already of liquid nails type of product.. I could drill the hole to match the nozzle on the caulk tube.

 

[djjsr]

... what about construction adhesive? I happen to have a bunch of tubes already of liquid nails type of product.. I could drill the hole to match the nozzle on the caulk tube.

PL has some self leveling urethane in a caulking tube. It's thin enough to flow and sets up like rubber in a day or 2 depending on temperature. I filled a gap between a brick wall and a sidewalk with it and it works great.

 

[Tink]

I'd go with the liquid nails and some relief holes so you don't have any air pockets.

 

[draglink]

There a syinge kits that come withan epoxy, drill bit and syringe. We use them if there is a low spot in a slab that the hardwood adhesive doesnt hold. I order them from a supplier by the case, check Lowes or HD.

 

[Frank The Plumber]

Pull up the luan and do the job properly.

 

[csargents1546]

Second pulling up the luan.

 

[rieferman]

Being the hack that I am, I tried the foam fix. Worked like a charm. The vinyl that's being installed will be edge glued by the installer so I have a back door to repair if needed. And if not, I learned a new trick.

 

[rpmgroup]

having used a few cans, these stuff seals on the edges as it expands, but stepping on it between the two surfaces will allow it to crack and break up. any water would be soaked up in the open cells and either be pushed out under pressure as it is stepped on, (think high pressuse spray) causing more to break up or could start to mold. I would use epoxy with a needle.

 

[rieferman]

It's a very small spot, less than 1/8" of dip filled, not near water, and covered w linoleum (ie nothing can disturb it). Plus it's already finished and working well so far. The covering is a floating vinyl so future repair is able to be easily accomplished, but I suspect the repair will hold up.

 

[rieferman]

Well, I'm willing to admit when I was wrong! So, here goes:

That damn hollow spot was fixed by the foam... Until the last couple of days when the foam has broken down, and now it's making the annoying noise again.

So, into the honey-do jar goes the task of rolling back the flooring and fixing the hollow spot properly (it's a floating floor, and the spot it near an edge, so not a big deal.. but still)

Ok.. all at once now: "We told you so Bob!!!!!!!!"

 

[tomsteve]

justa noob here, but i think a polyurethane glue would be stronger after it has expanded and cured.

 

[MoonRise]

Takes a big man to admit that they f'ed up, so Props to you for that.

But the 'quick fix' sure broke-down pretty darn quick, eh? Didn't even last a month.

How's that saying go again? 'Do it right or do it over'?

 

[green.bubbly]

I am still with the injection of some sort of glue crowd. Although I would suggest some sort of two part epoxy or two part glue that does not need air to dry.

 

[draglink]

Try DriTac syringe kit, 2 part epoxy.....works great!

 

[tcianci]

Why try to engineer a solution to a problem thats been solved for years. Frankly, I'm surprized that your flooring installer didn't suggest just nailing the deflecting area down hard and applying standard floor leveling compound. It's made for exactly this type of situation and the repair is suitable to be covered with the flooring material.

 

[rieferman]

I'd definitely nail it, but it's anicent ceramic tile over concrete slab underneath the luan (we left it in place because: 1) it made it so that finished height was perfect, and 2) it seemed like removing it was an awful hassle/mess for little gain). We didn't think we'd be able to get anything to penetrate it. What do you think? Would ramset go through the tile? Or drill and screw?

Thanks again for all the ideas, much appreciated!

 

[tcianci]

Well, that's a horse of a different color! You don't want to do anything that attemps to penetrate that old tile. In light of this situation, I would score the faulty luan out of there with a utility knife and use the floor leveler.