Foam/Glue Problem

[jacon12]

This morning I noticed I have what seems to be a section of the 2 inch extruded foam base separating from the plywood topped benchwork. As you can see in the photo the rear most half has risen about 1/4 to 3/8ths inch in this area..

I know that I was very liberal with the Liquid Nails for Projects and foamboard on the entire layout, so I'm guessing that the culprit may be the wall mounted AC unit under the bench..

The room is well insulated but the ac is not kept on all the time. It never gets hot in the room but I do live in Georgia, very well known for high humidity. The coming on and off of the ac may have set the stage for this happening. My question is what is the best way to handle it?
Remove the track and cut out this section and reglue it or what?
Jarrell

[orsonroy]

I'd reglue the snot out of the foam and hope for the best. Be sure to add CORK roadbed to this area, and to not glue it down very well. This will give you some "float" around the joint in case the wood below decided to swell on you again.

[Anonymous]

I'd suggest that you don't need to remove the foam to re-glue it. I'd suggest drilling a hole though the foam but not the plywood and pushing the glue through that. You can feel around and find where it's come loose and inject it into those places. Weigh it down with something heavy while it dries.

Mark in Utah

[jacon12]

Ray, I'll remember the cork roadbed idea and not glue it down in that area. Thanks.
Jarrell

[jacon12]

QUOTE: Originally posted by mark_in_utah

I'd suggest that you don't need to remove the foam to re-glue it. I'd suggest drilling a hole though the foam but not the plywood and pushing the glue through that. You can feel around and find where it's come loose and inject it into those places. Weigh it down with something heavy while it dries.

Mark in Utah

Mark, that sound like a good suggestion. I might even try cutting a square plug out, maybe a couple of inches square, so that I can get the tip of the glue tube angled enough to get some under the foam and then replace the plug. Its a wonder that someone hasn't tried placing a very flat, thin piece of metal on seams such as this and screwing it down to the plywood and then sceniking over it.
Jarrell

[WM-skipper]

You might also fasten a panel to the underside of the bench to deflect any flow from the air conditioner. I'ld also mount speaker-box insulation and a vapor barrier on the bench side of the panel.

[pcarrell]

Investing in a dehumidifier might be wise. Even a small one would be better then nothing. A small one could even go under the benchwork right next to the offending culprit (the air conditioner). Probably wouldn't hurt for the rest of the room either!

scottghall stole my other suggestion! [:D]

[jacon12]

QUOTE: Originally posted by scottghall

You might also fasten a panel to the underside of the bench to deflect any flow from the air conditioner. I'ld also mount speaker-box insulation and a vapor barrier on the bench side of the panel.

I have installed a deflector panel under there but I might insulate it also.
Thanks!
Jarrell

[jacon12]

Thanks PCarrell and everybody for the suggestions.
I cut a 2 inch or so hole in the foam and pulled out the plug, had a looksee and guess what I see! It looks as though the plywood did a dipseydoodle on me and I didn't notice that the glue had not caught, or rather had not caught good, the end of the foam. Here's a drawing of what I mean. The dotted line represents the end of the plywood and its exageratted for better clarity.

So I put a good bit of Liquid Nails down in the hole and then took a bent saw blade and worked as much as I could underneath, put the plug back in and then put about 30 lbs of books on it. I'll leave it that way for a few days and then we'll see.
Thanks for all the suggestions.
Jarrell

[canazar]

Jacon,

If you run into a problem agian, I found a quick fix, out of frustration one nite, but ended up working well. I took a ling dry wall screw on a fenderwasher (a regular washer but with s super wide shoulder) and screwed the sucked into the wood. The washer put alot of presure and gave it a very secure grip. Yes, I did have a slight impression, but I just used my scenery materails and covered it up just fine.

I had a spot lifton me too in the back corner. I think I forgot to use enough glue, and fixed it that way. Anyways, just .02cents.. [:)]

[Anonymous]

This is a good example of why you should paint or otherwise seal the wood parts of your benchwork before moving on. I know it is a pain in the rear, but foam subroadbed, scenery, even track do not move nearly as much as the wood does.

Andrew

[bogp40]

Jarrell,
A deflector as you have installed is fine, but I wouldn't cover the underside of the plywood with anything but sealer or paint. Any covering or moisture barrier can cause condensation, especially in such close proximity to the A/C unit. During extreme humidity w/ the unit blowing, you could end up w/ a real bad moisture problem even mold.
As a carpenter, I cannot stress enough how important it is to use quality plywood, may not be the case here, but the better grades of ply from "real" lumber yards would shurely almost eliminate warping or delamination.
Bob K.

[jacon12]

QUOTE: Originally posted by canazar

Jacon,

If you run into a problem agian, I found a quick fix, out of frustration one nite, but ended up working well. I took a ling dry wall screw on a fenderwasher (a regular washer but with s super wide shoulder) and screwed the sucked into the wood. The washer put alot of presure and gave it a very secure grip. Yes, I did have a slight impression, but I just used my scenery materails and covered it up just fine.

I had a spot lifton me too in the back corner. I think I forgot to use enough glue, and fixed it that way. Anyways, just .02cents.. [:)]

And I've got a whole box of those super wide washers. Thanks for the tip!
Jarrell

[jacon12]

QUOTE: Originally posted by masonjar

This is a good example of why you should paint or otherwise seal the wood parts of your benchwork before moving on. I know it is a pain in the rear, but foam subroadbed, scenery, even track do not move nearly as much as the wood does.

Andrew

Andrew, lets chalk it up to a learning experience (I'm gettin' lotsa those!).
In the future when someone asks I think I'll recommend just what you say.
Jarrell

[jacon12]

QUOTE: Originally posted by Robert Knapp

Jarrell,
A deflector as you have installed is fine, but I wouldn't cover the underside of the plywood with anything but sealer or paint. Any covering or moisture barrier can cause condensation, especially in such close proximity to the A/C unit. During extreme humidity w/ the unit blowing, you could end up w/ a real bad moisture problem even mold.
As a carpenter, I cannot stress enough how important it is to use quality plywood, may not be the case here, but the better grades of ply from "real" lumber yards would shurely almost eliminate warping or delamination.
Bob K.

Thanks Bob, I appreciate it. The plywood in question is the 15/32nds interior use type. I've tried to seal the room from humidty and I may get a humidifier if problems persist. I've not been running the AC all the time, usually turning it on around noon and running it until 9 or 10 at night but that may not be enough.
Jarrell
Jarrell

[Anonymous]

QUOTE: Originally posted by jacon12

Jarrell,

It looks to me like the join in your blue foam is at the same location at the join in your wood surface below. If that is true, (and it's not merely a mark or a shadow) you may want to offset the joins.

If it's just a mark or a shadow I with draw my suggestion post haste[(-D]

Trevor[:)]

[pcarrell]

QUOTE: Originally posted by jacon12

QUOTE: Originally posted by Robert Knapp

Jarrell,
A deflector as you have installed is fine, but I wouldn't cover the underside of the plywood with anything but sealer or paint. Any covering or moisture barrier can cause condensation, especially in such close proximity to the A/C unit. During extreme humidity w/ the unit blowing, you could end up w/ a real bad moisture problem even mold.
As a carpenter, I cannot stress enough how important it is to use quality plywood, may not be the case here, but the better grades of ply from "real" lumber yards would shurely almost eliminate warping or delamination.
Bob K.

Thanks Bob, I appreciate it. The plywood in question is the 15/32nds interior use type. I've tried to seal the room from humidty and I may get a humidifier if problems persist. I've not been running the AC all the time, usually turning it on around noon and running it until 9 or 10 at night but that may not be enough.
Jarrell
Jarrell

Thats DEhumidifier! I think that was a typo on your part but I wouldn't want the problem to get worse.

[selector]

The long coarse screw and large washer idea immediately came to my mind, as well. You should use a couple along that join, maybe even three, and counter sink the washer and screw/bolt head somewhat so that you can tape over it, or plaster over it to conceal it.

[jacon12]

Trevor, I've wished a hundred and one times that I had been more careful about where the end of the foam was in relation to the end of the plywood. If I had only staggered it there would be no problem.
Lesson learned.
IF this doesn't solve it, and the screw method doesn't... then I'll take my knife and cut out pieces of foam about 18 inches long on both sides of the seam, cut a piece to fit and glue that sucker down good right across the seam.
I hope all you other beginners are taking notes.. [:D]
PCarrel, DEhumidifier it is!!
Crandell, maybe I didn't understand the original answer. I thought the screw/washer was going down through the 2 inch foam and bite into the plywood enough to pull the foam down level, thus no need for countersinking etc.
Is that not right?
Jarrell

[selector]

Not to my way of thinking, Jarrell. I though you would merely want to get it back flush, surface-to-surface with the adjacent piece. If it is lifted by, say, 3/8", then you want to reduce it by that amount...only. I see no need to reef it all the way donw to the slanted butt-end of the plywood below it. In fact, the better solution, overall, might be to do as you were just saying...cut a plug, glue it to the plywood to fill the gap, and then reglue the big sheet to the plug; no need for screws. Either way, it should work. I would personally use your method. Fast, less complicated, less like modern surgery on a broken femur.

[jacon12]

QUOTE: Originally posted by selector

Not to my way of thinking, Jarrell. I though you would merely want to get it back flush, surface-to-surface with the adjacent piece. If it is lifted by, say, 3/8", then you want to reduce it by that amount...only. I see no need to reef it all the way donw to the slanted butt-end of the plywood below it. In fact, the better solution, overall, might be to do as you were just saying...cut a plug, glue it to the plywood to fill the gap, and then reglue the big sheet to the plug; no need for screws. Either way, it should work. I would personally use your method. Fast, less complicated, less like modern surgery on a broken femur.

Ok, I got'cha... we were thinking the same. I just want it back flush with its counterpart and no lower. I guess I just gotta wait til the glue dries before finding out if it works. I sure hope it does but if not, I'll try the screw method.
Jarrell

[Medina1128]

Whenever I join two adjacent sections of foam, I always stagger cut the foam, so that the top of one section overlaps the section next to it. That way, you can also glue each section to the one next to it. And it's stronger than just trying to butt the ends against each other.

[oleirish]

Jarrell ; I have a question? When you put your bench work togethor ,how did you secure the plywood to the frame work??When I anchor the plywood to the bench work I use SHEETROCK screws,I counter sink them and then fill them in.I have never had the plywood come lose.

JIM

[selector]

Jim, his plywood is okay, except that one end has a champhered, or bevelled edge, and he unwittingly missed that when he glued. So, his foam sheet, at that edge, has lifted at one corner because it was unsecured. The plywood, itself, is firmly held to the benchwork.

[Bikerdad]

Unless this is a yard, why mess with the benchwork? Take a surform rasp to the joint and rough it up. Incorporate it into the scenery, use cuts and fills to get your track across the joint, etc.

[selector]

Good point. I guess Jarrell has to decide what he can live with. Maybe he want's to get this put right so that it becomes part of his learning.

[jacon12]

You're all correct. Lesson learned: never butt join the foam over the butt joint of the plywood! Never.. [B)]
Crandell is right in that the foam didn't adhere to the beveled portion of the plywood. If I had done the above, there wouldn't be a problem. The plywood is held down by sheetrock screws that are countersunk. There's even Liquid Nails in some places. I've had the 30lbs of books on it for about 24 hours now and will leave them until at least tomorrow. If that fails to hold it I'm going to put a couple or three screws/washers in it just enough to bring it down some (or to secure any further separation) and get out the rasp and maybe make a stream bed there![^]
Jarrell

[orsonroy]

Actually, a waterway or ditch isn't the worst way to handle a badly-behaving foam joint. I've had to resort to that trick a couple of times...

[oleirish]

QUOTE: Originally posted by selector

Jim, his plywood is okay, except that one end has a champhered, or bevelled edge, and he unwittingly missed that when he glued. So, his foam sheet, at that edge, has lifted at one corner because it was unsecured. The plywood, itself, is firmly held to the benchwork.

Thanks I guess I looked at it wrong,sorry!!
Jim