Foam will warp, especially the pink stuff if under presure. It will warp the white beaded stuff too but put it on a flat surface and it will warp back into shape. The thocker the foam, the less likely this will happen. Also the foam specks are for ungassed foam, shrinkage of outgassed foam is unmeasurable, at least with the white beaded stuff (which I use as other was not available when I started where I live).
Three thoughts.
1. Back when styrofoam was a new-ish product (not the extruded stuff, but the foamy stuff like florists use) there were all sorts of excited articles about it in MR and some guys reported that it seemed to shrink over time. The thinking at that time was that, in an era when most people had oil heat in their homes, that were was something about burning oil in the furnaces used back then that released fumes that over time attacked the more flimsy and airy kind of plastic foam. That was also the time when people discovered that leaving a lemon slice in a styrofoam drinking cup would attack the foam. It wasn't the lemon juice per se it was the organic solvents that are in lemon oil.
And we all know what certain paints and adhesives including some versions of Liquid Nails can do to plastic foams. Including extruded.
2. Some years ago I purchased a display track from a hobby shop that was going under. About four feet long, maybe longer. Made entirely of plastic foam (so no wood or other material), with two lengths of track on two levels, nicely ballasted and scenicked by one of the many great modelers who owned and ran that shop. I have used it for photos to illustrate articles I write for the NMRA Midwest Region Waybill. Stored entirely in my basement, and stored flat. A couple of years ago the track started to heave up and tear away from the ballast. What I think is that over time something in the adhesives used for the track, or the ballast or scenery, or perhaps to attach the multiple pieces of styrofoam to each other, gave off gases and over time started to push away from the foam.
I wonder if over time our OP used track cleaning liquids, or had used adhesives on the layout or other materials that chemically acted like organic solvents? Or something "in the air" in his garage over winters from exhausts etc?
3. Many years ago I added weight to a freight car model and attached the weight with Walthers Goo. I did not know that over time Goo releases gases that might or might not be organic solvents. The car interior was evidetly sealed tight and the car "expanded" like a hard balloon and bent the plastic. What I learned in an Andy Sperandeo column was that I should have drilled small holes in the floor or elsewhere on the model to let those Goo gases escape. In fact Andy himself chastised me in the pages of this Forum for not following his advice.
I agree that if left alone you'd think the extruded foam by itself should not warp or change. But if it is a full layout it is not "alone." There may have been adhesives, paints, or other materials in the construction of the layout that attacked the integrity of the foam. Things like track cleaning materials were used that soaked in. Or it may have been exposed to fumes in the air in that garage in one particular season.
Dave Nelson
UNCLEBUTCHUp here in WI, they store it in steel warehouses, I see it out side sitting in snow banks.
Very true, on job sites, it sits outside until it's used. Hot summer or cold winter buried in snow. We get a semi load. The biggest hazard was the wind.
It's not the foam.
Mike.
My You Tube
I have never heard of or seen foam warp.
Up here in WI, they store it in steel warehouses, I see it out side sitting in snow banks.
You don't really need a frame.
As stated above, you got something else going on.
I would use 2 inch foam, and cross braces below it in the frame.
But, I agree that the foam itself is probably not the problem.
It takes an iron man to play with a toy iron horse.
I agree with Randy, the wood is the problem not the foam. Steel studs are cheap and humidity does not affect them. You can also use caulk to attach the foam to the wood, it has enough give to let the wood expand and contract without bending the foam. A glue like PL 300 make the foam and wood one, think expansion plates on a bridge, thats what using caulk will do.
Brent
"All of the world's problems are the result of the difference between how we think and how the world works."
13 years in the forum and you are probably still on moderation.
We can't see anything of your pics, but I'll take your word for it.
There was a link off the How To tab of construction with ripped plywood as the bench work, 16" joists and 2" foam. I posted it several times in the forum (and it was also an article in MR) but I can't find it now.
I did that except put 1/8" luan plywood on top the joists and glued to the foam. Mine sits in the basement so it is not subject to extreme temperature changes.
I can easily manage the 2x5' module myself. I also have a 2x7.5' long piece, it is unwieldy for one person, but not heavy.
Henry
COB Potomac & Northern
Shenandoah Valley
More likely the wood frame shrank due to the low humidity. According to the Dow data cheet, the thermal expansion of the blue extruded foam is 3.5x10^-5 inches per inch per degree. So a 120 degree temperature swing on the 5 1/2 foot side would change the length by little over 1/4".
Perhaps frame it in steel studs? Not sure about the thermal expansion, but pretty impervious to humidity change throught he seasons.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I built a small layout (about 5-1/2 ft by 4 feet) using blue foam base in a frame box. When not in use it suspends between roof joices in the garage. During the winter I can pull it down, tip it on its side and walk it inside to sit on the kitchen table. For three years everything has been fine. But this winter the foam loosened and warped. The center has heaved up and now track is no longer level. My trains are tipping out. Its not severe or but at higher speeds some engines and cars derail because the lean out. I'm debating a rebuild of the same track plan but need to think about a different material that won't move due to winter storage in the Chicago winter. Anybody have any thoughts about what to use. I don't have space for a train room and can't even store my layout inside the heated house so whatever I do has to light enough to move easily but strong enough not to warp or break down with changing temps and weather condtions.
As you can see the entire layout is about 6"deep and the frame is about 1-1/2" of the 6". I also have to think about a quick turn around if I do a complete rebuild because I have to work in the garage, so I have about 3 to 4 months of time to work on it before it gets too cold for glues and paints to cure completely.