Questions about WS foam SubTerrain system

Hi All,
I’m new here, and I plan on introducing my Nephews to Model Railroading this Christmas after being out of it myself for about 12 years. A lot has changed…especially the prominance of foam and the Woodland Scenics SubTerrain system.

I’ll be helping them get started with a basic 4x8 layout. I plan on using 2" thick extruded-foam insulation as the main risers for the track sub roadbed (on top of a 1/2" plywood base), with Woodland Scenics Incline sets to create rises. I also plan on using the WS Track-Bed and Atlas Code 83 Snap-Track. I will be using a Low Temp Glue Gun to adhere the foam risers to the plywood base, and to glue the inclines to the risers (per WS instructions)

In researching the WS SubTerrain stuff I’ve found that they say to cover the foam sub-roadbed (inclines and risers) with a single layer of dry Plaster Cloth (to create a “hard-shell”) then to wet it with water from a spray bottle, and smooth the plaster with your fingers. Then sanding if necessary. They also suggest sealing the Plaster Cloth with Flex Paste to help keep water from leaking into the Plaster Cloth and loosening the roadbed (when laying ballast or spraying water around the track for any reason).

My questions are these:

a. Has anyone here used the WS Plaster Cloth over foam SubTerrain system? And if so, what are your thoughts?

b. If I go that route, is there another or better way to “seal” the plaster cloth shell rather than using WS Flex Paste? Would painting all the Plaster Cloth with latex house paint keep water from soaking into the plaster? Would it work as well as the Flex Paste? And is this step even necessary?

c. I’ve seen a lot of people here recommend Paintable Latex Adhesive Caulk as the best choice in glueing down WS Track-Bed to the sub roadbed (plaster cloth on foam shell)? Caulk also appears to be pretty cheap. I’ve also read on here that Elmer’s white glue is a popular choice as well. WS obviously pushes it’s 'Foam Tack Gl

I can answer SOME of your questions, the rest I haven’t gotten that far in my building yet. I too come from the plywood and cork days, and wanted to go with something newer/better this time around.
First, I assume this tabletop you are building is going to have some sort of framework holding it up - if so, you really don’t need the 1/2" plywood under it, the 2" foam is more than sturdy enough to support itself. My layout is more shelf-like, I built units that are 2’x8’ from 1x4 lumber, with cross pieces on 16" centers, and my foam is going nowhere.
As for the Track-Bed, I WAS planning to just use cork like I have in every other layout I built. But at a recent local train show, I got 2 of the boxes of 24’ rolls of it for a price I could not pass up, so I decided to test it out, if it didn’t work, no big loss. I pinned down some track on top of each, and the Track-Bed is DEFINITELY quieter. About the only thing I don;t like is that it’s not as easier to sand transitions - I put my sidings at a lower level than the main line, and you can’t just have the track suddenly dip down (unless you want constant derailments), so I need to sand down a transistion area. It does sand, it’s just a bit messier than cork. As for splitting it - I have 30" minimum radius curves on my main line, and it handles that easily. I think curving it to 18" radius is going to be tough without splitting it. I was worried about that, too - then I noticed something. Like cork, they already have the split part way through, even ont he long rolls of the stuff! Just partly fold it in half and you’ll see the seam open up, and a quick pass with a hobby knife and it’s done. Cuts far easier than cork does. I cut away one side to make the transitions at sidings.
For fastening it all down, I asked this prior to starting and there are a few options. First of course is the WS glue. I saw that, and I saw the price. It looked like white glue, and now with your information about sealing it up so water won’t lossen the roadbed or track, I r

Hi Dave,

Having built two of my own home layouts out of foam, as well as helping four others with foam layouts and building about a dozen Ntrak foam-based modules, I’ll see if I can answer some of your questions. Although I haven’t used the WS foam terrain system, foam all pretty much acts the same way when building a layout.

They’re trying to sell you their products. There are other, as effective, less expensive alternatives to everything WS is trying to sell. To start off with, you don’t need to use ANY plaster with a foam-based layout. Anything you can do with plaster, you can do with foam alone, including rock formations. Build up your scenery contours with foam, and sand and carve the foam to shape. If you wind up with gaps in the foam sheets, use “Great Stuff” spray foam in a can to fill them in. The final scenery layer will hide any joints.

WS flex paste is basically a plasticized joint compound. You can buy one gallon buckets of the stuff for less at a home improvement store. Interior latex (one thick coat) will seal plaster cloth just fine.

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I’ve seen a lot

Wow, Thanks guys! Great information!!! I’m really excited to try this system and get back into the hobby.

And sorry about that duplicate question on the Paintable Latex Caulk…I thought I had accidentally deleted what I first typed, and re-typed it. I guess both paragraphs ended up appearing.

Thanks again!