One thing about foam is that it has ZERO expansion or contraction rates.
So if your layout is in a high humidity area (basement) or in an area of extreme temperature changes (attic) then foam may be the way to go.
I have used some foam on my home layout but the majority of the track sub base is 7/16 OSB board and Homasote over that. The OSB and Homasote are both painted with latex paint, which seems to help control expansion and contraction.
The framework is made out of 1 x 2 - #2 pine.
I try and keep the humidity under control but it will vary from 50% in the winter to over 75% in the summer.
So far the trackwork is not having any problems with kinking even though I have all of my joints soldered!
I built my layout in 5’ modules, using 3/8" Baltic Birch plywood under 1" foam [glued several thicknesses together in places]. The Baltic Birch comes in 5’x5’ sheets. I used 1"x4" ash hardwood around the edges for a frame. The modules are bolted together and set on standard L-girders. Foam alone can be noisey and leaves you with no way to fasten electrical components to the underside of the layout.
Foam is the latest fad. I think we’ll look back on it someday as “that thing everybody tried in the ealy 2000s.”
Pros:
Light weight
You can cut a trench in it
Doesn’t require wood working tools.
You can poke holes in it for trees.
Cons:
No (easy) way to attach a Tortoise or a cable or anything to the bottom.
Unless you’re using modules to take to shows, what difference does it make how heavy it is?
How many trenches do you really cut? For a stream or two, you can cut out the plywood or use cookie cutter.
Doesn’t hold nails – or trees planted by poking holes. Eventually they wobble and tilt.
Track and roadbed must be glued, not tacked. That may be fine, but if you want something a little less permanent, using Atlas tacks is a nice option with plywood. (It may seem like you can easily tack track down with foam, but it won’t hold and eventually your track will shift).
The edges need protection or it gets bunged up.
Noisy unless placed over plywood.
Almost as expensive as plywood – especially the thick sheets.
Contours don’t look as good as those made with hard shell.
I got rid of my foam and went back to good ol’ 5/8" plywood.
Interesting. 5 X 5, huh? You don’t see much plywood in that size.
But anyway, I have had very little noise using WS foam roadbed caulked to extruded foam. You have a couple options on the wiring - you can embed it in trenches in the foam and cover with groundcover (just like the prototype!) or you can tack it to the bottom of the foam with a touch of glue or caulk. Cable ties keep things nicely bundled underneath.
Switch machines are different - you need to glue a thin wood or hardboard plate to the underside of the foam or use Velcro style fasteners (there was an article in MR about the Velcro awhile ago.)
Well I don’t know what kind of foam you are using, but as a proof of concept on my website I am using foam on plywood. I show how I glue it to the wood and itself, using only white glue.
How to hand lay track on it [or use flex track even]. I have NEVER had my track shift. If you don’t count the ceiling falling on my layout LOL.
As for permanance. The flextrack will lift off of the foam very easily IF you are careful and later can be reused. OR you can leave it there till it rots in 100 years. Either way it works.
Noise wise I find plywood much more noisy than foam.
Being an audiophile from way back I know that wood it a muc
Doubtful. I think that Homasote is about to go the way of the dinosaurs, and that foam layout construction is here to stay.
You forgot:
Is faster to construct a layout using foam than girders, risers, spline and hardshell.
Is easier to construct a layout, especially for lone wolves.
Is the ONLY way to construct shelf-type linear layouts.
Is actually cheaper to use than wood and plaster, IF you have to buy everything.
Most of your “cons” show a bias against foam. To refute:
Tell that to Bill Darnaby. His Maumee Route layout is one of the largest home layouts in the country, and he’s got dozens of Tortises and choke-cable signal and switch actuators under his 2" foam. His layout’s been up for almost a decade, and is showing no problems with either working loose.
True, but most of us don’t use foam because of it’s light weight. We use it because of it’s ease of use as compared to wood and plaster.
Have you looked at the ground around a real RR ROW? There’s no such thing as flat ground, especially in the country, which is where 99% of most real track is. ALL track should have some sort of drainage ditch next to it, and according to the Corps of Engineers, the average Midwestern terrain features a bridgable watercourse every two mi
I built my frame out of 1x3 and then a few 1x3 laid flat across the bottom spaced about 18" apart. Then I used 2" pink foam. To give the surface holding power for track spikes, etc., I added a sheet of 3/16" baltic birch plywood. In the built up areas: grades leading to bridges (there must be a rr term for that feature) I use more foam glued together. So far, so good.