In planning a new 12x15 HO layout, I decided to use 2" foam over ½" plywood until today.
I researched expanded polystyrene only to find they come in different densities. Owens (pink) markets “FOAMULAR 150” and 250. The difference is density and compressive strength. I presume the measure is in weight per cubic foot, 1.5 lbs vs 2.5 lbs. In any event, the 150 at my local Home Depot in 4x8 1" sheets is $11.60 a sheet.
Homasote is a brand name product for fiber board. My Home Depot carries Georgia Pacific “Stedi-R” exterior sheathing. A 4x8 ½" sheet is $4.50.
The compressive strength and lateral stability of the Stedi-R (Homasote) was twice that of the 150 foam. The 150 would not be suitable, in my opinion, for layout construction. It’s too soft. I imagine that a 2" sheet of 250 foam would be stronger and more rigid as well as more costly.
From my fact finding mission, I have decided to go with the sheathing (Homasote) over plywood and skip the foam.
What are you putting on the foam, is it going to hold a model railroad or are you planning on walking on it, foam on 1/2 plywood will or would have been fine.
Are you sure that you are using homosote? Or, are you using a by product that is labeled homosote? I have not seen homosote in northern Ohio, Pa. for $4.95 a 4 by 8 sheet in over 40 years.
I bought at my local lumber yard in Greenville, Pa., homosote 4 by 8 sheets for $20.00 a sheet 5 years ago.
As to Homasote vs Foam. What are you doing with it? As long as you’re not standing on it, Foamular is an acceptable layout surface. It’s easy to cut and form and is dimensionally stable. However, it doesn’t hold nails or screws, and acts like a sounding board.
Homasote is easy to drive nails into, a plus for handlaying. It’s also nearly silent. However, being paper it doesn’t like water. I’ve never had a major problem with it swelling, but some people have. Homasote actually mentions MRRing as a use for it’s 440 Soundboard.
I have pink foam from Home Depote and Blue from Lowes, which is stronger? Out side edge of the K-10 Mining company will have 1/2 plywood under it and is a open gride with 16" centers based on 2" X 4". I was going to use 2" foam on top of the plywood and center of the track is a Cookie Cutter set up.
The choice between Homasote and foam depens a lot on the difference in track construction and how you want to build elevations.
If you are handlaying track then Homasote is way better than foam. If you are glueing flextrack to cork roadbed, its a wash.
If you want to use stock “ramps” at set % of grade to go between levels and it doesn’t matter if your levels are even multiple of inches then you won’t mind foam. If you want smoother transitions between levels, total flexibility of grade and relative elevation, or the relative thickness of the roadbed is an issue (helixes, multiple levels, lots of hidden track), then some form of plywood or plywood/homasote laminate would be more in your line.
Pink is an Owens Corning product, Blue is by DuPont. Both come in varying densities. The density makes the difference.
As far as strength. I am not concerned so much by the actual strength but by the ease at which the FoamulaR 150 compresses. To much flexibility could be a bad thing for track alignment
Is there that much difference between Homasote and Stedi-R ?? I haven’t handeled Homasote in 30 years. My last road was a 6x8 “N” that I did in cookiecutter. Seems to me that the Stedi-R is just as good.
If you want Homasote, here’s a Dealer Locator: http://www.homasote.com/WhereToBuy/ I was surprised to find a Lumber Co. less then six miles from my house that carries it. Cool. I had noticed the Stedi-R at Lowes and found this thread doing a search for Stedi-R and Homasote
Your comparing apples and oranges so to speak. A lot of guys use extruded foam for scenery material such as mountains, landforms, rivers etc. Where Homasote is basically used for sub roadbed and level areas to place ground cover tress etc. When one chooses Homasote you typically use hard shell scenery methods, plaster cloth over wire or cardboard strips, red rosin paper and white glue over cardboard strips etc. I use homasote over 1/2" plywood and in some area’s 3/4" plywood, why the over kill, because I had the plywood and why not use what you have before you go buy new stuff. It is advisable to use plywood over top of bench work where permissible to add strength. One poster asked what are you walking on it, well as a good practice your bench work should be able to support at least your own weight. Think about the possibility of what may happen once you have track work scenery etc. all in place virtually a completed layout and you need to get to a hard to reach part of your layout and you lean on the bench work or better yet a visitor makes the mistake of leaning on it and crash down comes all your years of hard work and money into a big heap of junk. A little bit of over building usually isn’t a bad thing when it comes to bench work. The little bit of money you save from building light weight bench work isn’t worth the trade off. Same can be said for modular layouts. Yes they need to be light weight or shall I say light enough to be portable without getting a hernia but still be strong and stable.
I am in the process of building a portable 4x6 layout. For portability reasons, I chose 1/4" plywood with 2" blue foam. Homasote was chosen for the roadbed because some - perhaps eventually all - of the track will be handlaid.
I’m not entirely happy with my choice for 2 reasons.
Foam dents easily, and I’m not easy on my layouts. I tend to lean on them occasionally when I’m building, and I’m used to setting my tools on the layout while I’m working, including hot glue guns and soldering irons (tips not touching the surface). [:O] The Homasote will take the abuse, the foam will not.
Foam is not as easy to create grades with as cookie cutter plywood and Homasote. The thickness of the foam works against me where 1 track is over another in parallel or shallow angle configurations.
But this is a learning layout to try new techniques and methods.
I have tried Homasote substitutes in the past (Upson board and Celotex). None worked quite as well as Homasote for my purposes. This time around, I used the dealer locator (calling first), and went 35 miles to get real Homasote.
Homasote is a compressed paper product and was used for insulation of walls many years ago. It is very stable(as long as you do not soak it with water). It is still used for sound control. It is dense and holds track spikes quite well. The bad news is that it is sometimes hard to find, and makes a big mess when cutting it. Other products like Stedi-R/Built-Rite/ceiling tile have a habit of delaminating and falling apart. I have seen several layouts built with the above products and pieces of scenery came loose with a 1/8" piece of the material attached. Most of this stuff does not take track spikes well, and glued tracks tend to break loose as the material delaminates.
I have used 1/2" plywood on my current layout, with Homabed roadbed on top of that for the mainline. The roadbed is glued down, and the track is spiked to the roadbed. After 23 years, I have had no problems. Our club layout is built on foam and has held up well over the past 5 years. The benchwork is dimensional lumber with 3/16" plywood. The foam is glued to the plywood(and each other foam section) using PL300 glue. We used cork roadbed and Atlas flex - glued down with a water base contact cement.
CR&T’s ‘room-prep’ is nearly complete, and the coming benchwork will not be solely from a base of foam. My past experience with either homasote, or plywood, has been positive. Foam when used, will be over some rock-solid base, as it would be just my luck, for a weight-bearing slip through the foam.
For example, some of the layout’s communities will employ ‘cookie-cutter’ from plywood, and; the traction poles especially need something quite solid to withstand (or balance) the tension of live overhead wire soldering.
Why would one put foam over plywood? That negates the primary benefit of foam.
Modelers started using foam to make portable modules so they could connect them to other modules. For that, light weight was very desirable, and foam is much lighter than plywood. The inability of foam to bend was not a particular disadvantage because tracks on the modules had to be at the same level so they could connect.
So, when one uses foam on plywood, one loses the advantage of lightness but is still limited by the foam’s inability to change track levels.
Cookie-cutter and strip plywood permit grade changes and produce useful vertical curves. Plywood’s relative thinness allows under-track access and solid points for attaching switch machines. Homasote also has flexibility, so readily conforms to the changes in the plywood’s elevations. It is a good sound absorber and is an ideal medium for spikes if one uses them.
While many people find it unnecessary, painting Homasote with a cheap latex paint will seal it sufficiently from moisture.
There are some great reasons for putting foam over at least a sheet of luan plywood…
First off having the luan underneath does seem to give it a lot of support without it adding the weight that using 1/2" or heavy plywood would contribute.
Plus it offers the ability of being able to easily attach under-the-table switch machines.
Now as far as the weakness of using Styrofoam, I think the Woodland Scenic’s risers are terrific:
Foam is so versitale its unbelieveable. A rag tag club I belong to, years ago before foam was popular, decided to make a portable layout of foam. Its dimensions were 5’x10’ and with the exception of the legs was made entirely of foam. most of our members are of retirement age and hauling a layout of that size to shows made the conventional way was out of the question. here is the kicker, the framework was also made of pink foam. we had 2"x4x8 sheets ripped into 2x4’s to construct the frame work, over that we put solid foam. and on that we put the risers, track, scenery etc. if any of you in the pacific northwest went to the equifriends swapmeet and show in monroe in the early to mid 2000’s, you probably saw our layout. When I get home from alaska I will have to dig through my photos of the layout build in progress…
I used foam over wooden benchwork. Portions of my layout are now more than 10 years old and I have had no problems. Foam’s advantages are: light weight, reasonable cost, easy to cut with no mess, and it’s unaffected by moisture. I also prefer the use of foam over hardshell for scenery. Wouldn’t you know, just last week I had a plumbing leak directly over the layout. No damage was done (no scenery there yet), but I’d be rebuilding that section right now if I’d used Homasote.
The disadvantages of foam are made clear by other posters: can’t bend, won’t hold spikes, can dent when you lean on it, not as strong, etc… In my experience, the best choice depends on the situation. My layout is an around-the-wall shelf type design, never more than 30’ or so deep. I can easily reach in to the back of any scene and there is no way it will ever need to take my full weight. I’d recommend foam for this type of situation, and for anything meant to be portable. If you plan to use commercial track on cork roadbed, you can lay this right on the foam wherever the track is meant to be ‘flat’. (I found my foam boards weren’t perfectly flat, and in some spots I had to either shave down or shim up a bit, but where the curvature was very gradual it yielded a nice, slight undulation much like what you normally see on the protototype.) In my hidden staging yards I saved the cost of the roadbed and glued the track straight to the foam (don’t do this if you don’t want to hear the trains, though).
I used plywood for my helixes, and would recommend it also for any grade, or at least the transitions into/out of grades. Simply glue the foam board in place, mark the track centerline on it, cut out the section where the grade will be and replace it with plywood. Don’t use foam anywhere you will need to lean heavily or climb on the layout, or if you want to handlay your track. &n
