I've used the foam on my home

Only downside I have seen..

The only time where I have seen this become an issue is when used for modules. The Frame and foam after time began to separate and it sagged between supports. This was after it made many many many trips.

I have also worked with foam and the only things I did not like was trying to drop feeders or turnout controls with the added depth. If I had some foresight and a longer drill bit it probably would not have been an issue.

I created two modules made

I created two modules made out of hollow core doors with extruded foam glued to it in January. I put a valance of 3'4 inch plywood on it flush to the height of the foam, which now I realize is overkill, but they are solid and don't twist. I used only 1 inch foam because I'm only making some ditches and didn't want the terrain completely flat. The modules are heavier than I expected, but they will not be traveling to hobby shows. The modules are ready to have track laid, but have been busy with other things. 

I glued a homasote roadbed to the foam.

I would use at least glue a thin sheet of plywood to the bottom of the foam. 

If you like, I can post some photos of the modules that someday will be integrated into a future layout; hopefully this fall.

Noise Suppression

There has been a lot of discussion on various Yahoo groups, including the HOn3 group and the Layout Construction group on foam usage. Basically you can suppress the booming noise generated by 2 inch foam by gluing to its bottom 3/16 inch tempered hardboard like Masonite. While most of my still building layout uses spline with Homosote on top, either 1/2 inch Homosote or 1/4 inch California Roadbed ("Homabed"), I do have some newer sections with foam, either 1" or 2". Those foam sections under which the Masonite has been glued are quiet. Foam sections without the Masonite underlayment are very noisy. However, nothing to my ears is as quiet as Homosote over 3/4 inch plywood.

Note that it is not the use of cork on top of foam which suppresses noise; rather the noise is generated by the foam itself unless it is kept from vibrating by the Masonite underlayment.

Note also that the best way to adhere the Masonite to the foam is with a foam friendly glue like Liquid Nails--I use the heavy duty "904" version of Liquid Nails. (I think "904" is the number designation.) I believe products like DAP 230 Dyneflex adhesive caulk, which I use for gluing track to Homosote, would work well also. But you will need a lot of the adhesive, whether caulk or Liquid Nails. Do not use yellow or white glue as these dry hard and are themselves noise transmitters.

John

"sculpt the land forms"

   If you use 2 inch sheet foam you can only sculpt less than 2 inches or you will go thru it so you still need something underneath, either more foam if you want to dig deeper or a base of plywood if you want to stop at 2 inches deep. I don't worry about the sound transmission of foam  as I like trains to make noises but I don't like installing switch machines or Blue point controllers thru an extra 2 inches of foam so I'd still glue wooden roadbed over the foam and then cut away the foam in the areas around the switches which might be more work than just building wooden benchwork with wooden roadbed and adding foam where I want scenery :> ) ?? .DaveBranum

Mountain Goat Greg, Another

Mountain Goat Greg,

Another downside I read is that over time, the foam will shrink a tad all pull away from the ends of the module causing a ski slope effect near the ends of the module, but a piece of floating track will solve the problem of track warping or buckling at the ends. Also putting a piece of wood under the roadbed near the ends will prevent the ski slope effect.

I'm told not to press hard when cleaning your track because over time it will cause slight depressing in the foam.

Though noise is not a concern

Though noise is not a concern for me running trains John, I will attest that using homasote on plywood is very quiet. I've done this in the past and my trains ran very quiet even the brass locos. My next layout will have homasote roadbed glued to plywood except for the modules I mention that will be integrated into it.

I am using foam...

for my 2' x 8' shelf layout. You can see my blog on the layout starting with shelf construction here

For me the foam was great. I have had no real sound issues. There are two 1x2 L girders running the length of the layout (glued to the bottom of the foam) because I was concerned about the foam being brittle. I do have cork and Homasote as roadbed and that might help too. I have used plywood and Homasote in previous layouts and don't think this one is any noisier than the others.

I think the benchwork you show in another thread and cork roadbed would keep sound from being a big issue. I would also refer you to George Booth's layout making extensive use of 2" foam for subroadbed.

I say "Go forth and build"!

Forget the pllywood,

A 2" foam base is all you will need, do not skimp on the cross pieces, I used the yellow carpenters glue to glue the foam to the frame and cross pieces as well as to glue the edges of the foam together where they abut.

I have a u shaped 8' x 12' and used 3/4" plywood, and the result is over kill,

I used additional foam panels to build up my elevations and unless you intend to be standing on the layout you do not need the plywood.

Actually, not using the plywood is a noticeable monetary savings.

A side note, one of the neighbours who is also a model railroader recently decided to build a new layout and he had not used the plywood.  It was very easy to dismantle the layout. A very sharp long kitchen knife slidinjg the knife between the top of the wood frame and the foam and the layout was no longer connected to the table.

Had someone wanted the layout they could have easily put it together on a new frame.

If I had someplace to store it I think i would have taken it. Was quite a nice plan. Could have used it as a door prize at the local MR club annual sale.

I have been using Foam since the mid 1990's

Now my benchwork is metal studs, which i have been using since 1993, but never was satisfied with any of the wood products/methods, and I tried most of them.  The I atteneded a regional NMRA Convention in the mid 1990's and Keith Thompson (when he worked for MR) came and did a clinic on it.  i had read Bill Darnaby's article on using foam, but after watching Keith's clinic and demo, I was sold on  it, and have been using it on my model railroad projects ever since.

For a base, I have used 2", 1", and even 3/4" FoamUlar Insulation Foam, and never have had issues. 

I mostly use the 2" boards, cut them into 2" x 2" x 8' long strips, notch them so they can be made flexible, then using a cutting jig and a bandsaw blade, but them to the appropriate grade (1%, 2% or 4%) that I want.

Much cheaper than buying the WS products.

This is the same thing we are doing on the local model railroad club's O Scale Layout I am involved with, and everyone so far is pleased with the results.  The Benchwork is 2x2 Metal Studs spaces 2' on center, with "track" pieces on both the front and the back so all four edges have something to glue too, which prevents any possibility of sagging.  

Ken L

You Asked for It

My opinion will be contrary to most here, but i despise working with foam for roadbed or scenery.  Give me something truly solid like spline or plywood and let me build up scenic contours instead of carving them from a block of material.  And keep me away from that awful squishy Woodland Scenics foam roadbed while you're at it.

I will agree with Rob on one thing..

...stay away form the Woodland Scenics products, PERIOD!

I forgot to mention I am using FlexxBed from Hobby Innovations.  I also am using up my supply of Vinylbed, which I find better to the Flexxbaed, but i am assured by the manufacturer the Flexxbed is superior to the Vinylbed.  I sure hope so with what I invested in there new product LOL!

The Flexxbed with isolate any sound vibrations, so the issue of it being noisy becomes moot if you use flesssbed.  Plus, a bonus is it comes in different thicknesses and they have different roadbed profiles to offer as well.

Ken L

Inclines?

It seems to me grade changes would be a sloppy matter unless you buy the WS risers and then you are constrained. Can't imagine the mess you would make when trying to plane foam for a gentle grade.

I am going to use foam for scenery purposes in my flat land areas and hardshell in the mountains just as I am using ply for subroadbed in some areas and spline in others. Whatever is best suited for the spot.

The noise issue comes up a lot so there must be something significant to it.

I Used the 2" Foam...

...glued to 1/2" plywood, which is screwed into the bench frame. The ply really firms up the framework so it doesn't shake, even when accidentally bumped into. I don't feel uncomfortable putting my weight on it. The foam is glued using WS Foam Tack. I also used the WS foam roadbed. I guess some folks think it is not as realistic looking, but you will probably ballast it anyway. It is extremely easy to work with, right off the roll, and makes it a snap to follow the curves and work around switches. I have worked with cork and find this stuff to be much easier. I don't like all of their products but I've been satisfied with most of them.

You are getting various opinions Rick. Confusing, isn't it?

It's not that hard.

Using a table saw and band saw, and a homemade jig out of plywood, making the incline pieces is a sinch.

As for the noise issue, as I said, if you lay the track on a good roadbed, such as Flexxbed, the issue doesn't exist at all.  if you lay track directly onto the foam, then yes, there can be some additional noise.

Ken L  

No inclines

"a couple of things?"

    Will there be scenery that drops below the track more than 2 inches?  That seems like the thing that would determine if all foam was the way to go. If the scenery is all level or going up above track level then foam would be easier to use, any deeper drops are going to require something below the foam sheet. If the layout is fairly level then it might be ok with 2 inch foam but I'd still cut out and glue plywood roadbed over the foam where turnouts are located so  they would have a thin strong base to mount switch machines or throws..DaveBranum

Foam base and inclines

Foam base and inclines

...

I have no issues using it - and I always put cork under my track.  If it's a large area, I'll use sheet cork so you don;t have the roadbed profile.

This literally is one of those things you have to just go do and find out how you like it and how it works out for you.  I say this because if I had listened to all the people talking on the internet, I never would have got a single one of my layouts half built - and every one has at least got to the "applied power and ran a couple trains" stage.

When you have foam under the cork, you can use long sewing straight pins to secure down your track.  If you want to move it, take the layout apart in section, either follow what MJ does with gorilla glue and pcb ties, or remove the section of the track over the joint by puling up the straight pins and pulling the piece.  It's that easy [hence why I don't use caulk to hold down my rails!]

I did 3" of blue foam....

Pro foam

I installed a 2" x 2' x 12' extruded foam section on my old layout and was pleased with it. 

I put it on top of a simple wood frame without adhesive or fasteners.  I used 2" x 2"  supports spaced every two feet - again without glue or fasteners (wanted to be able to move supports in case I changed the design).  No problem with stability, and no problem with noise - ran maybe two trains at a time over it.  It was in my garage and subject to temp and humidity variations.

I punched feeder holes with a wood awl.  I cut drainage ditches with a sharp knife, or used a hot knife, or used a hot wire tool (with adequate ventilation).  Switch machines required extra work.  I used a thin piece of hardboard to provide stability.

For hills and other features I used thinner pieces of foam, which I hot glued in place.  I had to use plaster cloth for landscaping to give some tooth to the slick foam.  I found, however, that Sculptamold took a long time to dry due to the slick, nonporous surface (a fan helped it dry faster).

I tore out my old layout, but saved all the big foam pieces for reuse on my new layout.  Some pieces I left outside exposed to the weather for a year.  Other than being dirty, they are good as new. So I think foam would be great if you ever need to move your modular sections.

Go for it!

David B - a couple of things

Dave,

I will have one section with a trestle where the landscape will drop below 2" of track level; however, that section of benchwork will be designed with that drop as part of the design.  Since in HO scale 2" equal roughly 14-1/2 feet I don't believe that I will have more than that as a cut / drop.  If I use foam I do plan on using reinforcement for turnouts and turnout machines (if used).  Thanks for your input!

Thanks, Dennis

Thanks for sharing your constructions method using foam.  I would be interested in seeing a photo.