Layout Foundation Construction

mightypurdue22 Jul 28, 2015

  1. mightypurdue22

    mightypurdue22 TrainBoard Member

    I'll be building a new layout in the coming months, as we are moving to a different home. Of course my mind goes directly toward building the layout instead of stripping wallpaper and all that fun stuff. I'll be using extruded foam as a base and would like to essentially do 2.5-3" of foam. My idea is to not do total depth foam, but instead use 1/2" foam layout top with 2-2.5" tall spacers. This leaves a void beneath the 1/2" foam and reduces cost and the amount of carving needed to develop grade changes below track level. Below is a preliminary cross section of what I'm thinking about doing. I have access to Gatorfoam spacers for free, and will glue the 1/2" foam topper to the spacers with liquid nails.

    Knowing there are many ways to build the foundation for the layout, does anyone see any pitfalls that could make this construction method troublesome? I want to say I saw a similar method in Model Railroader, but it also could have simply been on a MR forum. Thanks...

  2. BoxcabE50

    BoxcabE50 HOn30 & N Scales Staff Member TrainBoard Supporter

    How much weight will you be planning to place atop the foam board base? Thinking about adequate support, so it does not sag or warp. Also, it could act somewhat like a drum head and be noisy, if a lot of hollow beneath. Just possibilities to look at first...
  3. mightypurdue22

    mightypurdue22 TrainBoard Member

    It will be N Scale, I'm not overly worried about support. I'll add as many spacers as I should to keep good stability. I'm not certain about the noise factor though, as that's not something I had considered. Food for thought.
  4. RBrodzinsky

    RBrodzinsky Staff Member TrainBoard Supporter

    The three things that immediately came to mind are: strength, sound and scenery options. The first two have already been mentioned, but I wouldn't rule out deeper foam, at least in areas where you might want to carve out some scenery below the track. Think drainage ditches/culverts, small stream with bridges, and even simply rolling ground.

    Also, how do you plan to drop your feeders? You show a plywood base, but feeding your feeders through an open area will be tricky. Even straight down will take a lot of patience. What track? And, unless Unitrack, what about switch machines? All questions just food for thought.
  5. emaley

    emaley TrainBoard Supporter

    I am workinf on a z scale layout right now. It started as a 2' x 4' base with a sheet of 1/4" plywood on the frame and then 3/4" foam. No problem with sound. I decided to enlarge it to 48 x 30. The frame addition did not have the plywood , but was covered with 1" foam. It is now a drum head. Even a tiny z scale loco is enough to make it resonate. I had heard of the issue, but was not a believer. No for my next trick, lol.

  6. mightypurdue22

    mightypurdue22 TrainBoard Member

    Wow, I guess that answers the question about leaving a void space beneath the foam. Thanks for the input.
    polarMike likes this.
  7. BoxcabE50

    BoxcabE50 HOn30 & N Scales Staff Member TrainBoard Supporter

    Yup. That's why I'd earlier mentioned the possibility of noise troubles. :(
  8. tracktoo

    tracktoo TrainBoard Member

    That noise issue is very real. I have a test loop of Z scale track on a 20" diameter drop of 1/2" foam board and when sitting flat on a good table surface it's absolutely stone quiet. Sitting on an irregular surface that just picks up a few points around the perimeter of the board, noisy as could be. I would never have thought it would be that noisy. The drum head analogy is the best way to describe it. You could probably lay some track on a piece of foam to test for your conditions.
    BoxcabE50 likes this.
  9. jdetray

    jdetray TrainBoard Member

    On my small N-scale layout, I am using 3/4-inch blue foam glued to 1/4-inch plywood, and that really helps reduce the noise as described above by Trey. In the photo below, you can see that I use blocks of pink foam to support the elevated branch line.

    - Jeff

  10. Jeepy84

    Jeepy84 TrainBoard Member

    I too agree the noise reverberation will be an issue. The MR plan I believe you are referring to was about module building, not home layout building. Portable modules are best kept light, for obvious reasons, but the sound amplification doesn't matter much, because shows are noisy places to begin with.

    I do however like the idea of saving foam with the voids. Perhaps there is a way to have this cake and eat it too. If you have a track plan, you can layer solid foam where you will have major depressions like creeks and etc. But under towns, yards, and etc, you could have those voids. Filled with crumpled newspaper or some other sound absorbing media. Not sure how effective it might be, but interesting enough to experiment with? For feeders, before filling the voids, you could take a long drill, drill down through the foam and the plywood and then form a conduit from a drinking straw or similar? An added benefit of your voids is you could employ some of them for hidden staging as well.

    Sent from the magical mystery box
  11. jdetray

    jdetray TrainBoard Member

    On my layout (two posts above) I passed feeders through as much as 6 inches of foam and plywood. I found that by using solid-conductor feeders, it was not even necessary to use a conduit to route the feeders. The stiffness of the 22 gauge solid feeders was sufficient.

    When looking online for extra long drill bits, search for aircraft or long boy bits. I also found some long bits from Irwin at Lowes.

    - Jeff
  12. gcav17

    gcav17 TrainBoard Member

    The noise that comes from unsupported foam is almost ridiculous. I have a three foot run coming into Balderdash that is open and 42" from the floor and in a small space. And since I run steam. For some reason it's even louder. The one diesel, ( con cor dl109 ) Is not as loud. So yeah. Thicker foam. Mounted on a plywood base is much better. Plus. You have a ton more scenic options. Long term stability. (Foam does give in to gravity) And more fun being messy.. Haha

    Sent from my SM-G900V using Tapatalk
  13. cajon

    cajon TrainBoard Member

    Here's another version of Styrofoam modules. Saw this on a SoCal layout tour Sept. 2014. This type of module was developed by Dennis Ivison from Garden Grove CA. He used 2" Styrofoam sitting on PVC legs. They are super light but very strong. Dennis told me he has stood on & laid down on them. He uses these modules for an On30 layout based on a fictitious SP narrow gauge RR in central coast of CA. Most of his modules are 30" x 72" to give him alot of room. So there's plenty of scenery & he runs some large steam locos. He's never said anything about the Styrofoam being noisy but then all his locos have sound plus there's alot of scenery like tall trees & structures. Will be using this module concept for my HO layout based on the Los Angeles Junction Ry (LAJ). This RR is all switching plus their maximum authorized speed is 10 MPH. So doubt noise will be much of an issue. But if it becomes a problem have ear plugs. LOL
    1 COMPLETE MODULE IVISON.jpg 2 MODULE PARTS IVISON.jpg 3 Ivison  Module PVC Legs.bmp.jpg

    Attached Files:

    Last edited: Aug 21, 2015
    subwayaz likes this.
  14. Colonel

    Colonel Staff Member TrainBoard Supporter

    I used the traditional method however did consider styrofoam but not readily available here in Australia, for benchwork i do like the styrofoam module concept
  15. robert3985

    robert3985 TrainBoard Member

    I also use traditional methods for my portable layout's benchwork. I've used 2" blue DOW Extruded Styrofoam stuck together with Liquid Nails for two 6' modules/sections, and because the trackwork on those wasn't complex (double tracked mainlines) my wiring wasn't particularly complex even though I run a 22 AWG feeder to every piece of rail on all of my layout.

    At first, I was pretty stoked about how easy extruded Styrofoam is to work with, even though I used my woodworking tools to saw it to the same dimensional tolerances as my traditional w00d benchwork.

    After installing the scenickly unfinished modules into the layout, the first thing I noticed was the HUGE difference in noise as engines and trains traversed the 12' of Styrofoam sections. Whereas trains traveled virtually noiselessly on my splined Masonite subroadbed traditional sections, when they'd come onto the Styrofoam modules, they seemed to be exponentially louder.

    Since the layout is portable and is disassembled and taken to two or three shows a year, I found the joints would break quite often on the Styrofoam modules...not just on the ends, but also the joints between layers of scenery. I started fixing them at shows using a hot-glue gun, which was quick and convenient, but...the joint wasn't as strong as Liquid Nails joints, and would break again either during the show, or when I set up again at home.

    I also found that the modules weren't as dimensionally stable as my wood modules, and after a couple of years, the track buckled because they started to sag...even with as much as five layers of 2" Styrofoam and structural elements underneath. The span between the legs was only 4', with 1' hangovers on either end, but...they still started to sag.

    Sooooo....even though a lot of model railroader swear by using Styrofoam, Gatorboard, Homasote and other less dimensionally stable materials to make their layout benchwork, my decades-long experience with a portable layout is that straight premium pine boards, sanded-both-sides CDX 3/4" and 1/2" plywood, and splined Masonite subroadbed, using L-girder construction with risers holding the subroadbed, joints glued and screwed (yellow carpenter's glue and square-drive grabber screws) is the way to go if you don't want future dimensional problems with what is supporting your track.

    If you live in a really humid climate, I'd go with quality plywood (not something salvaged from a construction site), using straight 2x2 dimensional lumber at the corners for "screw bases", and gusseted and braces 2x2 redwood baluster material as legs...with glides or carriage bolts in T-nuts as feet to get your layout perfectly level, and compensate for uneven floors if you move it.

    Here's a view of my basic L-girder layout construction (made in 6' sections where possible) with the accompanying screw-on skyboard not showing the folding legs:

    Here's a view of classic L-girder benchwork I took from Lynn Wescott's book about making different kinds of benchwork:

    Here's a photo of one of my odd-sized layout sections showing the attached Masonite fascia, Masonite skyboard, legs and plywood end plates (unnecessary for a non portable layout) buckled up to another odd-sized module on the Echo Curve LDE:

    The only drawback to traditional methods I can see is that you have to have basic woodworking tools and know how to create a square joint.

    I use extruded Styrofoam for the scenery base, and I won't use anything else. But, for anything structural, I use wood.

    Bob Gilmore
    chooch.42 and Twist like this.

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