I am going to build a new layout and was thinking of just laying track on cork roadbed placed on half inch plywood. Then I realized the might not meet my desired goal of zero movement from humidity.
Althought my new space does not have terrific swings of humidity, it will vary a bit and I don’t want the new layout to have the great shrinkage that my medium density particle board (MDF) had.
Most of the layout will be a shelf style about 24 inches wide with Ls at the ends. I haven’t planned a lot of an elevation change (I understand foam can be hard to match up in that use).
I can see that here have been great debates about what to use.
Let’s just say that I can’t get Homosote.
Without opening a can or worms or rehashing a lot, do I just lay the foam on the plywood so that it “floats” rather than fixing it down in some fashion?
Will the foam be too loud?
Thanks for any tips or direction to a succinct thread.
I constructed my layout by screwing 1/2 inch plywood onto a 2x4 frame. Instead of foam board, I simply laid Woodland Scenics Track-Bed and put the track on top of that base. The WS Track-bed is 5mm thick.
This approach resulted in a smooth and quiet base for operations. No warping. I would imagine that cork would produce similar results.
Others will argue that the foam base will permit you to create undulations in the topography but I didn’t care about that since I model the Midwest where everthing is flat.
I made a lot of efforts to achieve a stable system from humidity changes, including using metal building studs for benchwork construction. Mine was in our basement of our 180 year old New England home, complete with granite block walls. For those that don’t know, granite block walls all leak a little water, so the humidity is an issue.
Here’s a sample of what I put together as a test section.
You’ll see in this case I used wooden “bases” as wood does not swell along it’s length.
The system seems to have worked pretty well over the past year or more with minimal movement. However I have wondered if all the effort was truly necessary.
Most modelers simply put in a slight gap, and or seem to treat their plywood with paint or sealer before putting down any track work .I think those two simpler methods would have probably resulted in similar results from my test.
I have a similar situation. My layout is in an exterior shed that has insultion and heat for the winter, but no A/C or humidity control. I chose foam as my base for its dimensional stability, among other things.
“Floating” implies the potential for movement at some point in the future, which could be devastating. Since I know that good ol’ Mr. Murphy looks for every opportunity to invoke his law, I would advise gluing the foam down with latex caulk. It may also help dampen the vibrations.
Also from my experience, I had lots of loose wood in my shed for a humid Michigan summer and a wet winter before the insulation and heat went in. None of my 1x4s turned into hockey sticks, and the plywood remained flat. Some of my thinner masonite warped slightly, but it was not affixed to any structure.
This is a judgement call. To read some previous posts on this subject, you’d think that hearing protection is required on layouts with extruded foam sub-roadbed [:)]. On my layout, I have a section of foam-over-plywood which transitions to another section with foam directly on 1x4 open grid. The open grid foam is not caulked down yet. I set up some test track on cork, also not caulked down, to see what the noise is really like. I found an appreciable increase in noise when the train went from foam-over-plywood to foam-on-open-grid. Though I did not feel I needed hearing protection, it was enough of an increase to make me stop and think about my approach on that section, even knowing that caulk will help. I’m still thinking.
If you have track and trains to play with, I would do
I used 1/2 plywood and 2 inch thick foam held down with cheap latex caulk. I then used cork roadbed for the rails. It is very quite and has held up well in my garage for 2 plus years now.
A tip I all wise pass on. When buying the foam see if you can find a damaged section. At home depot I normally get 75% off.
I use carpenter’s glue ($10.00 a gallon) to glue mine to the plywood. I tried the caulk and found in order to glue the whole sheet of the foam down I used too much caulk ( I Love caulk for track though). I do know a lot of guys swear by it though. I also used the glue for each layer of form - I have two 2" sheets stacked on the whole layout.
I have had no noise issues as far as I am concerned.
Depending on where you live foam can be very expensive and hard to find. My foam from the only source - 1 hour drive away - cost $28.00 a sheet for a 2’ x 8’
Whether something is too loud is a judgement call. For maximizing sound deadening, the general consensus is that the harder a substance dries, the more sound it transmits. Substances such as construction adhesives and white or yellow glue mixtures tend to be less favored now than latex caulk. Caulk is favored by some for other reasons as well.
Also, sound can be transmitted by how the track is ballasted. Again, some people advocate using matte medium/modgepodge solution rather than the diluted white glue mixture since it remains somewhat pliable even when completly dry.
I used foam over an open gridwork of wood for my layout glued down with white glue. I found the noise of the train running directly on the foam to really be nominal, but the finalized roadbed to go in will either be foam or cork on top of the blue {or pink in your area} foam, muting it further. I was opting for the new Woodland Scenics foam road bed and sheets of craft foam, and bought lots, but what I have read about it vs cork think I will make the permenant roadbed out of cork. {SInce I can’t make up my mind yet, I have not finalized the roadbed beyond pinning it down with pins}.
I have a climate controlled room it is in, and along with the rest of the house it is dehumidified by a dehumidifier {about $165 nowadays-maybe less on sale} which is a small {I would think?} price to pay for some reduction in humidity. Just remember to empty the bucket frequently!! The space also has access to A/C’d airflow which affords more drier air also.
You are not the first, nor will you be the last, to complain about humidity around a layout. WHat I don’t understand is that excessive humidity, moderate humidity or even light humidity can be controlled by a dehumidifier- a machine that works wonders at wringing moisture out of the air. A simple easy fix as long as you remember to empty the bucket as frequently as it needs it. ANd they only cost around $165 +/- - the price of a new locomotive. We live in a trailer and use a dehumidifier to keep humidity down between heating season and A/C season and A/C season and heating season… It works very well and keeps my Layout working well.
Along the long axis of the tree? I’ve never seen wood expand along the vertical dimension (through the grain). I’ve never had an 8 foot 1x6 grow to longer than 8 feet, for instance, or shrink under it, although both the 1 & 6" dimensions show fluctuation.
I have 2 layers of 2" foam on top of 1/4" plywood. Carpenter’s glue works quite well for attaching the foam to the plywood and the second foam sheet to the first one. Do leave sufficient time for drying - with little ability for air to penetrate, it does take a while, especially if it’s humid. Caulk is great for the track and roadbed, but yes, it uses too much to attach a sheet of foam to a sheet of plywood to be economical. I used only 1 tube for ALL the track and roadbed of an 8x12 layout - for one 2x8 foot section of foam it took almost an entire tube.
Having some old bench work with 1/8th. inch plywood I continued this with my new sections but added foam on top. The local stores only had 3/4 inch in 4 X 8s so I layered one on top of the other. I used latex caulk running a bead around the perimeter of each sheet and then a diagonal bead from corner to corner with excellent results.
The foam really paid off when I started installing Peco switch machines as they fit directly under the turnout. So it was easy to “excavate” a hole in the foam for the machine.
As has been said it also makes it easy to plant trees, create water effects, etc.
Thanks for that link. I’ll admit the numbers are bit hard for me to sort out - but If I read this correctly, this is changes due to Thermal influence, not humidity (although I understand they can be related), and smaller numbers are better?
I’m guessing you may have an engineering background (I certainly don’t!) Could you help elaborate?
I’d be pleased to correct a misunderstanding I may have
Yes, that link relates to thermal influence and smaller numbers are better. In the presence of moisture wood does indeed expand mostly across the grain, but also somewhat with the grain. The degree of movement under both influences depends on species, type of cut, environmental conditions, methods of fastening, etc.
For an example of a practical application where the amount of movement can be significant because of the size of the wood installation, a traditional gym floor comprised of strip hardwood lumber is laid with a wide gap all around the floor to allow for the movement of the strips/planks in both directions. This gap, which might be 3/4"-1", is then covered with a floor/wall base that has a wide “toe.”
Since I’m modeling an area where the scenery stands on edge, the widest ‘cookie’ in my cookie-cut plywood subgrade is about 18 inches, and most is much narrower. The plywood is 3/8 inch, supported about every 16" by risers from the ‘C acts like L’ girder-supported benchwork. Girders, joists and risers are steel stud material. I have also laid hidden track tangents in L girders positioned like rain gutters - I can get away with supporting them somewhere close to each end.
Above the subgrade, whether plywood or the bottoms of steel stud ‘rain gutters’, goes a layer of fan-fold underlayment - a thin extruded foam product used by professional siding installers under metal or vinyl siding. That is attached with a THIN coat of latex caulk. Next I caulk a full-scale track template, made of card stock sealed with grey paint, to the upper side of the thin foam. Finally, I caulk down the flex track, and the wood ties for my hand-laid specialwork with grey caulk.
I can hear the screams now - You Can’t Spike Into Foam!!! Well, for three years now I’ve been running over hand-laid specialwork laid on wood ties over cardstock over foam, with two layers of vinyl caulk between. The cardstock provides lateral stability, while the cured caulk seems to grab the spikes and hang on - they are not easy to pull if revisions are necessary.
Ballast contours are carved into the foam layer before it goes down, in places where track will be visible. Where the track is hidden I don’t bother.
This might not work for everyone - track nails WON’T hold - but it has been working for me.
That makes sense to me on one level, but not from a practical standpoint, at least from my own observations.
I just put in a laminate floor where we did that, but I presumed it was due to the composite material used. I truthfully can’t remember the last time I put in a hardwood floor, that was about 5 years ago.
When I’ve framed new walls, we haven’t left space. I wonder if that’s just getting locked into space by the building weight, or if they do bow a bit on the inside from fluctuation? Not enough fire blocks to make a difference, I guess.
Thanks for your information, and there’s probably no need to keep mucking up this thread. You don’t need to reply, but if you do, perhaps a PM might be more appropriate.
