Questions about foam board

[shark_jj]

It has been almost a year since I did any work on the Grand Trunk Southern and have spent that time foraying into HO with a 20X40 modular layout.  I seriously considered switching back to HO given my age (65) and the eyesight and slight tremble in the hands issues that age brings, however, after a lot of soul searching, I simply like the mainline opportunites that N Scale offers too much to give it up.  In any event, I fortunately did not tear down any of the benchwork that was the beginnings of the GTS.  I am now getting back to concentrating on getting this layout up and running.  One of the things I am considering is using foamboard as an underlay for my track.  The benchwork is 24 inches wide, cantilevered off the wall, using a box grid framework.  I currently have 3/4 inch plywood on top of the framework.  I am currently using pieces from the previous layout and it is very much a patchwork which is dissatisfying to me as well as causing issues with Tortoise installations falling on joints.

For town and yard areas I am considering going to dominoes.  Modules that will be permanently installed on the box grid framework.  The modular construction would allow me to sit at a workbench with a four foot section and do the trackwork, wiring, tortoise installation, etc., without contorting my body in too many different directions.  I could construct these modules using a standard 3/4 inch plywood on top of a grid type of construction, but in looking at articles by Lance Mindheim, and Jim Six (he used ceiling tiles as an underlay), I am quite taken by how easy it becomes to create slightly elevated mainlines and scenic variations (in height) by using foamboard. 

I am considering using a combination.  Either 1/4", 3/8", or 1/2" plywood as the main base under areas which have track.  This would simplify tortoise installation.  On top of that 1" pink foamboard (13 feet in N Scale).  The two laminated together would be more than solid. 

I know that many of you have used foamboard, so my questions are:

1:  Any suggestions on the appropriate thickness of plywood for the bottom layer.
2:  I considered the 2" foamboard but settled on the 1" under the track since it is easy to build up elevated areas, and the 1" foamboard plus even 1/2" plywood is only 1 1/2 inches to run the wires up from the tortoises.  Your thoughts on that approach.
3: The most common complaint about foamboard is that trains are noisier.  Personally I find that most N Scale engines run very quietly so a little noise might be a good thing.  Can anybody quantify for me what "noisier" means.  Does it reach the annoying level?

Thanks for any insights you are able to share.............John

[diezmon]

I've played around with foam with and without a base under it. 


1.  Sounds like you're not dealing with huge spans anywhere, so I'd think some good quality 1/2" would be sufficient.

2.  1" seems fine.. unless you need cuts, or areas that will dip further below the track?    A thinner profile is easier too if you plan on using tortoise machines..

3. You'd think 2" foam in smaller spans would be ok. but it's LOUD.   If nothing else, the ply helps take some of that noise away.  Take it from me.. the noise will start to drive you a little insane and you'll wish you'd gone with wood underneath.      "noisier" means.. you'll hear the wheel noise.  It's not the motor noise.. the sound of the trains along the track.   Foam alone tends to amplify this. 

There have been many posts, and articles on noise suppression.. but I like to keep to the K.I.S.S method.. foam on wood, it's good.   oh cool, I made a rhyme. 

[Bendtracker1]

I've taken a little different approach.
I used 1/2" plywood with a layer of 1-1/2" White bead board foam, then used a layer of ceiling tile on top.
Since my turnouts are all manual, I wasn't too worried about the thickness.  I used the 1-1/2" and Ceiling tile so I could carve them out below track level.  Even just one or maybe two layers of ceiling tile would work fine on 1/2" plywood.
I used PL-200 to glue things together.
The ceiling tile does a great job of keeping the noise down and it's easy to shape like the foam.

[mmagliaro]

First, I agree with you completely about the ease of making more realistic terrain by using foam board.
I built a small 4x8 "test layout" on it, and I was convinced.  I have built my current project on 2" foamboard over an open grid of 1x4's.   They are spaced 16" on center, so the largets possible area of foam that has to support itself is a 16x16 square.  I have not had the slightest problem with deflection or sagging in the 18 months it has been up.

I would not trust 1" foam over an open grid unless it were braced so much that it would be arduous (like, maybe every 9" ?)

So, your plan to put 1" over plywood sounds fine to me. 

To your questions. 

No way would I use 1/4" plywood.  I have had too many bad experiences with 1/4", even when it is braced a lot from underneath.  It just doesn't quite keep from sagging or heaving up, and even a little bit is
a big annoyance.   I would go with 1/2", not even 3/8".  You only want to do this once, and you don't want to discover a year from now that there is some unexplainable dip in the surface.

Whether you use 2" or 1" foam is really a matter of what you plan to do with your terrain.   If you want to put in a deep cut or some ground that slopes down away from the track a good bit, or maybe a water feature, I think it would be easier with 2", and allow you more flexibility with what you can do.  The trade-off, of course, is running wiring up through all that foam and getting the Tortoise links through there.
Personally, I'm glad I have 2", because when you start hacking away with a rasp or knife,  I don't know, 1" doesn't give all that much depth or relief.

As for noise... I have heard complaints about noise on foam, but I don't hear it.   I have 2" over an open wood grid, so it should be the noisiest of all possible "drumheads" you can imagine.  But if I walk out of the train room and down the hall about 10 feet, you cannot even hear that the trains are running.
My entire room is carpeted, so maybe that deadens the sound.  I don't know.

Anyway, in my experience, I have no complaints about the noise.  It's the same or less than I had
with cork on plywood, or WS foam on plywood, on previous efforts.

[shark_jj]

Thanks guys, this is all good information.  I only plan on doing this in areas which are scenically flat, i.e. yards and towns.  The foamboard would allow for the types of minor variances that you see in those areas, particularly a slight raising of the mainline through the yard.  I was interested in the comment about the ceiling tiles since I read Jim Six's article in GMR pr MRP (I can't remember which) in which he used ceiling tiles and laid track right on it, it has fascinated me as an option.  Put the mainline on cork and the yard right on the ceiling tile.  Since it is more dense than foamboard I suspect that the noise would be less.  The noise question seems very much to be in the ear of the beholder. 

[rogergperkins]

I do not think you are asking about "foam board" which is a product used as a backing for mounting poster or pictures. "Standard foam board is a versatile, all-around graphic and display board with memory. This foam board consists of resilient extruded polystyrene core sandwiched between two layers of bleached, semi-gloss white clay coated paper. Ideal for screen printing, die cutting, mounting, framing and prototypes."

I had a n-scale layout which was 1/2 inch plywood and Kato unitrack directly on the plywood.  About 7 years ago when I rebuilt, I added 2 inch pink extruded polystyrene on top of the 1/2 inch plywood.  This is very sturdy, more than is probably needed for n-scale especially since I also use the 2 inch pink extruded polystyrene laminated to create hills, so very light compared to other options.
I have read published articles that the 2 inch pink or other extruded polystyrene could be used with periodic one x two inch cross supports instead of plywood.  I know the 2 inch pink extruded polystyrene is sufficiently sturdy without any underlayment because I have several area where it extends eight inches beyond the plywood.

[diezmon]

"foam board" 

- "you keep using that word.  I do not think it means what you think it means"   

[DKS]

As for noise... I have heard complaints about noise on foam, but I don't hear it.

Foam insulation panels can be very noisy; they act as a sounding board, and can even amplify sound. Unfortunately, many modelers assume this is true under all circumstances, and thus unfairly give the material an bad reputation. Thing is, you will find that as you add scenery and other maretials, noise will diminish very quickly, to the point that it's comparable to most any other construction method.

[LV LOU]

First, I agree with you completely about the ease of making more realistic terrain by using foam board.
I built a small 4x8 "test layout" on it, and I was convinced.  I have built my current project on 2" foamboard over an open grid of 1x4's.   They are spaced 16" on center, so the largets possible area of foam that has to support itself is a 16x16 square.  I have not had the slightest problem with deflection or sagging in the 18 months it has been up.

I would not trust 1" foam over an open grid unless it were braced so much that it would be arduous (like, maybe every 9" ?)

So, your plan to put 1" over plywood sounds fine to me. 

To your questions. 

No way would I use 1/4" plywood.  I have had too many bad experiences with 1/4", even when it is braced a lot from underneath.  It just doesn't quite keep from sagging or heaving up, and even a little bit is
a big annoyance.   I would go with 1/2", not even 3/8".  You only want to do this once, and you don't want to discover a year from now that there is some unexplainable dip in the surface.

Whether you use 2" or 1" foam is really a matter of what you plan to do with your terrain.   If you want to put in a deep cut or some ground that slopes down away from the track a good bit, or maybe a water feature, I think it would be easier with 2", and allow you more flexibility with what you can do.  The trade-off, of course, is running wiring up through all that foam and getting the Tortoise links through there.
Personally, I'm glad I have 2", because when you start hacking away with a rasp or knife,  I don't know, 1" doesn't give all that much depth or relief.

As for noise... I have heard complaints about noise on foam, but I don't hear it.   I have 2" over an open wood grid, so it should be the noisiest of all possible "drumheads" you can imagine.  But if I walk out of the train room and down the hall about 10 feet, you cannot even hear that the trains are running.
My entire room is carpeted, so maybe that deadens the sound.  I don't know.

Anyway, in my experience, I have no complaints about the noise.  It's the same or less than I had
with cork on plywood, or WS foam on plywood, on previous efforts.

I'm on my third foam RR.I pretty much do exactly what Max does,and pretty much would follow exactly what he recommends,although I also think the plywood is not necessary..As long as you keep it at 16" on center,there are no problems.My last RR was ten years old when I dismantled it,it was still dead flat,and I used to climb up on it,and I'm a big boy..I run all MTL plastic wheels on my RR,the train are very quiet.One thing that will really quiet it down,put a full cloth skirt around the whole thing..

[Bendtracker1]

  I was interested in the comment about the ceiling tiles....  Put the mainline on cork and the yard right on the ceiling tile.

Here's a couple of shots where I did just that;
The mains and A/D tracks are on cork and the yard is on the ceiling tile.




The sections where the vertical transition takes place, I just glue that section of cork down and then took a block of wood with 80grit sandpaper attached to it [see them in the middle left of the top picture] and after it was dried, I just sanded the cork to a nice even decline to the tile.  I've also seen where some guys have cut out the ceiling tile or foam to a depth equal of the cork and laid the cork down into the groove.

[DKS]

I'm on my third foam RR.I pretty much do exactly what Max does,and pretty much would follow exactly what he recommends,although I also think the plywood is not necessary..As long as you keep it at 16" on center,there are no problems.My last RR was ten years old when I dismantled it,it was still dead flat,and I used to climb up on it,and I'm a big boy..I run all MTL plastic wheels on my RR,the train are very quiet.One thing that will really quiet it down,put a full cloth skirt around the whole thing..

Agree that the plywood is unnecessary. The White River and Northern IV was just 2" foam glued to a 1x2 wood frame that was screwed to shelf brackets.

[mmagliaro]

Guilty as charged...   It's not "foam board".  It is  "Rigid Extruded Polystyrene Foam Insulation".
Foam board is .... I don't know what it is.

[Denver Road Doug]

Here's my take on the foam idea.  Completely foam, 1" layer laminated on top of 2" and sitting on wooden-ish shelving.  Plenty of strength.



Here's a better view of the cake layers.   I recessed the 2" a bit just for looks.

[DKS]

Foam board is .... I don't know what it is.

I think this can be taken as meaning Foamcore, which is a paper/foam/paper sandwich.

[LV LOU]

By the way,when doing multiple levels,2" is perfect for the second level,even autoracks will fit under the bridges..