Foam, Cork and Plywood

[taholmes160]

HI Folks:

Hopefully going to start cutting wood and building in the next day or 2, and I have been wondering if cork roadbed on directly on the 1/2 inch plywood or if putting 1 inch of pink foam under it first (allowing me to carve creeks and rivers and other depressions is the way to go.

Ive in my other thread about cork / homosate ive gotten a variety of opinions, and I've decided that Homosate is out for sure, but I'm curious about using foam, and how to secure track if I do?

Thanks
TIM

[Steveruger45]

For my layout I used 7/16” OSB on a 1”x3” (actual 3/4” x 2.1/2”) frame topped with two layers of 3/4” blue foam, all from my local Lowe’s. I faced the frame with 5mm thick Luan meant for flooring underlayment.
Here is a photo.

[taholmes160]

Hey Steve,

That looks awesome -- Do you use motorized switch machines?  if so, do you have any problems with the inch 1/2 thickness and getting the switch actuator wires through?

TIM

[davefoxx]

I went with 1/4" lauan plywood over top of my L-girder frame with 2" foam on top of that.  Cork roadbed is glued to the foam with yellow carpenter's glue, which is also used to glue the track to the cork roadbed.  By using 2" of foam, I can cut out ditches, creeks, and, in my case, a lake, well below the roadbed.  Like DKS, I'll never go back to Homasote over plywood.

DFF

[Steveruger45]

Hi Tim,
I used Kato unitrack on this layout as it’s in a garage in Hot, Humid South East Texas and as such don’t have an issue with electrified switches. 
I do have operating grade crossings powered by tortoise switch motors and they work ok. But having said that I do get your concern with switch motor reach through two inches of wood and foam for a powered track switch.
There are probably switch motors that could work through that much sub base, but I haven’t tried. I have had the tortoise machines work through 3/8” plywood with 1/8” cork sub road bed perfectly fine on a previous switching layout.
An alternative would be to put one layer of foam and cut out the base plywood and mount that to the underside of the frame in places you want scenery deeper below track grade.  Or just “cookie cutter” the plywood for the track areas.  Or a mixture of these.  With these latter approaches you would need more intermediate cross-bracing framing as now the table top of plywood is not really providing any or as much structural stability.
As far as glueing down the foam to the OSB and to each other I used Liquid Nails “projects” having peeled off the thin transparent film they apply to the foam first.

[CodyO]

I elevated 1/2" plywood 2" above a 3/4" plywood frame for the track, all the area around the track was either elevated ply(City scene) or 2" foam around the elevated 1/2" so I can create depressions or elevations by stacking more foam.

[CRL]

I lay track directly on minimum 1-1/2” white beadboard styrofoam over a 1” layer of blue styrofoam over a wood frame. Cork is optional.

[CBQ Fan]

I use homosote board with cork on top of it. I find this to be much quieter than plywood.

[mark.hinds]

Since the mid-1980s, I've had cork on 1/2" plywood, as in the following image.  This has survived for 35 years and 2 moves, and noise is acceptable.  Never tried foam under the cork, but I can't see the need for it.  Do a test section.

[LIRR]

On my previous N scale layout i used 1/2” birch plywood for road bed on 3/4” plywood sub road bed. On my current HO layout i use cork on 1/2” homasote  on 3/4” plywood sub road bed

[CRL]

On my previous N scale layout i used 1/2” birch plywood for road bed on 3/4” plywood sub road bed. On my current HO layout i use cork on 1/2” homasote  on 3/4” plywood sub road bed

Earthquake prone area?

[LIRR]

No....i built modules of 3/4 ply. I was able to use 2’x4’ panels I could fit in the car. I cut three 3”x4’ strips for the box-frame and used the large piece for the top. This gave me 2x4x15”wide semi-permanent modules that could be disassembled removed and moved if need be. I went with the tradition 1/2 homasote, but I found the thickness varied and track wasn’t flat - a problem in N, probably would have been fine for HO. So I went to 1/2 birch ply, cut with jigsaw. Much more stable and consistent.

When I switched to HO, I stripped it all down to the 3/4 module to start over, back to homasote on the 3/4 ply.

[pdx1955]

Every layout  that  I have had used 3/8" plywood with cork and never had an issue  with larger yard areas or cookie-cutter  open grid scenery sections. Some  industrial  areas I've  had the track directly  on the plywood  and since those  are short and slow running  places, noise is not an issue. I have sections on my current layout  dating back 20 years and no issues  with them.