Foam board on top of OSB for layout worth it?

[AFGP9]

I have built 4 layouts and 3 were open grid. The one I have now is 10 years old. I used 1/2" plywoood nailed to a frame then on top of that I glued 2" blue foam board. The 2" stuff allows for below grade landscaping and is easy to "plant" trees into. To secure my track, I ballested the whole thing and poured diluted white Elmer's glue over that. No nails or screws. The track has never moved. I have used this method on all my previous layouts. I could have used OSB since I had a supply of both OSB and the plywood. Looking back, I wish I had used the OSB and saved the plywood. My opinion, use the OSB and 2" foam board. 

[Buckeye Riveter]

Phish...You know what I had, all foam and no ply/osb. The deck screws grabbed that 2" blue foam for almost 18 years and the track never moved. It was a pain to remove the track from the foam, when I tore it apart. It was secure.  In fact, on the second phase of the layout, I didn't use as many screws through the track and no problems.

[lion88roar]

Nish
You don't want the screws going through the foam to the ply/osb... that would transfer the vibrations from the track to the ply/osb. You just want screws long enough to go through the track into the foam to keep the track from shifting. When I built my last layout I used 2x4 ceiling tiles that I  glued to 1/4 inch plywood. The ceiling tiles provided the additional grip to secure the track screws, however they did not provide the hoped for sound deadening. My next layout I plan to use the 2 inch foam sheets, that way I can create creeks, ponds, and lakes much easier (as you said), and it will allow me to make recessed areas for the track. I plan to use strips of ceiling tiles on top of the foam that I will use construction adheasive to secure them to the top of the foam.

[Nish]

Well if you’re not doing open benchwork, it’s a lot easier to create depressions below the roadbed level in foam vs having to cut holes in the osb/ply table top, for example a creek bed or pond. It’s also a good sound deadener. I suppose the downsides would be securing the track requires long screws or nails if  you dont want to liquid nail All your track to the foam. I’m working on a club layout with a foam top right now and it’s not really been a problem. 

 

John

[Sturgeon-Phish]

I'm ready to start placing track and wiring on my new layout and I've not decided on to put foam board like Lowe's Green Guard XPS on top of the OSB or not.  The track will be on a high density foam roadbed.  What are the pro's and con's of the foam board on the top surface of the layout?

Thanks,

Jim