I’m assembling my benchwork and was planning on using 2" foam for the top. Is a layer of plywood necessary beneath the foam if I have joists everywhere 16"? What has been people’s experience. I don’t plan on ever standing on the layout so I just need support for track, buildings, etc.
Brad
If you’re using 2" foam and will have at least a 1x2 (laid with the 2" horizontally), then no, you don’t “need” plywood. One of the largest home layouts in the USA, Bill Darnaby’s Maumee Route, is built with 2" foam and 1x3 L brackets, and he’s experienced no problems in the ten years that his layout’s been up.
A thin layer of 1/4" ply is nice to have under the foam, however, for hanging lights, switch machines and routing wires. It also helps deaden the sound a bit (which is only a problem if you run 100 MPH plus).
If you use 1X2 or 1X3 joists every 16 inches you shouldn’t need plywood under the foam. I have a 12 foot length with that arrangement and I’ve leaned on it several times. It didn’t have any trouble supporting most of my weight. And I’m not light!
I have a 4’ x 4’ RR built for Christmas. I used 1" foam and 1 x 4’s spaced at 16" c. I have not had any problems with it. You should be fine with the 2 " stuff and 16" c.
Scott
I’m using 1/2 plwood under 2" foam, but only cecause I’m worried my kids will climb on it. See I’m building the benchwork knowing I won’t be able to start the layout for perhaps another year. Long story.
Short–use the foam only. It iwll be okay.
I insert small pieces of 1/8 ply (1"x1") in the foam where I need to fasten or screw something. With that there is no need for ply and it is sure easier to do things with the foam.
I agree with all of the above. With 2" foam over 16" on-center supports, plywood is unnecessary. I laminated two 2" foam sections together for my N scale layout. I can pick the whole thing up without any flexing of the foam. Even with scenery, the layout is light enough to lift with one hand!
With your supports separated by 16", anything you need to hang underneath the layout can be hung on the supports. If necessary, you can always screw a piece of plywood or dimensional lumber between any 2 support pieces.
The money you save by not using plywood can be invested in more engines and rolling stock! [:D][:D][:D][:D][:D]
Darrell, quiet…for now
I’ve got 2-inch foam over 16-inch rafters, too. It works great. I would argue that plywood actually makes things harder, because you need to use a drill to put in wiring through the plywood. With foam, I just use an ice pick or one of those bamboo skewers to punch a hole all the way through.
I use 2" foam across joists at 16"o/c with no problem. I only is for the scenery though. I use 1/2" ply with 1/2" homasote under the track because as mentioned in an earlier post, it makes switch machine installation easier.
a friend and I made a portable layout with 2" styro, I was not happy with the cork glued down on it, seemed to be less secure.