Recommended foam board?

What do you plan to use the foam board for? Extruded Polystyrene foam board is not good for structural support, nor is it good for sound insulation (it's actually noisier than plywood! It is used in the building trade for thermal insulation, and is very good on a model train layout as scenery forms. It can be carved & painted to look like rock formations, and can be shaped, painted, and covered with blends of ground foam and static flocking to make lush vegetation areas and meadows, plus it is very lightweight.

Homasote and Quietbrace are better used for sound insulation, but they are very heavy, which limits their usefulness for modules or portable layouts. I've never used QuietBrace because it is hard to find in my area. The last time I bought Homasote, it was also hard to find, with only one lumber yard carrying it in the entire county. Perhaps part of the problem is the lack of frame construction in the area, everything seems to be concrete block construction here, probably due to the impact of Hurricanes on South Florida's building codes.

Bill in FtL

Bill,

I plan to use it in place of QuietBrace on top of 3/8" plywood for the surface of the layout.  The stuff I saw doesn't compress like regular styrofoam and looks like it might even hold a screw, which I use to hold down the track.  My plan is Ross/GG track on cork roadbed on 1/2" foam on 3/8" plywood. 

I'd use Quietbrace but HD stopped carrying it in my area and only carries now an asphault impregnated sheathing - too much asphalt to bring in the house, and not a sound barrier.  I've only found Homasote at 1 lumber yard around here, and its in the mid 30's per sheet, and often has to be ordered.  Wish I could find the Quietbrace somewhere - I've used it before and like it, once painted.

Tom from Raleigh area.

 Green foam here. I didn't have much choice. Far better than plywood alone, but not what I expected sound wise.

An acceptable improvement, but it's still loud IMO.  (No roadbed, grass mat)

At 180lbs, it will dent slightly under a "sharp" knee, elbow, palm heel or knuckles.

Using a brace board is needed for "climbing".

Carving in it is fun, & easy.

I've been using cheap H²O based craft type acrylics for paint.

White glue, super glue, some silicone, etc , And though only fast and sparingly, or it will melt, hot glue even works as expected.

Heat is a factor. I've had PW track get hot enough to blister you at a bad track joint.

I think the radiant heat could do damage on green foam. A "sink hole" if you will...  

You might pick up a sheet to try out sound wise for a bit.

If you change it out. The worst that could happen is you'll have enough foam to stack & carve your own canyon from it .

Adriatic,

I assume the "green foam" you used is the Lowes stuff?  I noticed one side with lettering was smooth and shiny, and the other side was rougher with no lettering and didn't appear coated.  Which side did you leave up and paint?  How did you fasten it down?  Did you try to make a screw hold in it?

Thanks, Tom

I used Pink, Blue and Green foam panels.  It's all about the same unless you get into the structural high density stuff.  The Pink came in 2'X4' panels from Home Depot and the Blue and Green was available in 4' X 8' panels from Lowes.  The Lowes stores in my area are in two different Counties, that may explain the difference.  My layout base was constructed L girder fashion and topped with 3/4" plywood.  The 3/4" plywood was about half the cost of 1/2" OSB.  I found a Builders Surplus Supply that sells left over stock and deep discounts.  I covered everything with 1" foam.  My layout crosses over itself and I raised the upper track on 6" Styrofoam blocks and used Woodland Scenic Risers on one end and custom cut stryofoam panels to drop back down.  I covered everything with a skim coat of Strucolite and painted it.  I use FasTrack and have no issues with noise.  My friends that use tinplate track have noise issues.

To cut the chase a bit, the quietest layout I've seen as an adult has astro-turf with super snap track on it. (12x15? Three loop ovals.) 

 Mine is all wood scrap- 4.5" x 9', 2x4 frame, various runners with emphasis on the corners, and center. Done without much planning, as fast as I could, and to the best of my injured ability. 0-27,O,& Super O.

  A single sheet of homemade 7/16 plywood with flexible laminate glue, and DAP contact cement mix my stepfather whipped up, and "country boy" pressed in the garage, with various items, including the Lincoln.

I  ran it bare, then with the foam on it, then glued.

 Glue made it louder in the mid-range. No glue the center track, seemed to produce more lows. Overall less "booming" was better for me. 

 I'm pretty content with the outcome, but know now.... 

If I still could, I'd experiment with sandwiched felt, cork, thin carpet or carpet pad, or similar. And/or for roadbed support.

I used a tube of foam safe adhesive (Locktite if I remember right).

   Foam safe was suggested to me on another forum (rather expensive compared to the "other tube products").

Others claim Liquid Nail, or even caulk would have been "good enough".

 I think it was Lowe's foam, but there is a HD right there too, so???

I don't think it matters much either, but in theory, softer foam should be quieter.

I choose what I thought would handle abuse better, I had to be able to climb & lean on it. The grass matt rebounds, so you don't see any dents 

   The foam I bought had a clear protective skin on one side.(vapor? Hey... I think it was embossed Lowe's)

 I didn't notice until after it was glued down, and it peeled off some scrap being tossed.

   Almost three years, and the big sheets aren't shifted, or lifted. Nor do I think it will be an issue. I would peel it .

 On one piece, the barrier was "up". But the larger pieces went embossed side down.

 The "one", would have likely become an issue had I been laying ground cover directly vs a grass mat.

  After finishing a flat layout. I eventually played with the scrap a few months ago, and had a ball.

  It really is just so hard to mess up when carving foam. I can't push for trying it out hard enough.

  If I hadn't taught the dogs not to dig, and scratch, they could have carved it for me.

 The next layout will ideally also have thicker foam & terrain reliefs carved down into it by hot wire. 

  With the barrier removed, there is no "right side". It all takes paint the same.

 There is no "soak" to speak of, so a little paint can go a long way, if you spread it around fast enough.

 I didn't bother with screws to the foam/frame, except as posts to hold it still from side movement while it's glue cured.

  It's not dense enough for threads to grab well, the head/washer would have to be huge.

  Also, pressing with a large flat surface will help with it being "Water Level".

Pressing with separate objects allows flex over the glue, and it will have high and low spots. Though barely visible, future measuring from the ground may be affected.

 I didn't have the speed (dry time) or physical reach then, to use an adhesive spreader which would have helped level it too.   

Attaching things....

Most items do have screws, but not all reach to the wood. Some are just pushed into the foam like a thumb tack, to stop the item from shifting..

Some things just have nails, or even cotter pins as "stakes" 

  I've thought about going to nylon screws too, since the holes are there in the wood now.

A lot of sound travels through the metal screws.

  Some foam scenery sits in place on screw heads, sticking up about 1/2" above the wood & foam, to act as location dowels for holes on the foam scenery's underside.

Homasote is quieter. Maybe as quiet as the astroturf, (but I doubt it).

 My age at the time, and the fact it was long ago, make me question my own opinion, but my Grandfather used it, or a similar knock off.

  It dried out after a number of years, and released a dust out of the holes in the edges, that my Grandmother vetoed against, soon after it began."I like the noise better" she said..

 His old basement layout had its Homasote layer stripped off before it saw track.

  It was twice as expensive when I found it too. 

  That's why I didn't choose the sound board either. For the price, it didn't seem as stable, and with the constant vibration I feared dust. Nasty, fiberglass-like dust. I hate insulation type fibers in me.

 I intend to play with felt, rubber, and rubbery roadbed things on it when I get down to the basement. Foam? Oh yes there will still be some foam

By next summer I hope to start something on top of the bench work again. 

The strength and sound depend on the density and thickness of the foam sheets.

Extruded Polystyrene that is High-Density and 3" thick is the best choice.

Put that Owens Corning Fomular foam sheet on an open grid of furring strips.

Andrew

I used pink extruded polystyrene, paint and glue work well on it. I used 3m super 77 spray adhesive(foam safe) to glue to plywood and foam to foam. Make yourself a hot wire and you will just keep making forms and objects.  Extruded polystyrene is cut panted and used for outdoor lettering all the time. Coat the foam with latex paint or pva glue befor using any solvent or oil based paints.