Depth of foam board on 4x8 layout

[kdgrant6]

I'm ready to attach my layout on a 4x8 sheet. It is now atop a 1" sheet of Owens Corning FOAMULAR. 

Should I slide another 1" sheet underneath before things are attached?  I know much depends upon what I plan to do with scenery, especially water.  Any other considerations?

THanks for any help

[jbrock27]

Not sure I follow Ken.  Are you asking about putting 1, maybe 2, 1" thick sheets of 4 x 8 foam board on top of a 4 x 8 sheet of plywood? 

[kdgrant6]

Sorry for the lack of clarity.  The layout now sits atop 1" of foam.  Underneath that foam is the plywood top of the train table.  I was wondering if it would be a good idea to slide another 1" sheet of foam between the table top and the foam that's already there.

[jward]

I am nogt sure what you would gain by disturbing what you have already built. it seems to me that you would be better off leaving things as they are. trying to lift that sheet may cause things to shift out of alignment. it' sort of like jacking up a house to build a basement underneath.

[kdgrant6]

That's a good comparison.  Thanks.

[Trainman203]

How deep you want your cuts for rivers and ditches dictates.

[Irbricksceo]

I used a 2 inch piece to allow for a lake bed and small dips in land but it all depends on what you want, as does most of the hobby.

[Pacific Northern]

It is your base level, or lowest level.

For any height above you simply add more foam where you need more height. For raising, or lowering, track levels to new heights the woodland scenics riser system is your best friend. Going up levels is easy, if you want to go down, then add more levels of foam.

[DAVE2744]

Trying to add a bottom piece of foam to your already occupied foam is going to be difficult at best.  As you would only be gaining a couple of inches anyway, you could do the following, as I have in the past.  Before you move the foam onto the 4 x 8, plan your waterway on the 4 x 8.  Cut out the plywood.  If the waterway crosses a support piece of wood, add wood "doublers" on the side of the cut into piece to add strength.  After you mount the layout onto the 4 x 8, you can cut out your foam to expose the new waterway. You can cut into a support piece about 50% and still have plenty of strength if the support piece is not too long or the cut not too wide.  Dave

[kdgrant6]

Thanks, Dave.  Good sound advice.

I've decided to leave the board with the 1" foam on top.  I have Woodland Scenics 3% inclines doing a loop.  I plan to build up the area inside the loop as a mountain (a monadnock, if you will) and do a lake halfway down its slope.  The stream that empties the lake will disappear between two hills.

[jbrock27]

Monadnock, as in New Hampshire?

[jward]

a monadnock is a geological term. it refers to a hill on a plain, that is not connected to other hills and rises well above the plain. if anybody is familiar with the Washington dc Frederick Maryland area, sugarloaf mountain would be a prime example.

and yes, that sounds a lot like the mountain in the centre of a 4x8.

[jbrock27]

Ahh, like Mt. Kineo.

[kdgrant6]

We have Glassy Mtn. in upstate SC, a bald front with trees on top.  It looks rather like a primeval anthropoid emerging from the earth.

[electrical whiz kid]

If you are going to have even hilly terrain-as most of us at least have-then I would strongly suggest taking your time through the planning stages; this way, it will tend to go smooth.  As far as strength, that 1-inch stryrofoam@ is pretty strong for this purpose intended; however, one might put frame of pine, poplar, etc under it for stability.
SGT. C