Another Plywood Question Thread

HI...as you mention, there are many varieties of sheet products including various plywoods out there to use.  I used 1/2" 4 x 8 Underlayment grade Fir plywood.  It is typically 5 ply and not universally available at big box stores or more price conscious retail building material dealers.  Over the past several years, the item has become more of a specialty product and availability has tightened.  The reason I use Fir (from the west coast) is that it is simply more stable than souther yellow pine, especially in lower level basement areas with high humidity during parts of the year.  The underlayment grade gives you a "plugged and touch sanded face" with no voids.  I find it better to work with than what was formally referred to as "CDX," a cheaper product typically used on roofs or sidewalls in new construction.  The CDX product is not sanded and will have voids on the face of the product.

You certainly can use CDX and save some money over the underlayment product, but the savings wouldn't be huge.  Both products should be fine 16" on center or even 24" on center.  Of course, weight load can become a factor in some situations

Bottom line....numerous products work just fine. in my case, it's simply personal preference...good luck!

Thanks for the input! I don't think I saw CDX at the store, but looking at common applications it includes sheathing, which make me lean towards some of the sheathing plywoods I saw. While cost is a consideration, I don't want to just rush for the cheapest stuff (you get what you pay for), however the sheathing is at a good price for me so I may go that route.

I forgot to mention that I'll add framing underneath the plywood using 2x3's or 2x4's, on 16" centers. 16" may be overkill (not sure) but I am going to be assembling in 4' wide sections. 16" centers makes for clean, easy division breaks down to about four 2x4's per sheet of plywood (3 lengthwise plus 2 halfs for end piece).

Just make sure you use plywood, NOT OSB, NOT CHIP BOARD, NOT PRESSED SAWDUST, just plywood 1/2" and you should be fine. If your train room is in a damp area. Consider outdoor plywood.

@prrhorseshoecurve posted:

Just make sure you use plywood, NOT OSB, NOT CHIP BOARD, NOT PRESSED SAWDUST, just plywood 1/2" and you should be fine. If your train room is in a damp area. Consider outdoor plywood.

The biggest problems I've found with these 3 plywood alternatives are:

Weight (much heavier than plywood).

VERY hard to screw into.

O Gauge CJ: 2 x 3's, 16" on center will give plenty support. Use these instead of 2 x 4's and use the savings to buy plywood instead of these 3 alternatives

On my larger area I used interlocking 1X4's with 3/8" plywood on top.  It does not take long to layout and cut all the gaps.  The picture is representative, not my frame work.  The boxes that the framing makes are all about 18" square and the 3/8 has zero give over that.

@prrhorseshoecurve posted:

Just make sure you use plywood, NOT OSB, NOT CHIP BOARD, NOT PRESSED SAWDUST, just plywood 1/2" and you should be fine. If your train room is in a damp area. Consider outdoor plywood.

I have a dehumidifier but I am not always able to get to it as soon as it gets full, so I'll keep this in mind, thanks. Wasn't sure if there were any concerns with handling treated plywood with hands or inhaling any dust after cutting (for example, treated wood is not recommended for raised vegetable garden beds due to risk of chemical abosrption).

@0-Gauge CJ posted:

I have a dehumidifier but I am not always able to get to it as soon as it gets full, ..............................

I had that problem in my basement so I ended up getting an inexpensive submersible pump and sticking it in a trash can.  I raised the dehumidifier up on a platform (sawhorses and a piece of sheet stock).

I put a drain hose on the back of the dehumidifier and sent it into the pail, then I ran a discharge hose from the pump out the basement window.

I now have an automatic dehumidifier setup.  Works great.

John

Not sure where you live but....  One thing to consider is to go to a REAL lumber yard and discuss it with them.  When working on a project at one point I was amazed what they had available for Plywood vs the big box stores.  Of course in addition to being a lumber yard, that actually had a millwork/cabinet shop on site.  Don't underestimate the "old school way" to get things done, "correctly".

As you mentioned, you might pay a few bucks more, you can then decide if it is worth it.

Since you asked for opinions, I have one, LOL.  I started my layout in 2014, I was still working and wanted to save some time.  I used Mianne benchwork which I think is a great product.  It is not cheap, but it is good quality, goes together very easily and is very sturdy.

For bench top I used a product called Blondewood from Lowes.  It is a 7 layer 1/2" plywood with a very nice finish.  But my primary reason for being it is a belief that the 7 layer build up would resist sagging.  So far it is staying nice and flat.

Attached are a couple photos, from early on.

Aflyer

@SIRT posted:

Utility Panel (Common: 1/8 in. x 4 ft. x 8 ft.; Actual: 0.106 in. x 48 in. x 96 in.) Home Depot Model# 833096

$18.98

Lauan door skins placed over 1x2 T ladder frames is all you need. Pick sections up and carry them anywhere. Can be stored in a closet upright too if needed.

Steve,

Can you elaborate on the T ladder frame construction?  Also since it's only 1/8 I assume you are gluing track to the board/roadbed?

Thanks, Don

@dmestan posted:

Steve,

Can you elaborate on the T ladder frame construction?  Also since it's only 1/8 I assume you are gluing track to the board/roadbed?

Thanks, Don

My layout didn’t require roadbed using that high profile Gargrave’s track, so I tacked down FELT prior to laying the track. I also added carpet padding underneath the modules with liquid nails. Edge roadbed is just sculpted Styrofoam strips. Short screws were applied to sides of track to keep it in place prior to glue application.

Please see my Construction album from years ago for ideas…https://steves3roscale.shutterfly.com/pictures/3168

Go to Shutterfly, I have 112 Albums containing 21,000 model photos here -

https://steves3roscale.shutterfly.com/pictures

Other factors to consider include what you plan to do on top of the plywood.  Will track be laid directly on it, will it be visible, or will paint or scenery be applied directly to it?  If so, go with a good quality B/C or better plywood that has a smooth surface.  Will you be covering it with homasote or foam?  If so, appearance and paintability don't matter, so just go with something sufficiently strong (OSB or CDX) - these products are used for construction - they're relatively inexpensive and plenty strong for a layout.  The best way to get a flat surface is to use straight 1x4 lumber and let it acclimate in the layout room for a few weeks before using it - return any boards that warp or twist.

I use L-girder benchwork, pioneered by Linn Westcott, which has been a standard in model railroading for 50+ years - easy to build, inexpensive, lightweight, strong, and easily modified.  Plenty of info about it in books, magazines, and here on the forum.  I use 1x4 supports and 3/8 or 1/2" ply with 2x2 legs - never an issue, but I don't climb on it.

Remember that you're not building a house - good enough is good enough.  Benchwork is a one-time task and expense - build an adequate foundation once and you're done, but don't waste time and money overbuilding it.   

I'm a little late, but thank you all again for the replies.

@Mallard4468 posted:

Remember that you're not building a house - good enough is good enough.  Benchwork is a one-time task and expense - build an adequate foundation once and you're done, but don't waste time and money overbuilding it.   

This is the general sense I am getting, which puts me at ease thanks again.

My advice was going to be the same as Mallard's.  If it is going to be covered you can use almost anything that is structurally sufficient. 

Like Millard4468 I build my layout with the Westcott L-girder design benchwork. My longest section is 20 feet with only four legs. On top of the subframe I have 1 x 4's 12" on center with 1/2" OSB. I did however substitute pine 2 x 2's with a 2 x 10 laminate beam that I ripped on my table saw to 2 x 2's. This will never warp or crack, is super strong and takes screws without splitting.