would personally not use homasote, its messy and dirty, the pink foam builder sheets are a better alternative, and you can layer them and contour them to your layout.  as far as the wood, I don't have a preference, but Plywood is the better route in my mind, I used 3/4" plywood on  mine, I can walk on it to get where I want to be

I also put my layout on wheels to move it around and off walls.

To each their own but I disagree on homasote.

#1 I find it superior at sound dampening.

#2 It's not crushable like foam.

#3 If you cut using a sharp knife, there is no mess or dust.

The reason I say this, our local club used 1 inch thick foam. It is a nightmare to work with later. If you have to lean on the layout or set anything down you get dents. Nothing actually sticks to foam long term, so anything glued or painted- scenery is always coming up and rips up the paint and glue. It's not any quieter for using thicker foam, and a lot more pain long term. I've got 80x9 feet I have to deal with and want to throw something whenever it involves mounting something or changes, even repairs.

At home I used homasote with felt on top nd by far, this is the quietest table top I know of.

Again, sorry to disagree, but if I had my way, never, ever, foam again, and definitely not thick foam like 1 inch.

I agree with Vernon. I have built two layouts with homasote, it is good stuff and can be cut and trimmed with minimal dust.

Re OSB, foggetaboutit and go for good plywood. Depending on the benchwork, 1/2 inch plywood with as many plies as you can find is usually sufficient. Spend the money to get good plywood.

Also, need to mention the burn marks in our foam from stray soldering  irons, wires burning up, anything that ever gets hot (even accidentally). Recently someone wired up a buble tube water tower to track lockon. look us a week or two, we kept smelling burning but intermittently. It was on a siding that was not powered all the time and when running command got full 18V melting the water tower base and light bulb into the foam.

Or there was that almost fire story of Atlas switch motors melting into foam in that one post. https://ogrforum.ogaugerr.com/topic/12129987998543558

Sorry, I know people use it and like it (foam) and it's light, easily accessible, relatively cheap. I understand why people like it, I just want to point out the known problems there can be on the other side of the story.

I'm not trying to cause panic paint foam as some huge risk. Just I have had my own bad experiences and completely opposite good experience with the alternative like Homasote. I also do understand the dust if you use a saw. Just don't use a saw, and cut with a really sharp knife by scoring it a few times and way less mess. Again, if mess is your concern, I understand, but here are ways. Again, I have some experience with both and never again foam as a base. Mountain or scenery OK, but not for my main table plan.

Homasote or Faced Sound Board over 1/2" or 15/32" plywood.  Most like Baltic or Birch... CDX (Plugged/Sanded) on one side is absolutely fine as well.

@Vernon Barry posted:

Also, need to mention the burn marks in our foam from stray soldering  irons, wires burning up, anything that ever gets hot (even accidentally). Recently someone wired up a buble tube water tower to track lockon. look us a week or two, we kept smelling burning but intermittently. It was on a siding that was not powered all the time and when running command got full 18V melting the water tower base and light bulb into the foam.

Or there was that almost fire story of Atlas switch motors melting into foam in that one post.

Soldering irons, wiring problems ,defective switch motors, overvoltage to an accessory.... It sounds like the foam is the least of your issues.

I've had good experience with homasote over plywood as well.

@RickO posted:

Soldering irons, wiring problems ,defective switch motors, overvoltage to an accessory.... It sounds like the foam is the least of your issues.

A couple of "harmless" flakes working together can cause an avalanche of destruction.

I would not use the Atlas rail joiner feeders as a main, primary or only supply.  Rail joiners may not provide a reliable electrical connection.

Nothing beats a properly soldered connection direct on to the rail.

The light wire on the Atlas joiner is OK for a short feeder.  Your  main buss or star supply should be in the 12 to 16 gauge range depending on length required.

With regard to the plywood versus OSB  debate,  look at new home construction.  Almost every new house has OSB  for floors, With joists set at 16 inch centers.  If you can put a 300 pound refrigerator with another 200 pounds of food and ice or an 125 pound washing machine holding 150+ pounds of water with no deviation from level,  then overpriced plywood is not necessary.

I am close to 300 pds  and used 1/2 inch OSB on a 2x4 frame covered with Homasote and been great on two layouts the first was up for almost 20 years and I recycled that OSB to my current layout now.

I used 18 gauge stranded wire which is more flexible and malleable than solid wire, and it won’t split or sever. It is often used for indoor applications such as electronic devices, circuit boards, and speaker wires.  My layout is 15 X 6 Ft.  You may want to use 16 gauge is you layout is larger.

@RickO posted:

The lighter weight of osb makes it easier to work with.

Actually OSB is heavier than plywood, but not by much.

John

@third rail posted:

With regard to the plywood versus OSB  debate,  look at new home construction.  Almost every new house has OSB  for floors, With joists set at 16 inch centers.  If you can put a 300 pound refrigerator with another 200 pounds of food and ice or an 125 pound washing machine holding 150+ pounds of water with no deviation from level,  then overpriced plywood is not necessary.

Builders use OSB because it's cheap.  Period.

You couldn't pay me to use OSB on a train layout.

I didn't even consider OSB when I built, and I wouldn't now, even though it's cheap.

there is a reason why OSB is cheaper than real plywood....and it's not b/c it's better.   

Whenever this topic comes up, it generates strong opinions, so here's mine.

If you're putting another layer of something (foam or homasote) on top of it, OSB decking is fully sufficient - as others have noted, it will support roofers (and snow loads), so it will easily handle toy trains.  3/4" plywood is usually overkill and a needless expense.  If one isn't using foam or homasote, then go with 1/2" plywood.

I've used both homasote and foam.  Homasote really sucks up the paint, deadens sound more than foam, and will hold the track in place with nails or screws; foam is light and easy to work with, but the track needs to be glued down.  IMO, comes down to personal preference.  Next time around, I'm thinking of going with 1/2" plywood and cork roadbed - no homasote, and I'll use foam for land forms.

some people don't like OSB b/c of all of the cr*p that's it made from.  others don't like to have to inhale said cr*p when you cut, sand, plane OSB.

FWIW, most of the layout builders who have a furniture making background....myself included....use baltic birch.

i use regular plywood for lots of jobs.  i never use OSB for anything unless i have no other option.  i straight up hate it.

it's still a Free Country and not everyone has to agree. 

I don't even have a furniture making background and I used baltic birch.   It was really nice wood to work with, and truly rigid, no warping with that stuff!

@Mallard4468 posted:

foam is light and easy to work with, but the track needs to be glued down.

You can use these (for thicker foam).

You screw the metal part into the foam, remove, add a drop of gorilla glue, and screw back in.  When dry it holds a #6 screw really well.  Flat head works better with Fastrack sections.

I learned it from Ken Hoganson's book  21 Great Track Plans For Compact O Gauge Layouts.

John

I also hate OSB, but with homasote, I think that you could go with either.  Homasote holds neils/ screws just fine.  Both plywood and OSB are loaded with glues and resins.  Not sure if anyone has rigorously studied which has more toxic chemicals.   I also think you can get by with 1/4” plywood or OSB if you have a very sturdy subframe.  Many people use 1x4 subframes, but with 2x4 subframe you can use thinner plywood or OSB, IMHO, at least that’s what I do.  

Most of the products we use, even natural ones, contain things that can damage the lungs - anytime you cut, sand, or finish anything, an effective dust mask or respirator should be worn.  Eye protection too. 

I have an extensive background in woodworking and furnituremaking.  I love using good materials, including baltic birch.  But I also feel a responsibility to be a good steward of resources, so I hate wasting stuff for no good reason; as such, I wouldn't hesitate to use OSB where appropriate - it's made with things that would otherwise be burned or go to a landfill.

Baltic birch is beautiful stuff.  Premium AC grade plywood with at least 7 plys is also excellent for decking a layout and was my choice.  It's flat, smooth and has never warped for me.

@swrr posted:

Many people use 1x4 subframes, but with 2x4 subframe you can use thinner plywood or OSB, IMHO, at least that’s what I do.  

I'm not sure why the 2x4 subframe would be better than the 1x4 subframe, it's really all about how the benchwork is designed and built.  You can make very solid 1x4 benchwork and also very rickety 2x4 benchwork.  It's all about the workmanship.

Wow Third Rail.  Don't know what to say.

Yes, almost every new house being built uses OSB as flooring, because it is absolutely the cheapest, most inferior product that a contractor can buy that will meet the minimum building code requirements.  Go into one of those big new houses and thump your foot on the floor.  The dishes and will rattle and it will sound like you are beating a drum.

Having spent years repairing cheap OSB failed flooring and roofing, I can guarantee you that the extreme weight you describe will cause the OSB to sag.   And, you'd better hope that there is not the slightest leak from your appliance or weather that works its way to the OSB,  because that OSB will turn to wet carboard and disintegrate in short order.  (Of course, since it absorbs the water like a sponge, it will turn totally black with mold first!)

Yes, I know you won't be jumping up and down on your layout, but don't kid yourself about the lousy quality of OSB.

Plywood is much stronger than OSB, and exterior grade plywood is the best thing there is.  That is why it costs four times more.   ( I am stunned that folks will drop $400 or $500 or more on an engine at the drop of a hat, but won't spring for two sheets of quality plywood when building their tables.)

Gunnrunner makes a good point about the careful use of 1x4 being very strong.  But, the actual building activity is much easier and quicker with 2x4s, because its edge is twice as wide and you don't have to worry about splitting the wood with nails or drive screws.

And, as I've mentioned elsewhere, even 2 x 3 studs are extremely strong as cross members up to about 5 feet wide if you use a high quality construction adhesive to glue down your layout top.  Table legs are really strong if you screw two of them together, not on top of each other but with the narrow edge of one stud down on the wide edge of another stud, forming an "L" shape when viewed from the cross section.   It is easy to add casters to the bottoms of these legs and the table can be moved about with ease.   And, kiln dried 2x3 studs are only a little bit heavier in weight, and a little more expensive, than 1x4s.

Hope this info helps.  If you want to use OSB and 1x4s, then by all means go ahead.  Whatever makes you happy!

Mannyrock

When we built the AGHR layout, we opted NOT to use Homasote or foam as a base layer on top. Yes, it was a bit noisy, but as ground cover was added, it quieted down. What also helps is the use of solid rail track (Atlas) versus Gargraves (but used Ross turnouts). With Homasote or foam, you'll have some mess issues with cutting/shaping and hypothetically heat damage from solder, but it comes with the territory. When I've built small layouts/modules, I've opted not to use foam or Homasote. Besides, it's easier on the budget and in some parts of the country (California) you don't have the issues trying to find the stuff.

I used half-inch homasote on half-inch plywood sheets and 2 x 4s for the supports. You could dance on my layout which has been up and running for over 10 years now with no problems.

3/4 plywood is too thick and homasote is good. And there you have it. 👍 😉

Vern when we started, my brother-in-law and his sister insisted on 3/4”, 2 X 4, etc. it came out fine and can support a marching band. When we started on level 2, I didn’t ask and used 1/2”. Plenty strong.

agree with Mannyrock, but then I always tend to overbuild my fences too, in anticipation that I want them to hold in a bull as well as the cows.

Something to consider is a combination of plywood and foam.

For instance, my layout is 95% plywood and 5% foam.

The plywood is good quality, has not warped and has stood the test of time. I used one-half inch thick plywood which has worked for me because I never climb onto my layout burdening it with all my weight, but only reach over it to deal with a derailment, etc., encumbering it with only only part of my weight.

The one inch thick foam is the light weight base for a removable river, a recent addition, with boats and barges on it.

I will post photos shortly. Arnold

See photos below showing plywood tables with trains on them, and removable river with foam base and boats and barges on it:

Arnold

Over the years for clients I have only used 11 ply Northern Birch shop grade 23/32" plywood.  Not stain grade but  otherwise excellent building material.

However, on my own RR I have used a variety of  decking materials just to settle in my own mind some of the biases I have held.

The RR is rather large with 225 linear feet of modules so there is a fair amount of space for different material usage.

For plywoods I have used 5.5,  6.0 mm ,  3/8" 1/2" 5/8" 3/4" A/B or B/C rated.  1/2" & 3/4" press boards.   Also used is !/2" sign board, 1/2" OSB and  3/4" Advantech.

My two favorite skins are the 5' X 5' format Baltic Multi ply and the 23/32" Advantech.

For support frame work my go to material is 3/4" plywood ripped to 8' X 3 1/2" for cross members on 16" centers.

Advantech is rapidly taking over new construction for flooring.  Check out Huber industries for details.

Bottom line:  IMO, Proper support frame work can make almost any decking selection work fine.   However many folks do  not  follow adequate framing principles.

@Kenneth Willis Kenneth, I just want to say that it is so cool that you are building a 2 rail layout! Nothing against 3 rail but I hardly ever hear about folks starting a new 2 rail layout these days.

As for your question I prefer the Advantech board that Tom mentioned with homosote. I used the foam once a long time ago when I was in a club and I hated it because the mess was so hard to clean up. We cut the foam with a sawz-all (or however you spell it) and the small pieces got statically charged and they kept sticking to me. True homosote will make a mess too when you cut it with a saw but it vacuums up quickly. Just my opinion. Best of luck to you in whatever way you choose to go and please keep us posted on the progress of your layout.

@Tom Tee posted:

My two favorite skins are the 5' X 5' format Baltic Multi ply

Absolutely agree!!!

@Berkshire President posted:

Builders use OSB because it's cheap.  Period.

You couldn't pay me to use OSB on a train layout.

That is a misconception about the material.  OSB has greater strength to resist staple and nail pullout because of the non-linear orientation of the strand matrix.  The strands are all adhered into a single matrix creating a uniform structural system whereas plywood is simply thin plies of wood glued to each other.  Plywood delaminates more readily as a result.

When I started in the construction industry over 30 years ago, I used to hold this same myth as truth.  My favorite structural engineer who is older than my father mentored me a great deal over the years and was the one that gave me the facts about OSB over plywood in structural situations.

There is no debate that plywood is much more attractive and practical as a finish surface material, however if the OP has plans to face the OSB with another material, for purposes of a layout there really isn't much difference outside of cost.

@Tom Tee posted:

Advantech is rapidly taking over new construction for flooring.  Check out Huber industries for details.

Depends upon where you live.  The last time you suggested it I started researching availability here in the Northeast and couldn't find it in stock.  I just checked now.  Same thing.  So in the Northeast anyway it cannot possibly be taking over new flooring construction.  It would have to be other brands of OSB.

John

@Tom Tee posted:

Bottom line:  IMO, Proper support frame work can make almost any decking selection work fine.   However many folks do  not  follow adequate framing principles.

I totally agree with Tom's above statement. In the mid 1990s, I bought an excellent booklet on building benchwork that provided step by step instructions to have proper framing as mentioned by Tom. I still have the booklet,  but it's buried in my basement and I can't remember the title and author of it. I bet someone on the Forum knows this information.

Anyway, I followed the instructions to the letter. As a result, my 25 year old benchwork has never warped or sagged and is as solid as a rock.

Arnoldo

One more thing: don't take shortcuts when building the framing of your benchwork. I did that with my prior layouts, which turned out to be a big mistake. Arnoldo

Hi John,

I entered your zip code in the Huber Industries web site for retail locations and that produced eight retailers within 25 miles of your zip code.  Granted, information can change but if you want it, it is available.

Around here you will see skids of it being delivered to construction sites.  Advantech has months long exterior to raw weather exposure rating with out any reaction to moisture.  The builder does not have to be concerned about rain or snow in getting the roof and windows installed.

I even installed it on 32" centers on my RR.  Advantech is absolutely flat, no noticeable deflection on 32" centers.

I have used it as an extra top layer when ever I did floor covering in a laundry room.  Out of balance washers can really dance around.  Not with Advantech.

Also used it in an existing second floor condo weight lifting exercise room.

No, you do not have to use it but if you want the best at least consider it.