Strength of Homasote

The answer is NO.  Homasote does not have any structural strength.  I have seen an N scale layout with only Homasote as the roadbed with supports every 16 inches and it sagged.  Homasote needs a structural base such as plywood.  Stick to your original plan of using plywood as a base for the Homasote.

Regards,

Ed

It has zero strength

I had a 4x8 layout as a kid using homasote as the platform top.  No plywood.  I forget the spacing of the framework, either 16 or 24 inches on center.  The homasote eventually sagged between all the framing.  So, I would say no to using just homasote as your top.

 

Rick 

This isn't what I wanted to hear.  But thank you for letting me know.  Back to the design board it is.

You might want to consider 1" thick Gatorfoam that I used for my helix and ceiling track as seen in my Photo Tour .

 

Securing track requires special treatment.  The light weight and easy handling and finishing makes up for the high cost securing track.

Nice idea, but I don't think that the Gatorfoam will fit in with my overall plan.  Except for over the window, I have to have wood for being able to fasten too for a fascia and crown molding.  Wife said it has to look nice.

Having 9 inches to work with is plenty, although a little tough to see that high up. I used 3/4" MDF and just recently installed the Woodland Scenics Foam Roadbed underneath it. It was so loud before, especially with the sound echoing off the hardwood floor. Now it is much better with that foam under the track.

 

I would also recommend using plywood and not MDF (as I did), because the plywood is so much softer than MDF, it will absorb the noise better from the start. Just use a good cabinet grade plywood, using your shelf supports on the studs, and it will come out great.

Sinclair,

I have 9 inches from the tops of my doors to the ceiling.  I used 3/4 inch shelves with cork on top.  My brackets are underneath the shelves where there is wall, and l brackets at the doors with the shelf on top.  Yes, it isn't as much clearance as I would like, only about 8 inches, but I work with what I have.

The whole shelf surface would be covered in Homasote and the Atlas track would be placed on cork on the Homasote.

 

Mark, I've seen photos you've posted before, and that has been some of my inspiration.  Glad to know that others have made that small headroom work.  I've got to figure out how to hide the braces as that was her request.  I have some ideas, I just need to take a long field trip to Home Depot to see what my options are.

Sinclair,

Yes I had to clear the shelves and brackets with my wife, although it was her idea for me to build this since we don't have room for a layout.  it is in a back portion of a finished basement room, and there are already lots of shelf brackets of an old style in the room.  I've seen pictures and videos of guys who made real attractive shelving for this purpose, but they have much better skills and tools than I have.  You may recall I have a fourth wall that is brick.  I bought some all-thread and anchors to hang the shelves from the ceiling.  I got 3 anchors in, before spring came.  You may want to see if your wife likes that idea.

Just use nice decorative shelf brackets and you don't have to worry about her seeing them. I got some from Lowes that matched the room decor and color, although mine is in the bar and gameroom.

Excellent suggestion.  I saw someone custom made his, (one of the guys I was referring to earlier).  However, I have seen what you suggest in the Lowes or Home Depot.

78" span......unbelievable someone would ask that. homosote is pressed paper/cardboard! those shelf layouts look like a hassle....whatever turns you on i guess-jim

Well, there are some of us that have never used Homasote, nor have the ability to have nice layouts.  For me it's either this shelf or nothing.  Surely given that choice you'd pick the shelf over nothing.

 

Besides, this forum is for us to come to to learn, not get ridiculed.

I'm with you, Sinclair!  Keep asking questions.  Sometimes common items in one part of the country are unknown in another part.  When we lived in Virginia, I went into a building supply store, and asked the sales person for homasote.  He looked puzzled, then asked if that was anything like creosote.  I couldn't fault him, they didn't carry it.

1/2" plywood with 5 or 7 plys will work great.

 

For sound reduction, Laidoffsick had the product. Closed cell foam or vinyl. Everyone doubts when I bring this up, but I use the 2mm, yes, 2mm closed cell foam made for use under laminate floor installations. I get a 21db sound reduction. FasTrack. Most of the sound emanates from hollow cars like boxcars or passenger cars. The Polar Express RTR LionChief set running fast is about 72db. There is an iPad app DB 10TH that you can use.

 

So, plywood for strength with shelf brackets and something in closed-cell under the track. Nice and light, strong enough and will limit the sound to tolerable.

 

Atlas track with one of the closed-cell or cork roadbed products may get you into the high 60's sound wise.

 

Edit: PS. Why not notch around the blind\window trim and make that section removable for maintenance? Then you could drop the height. You'll still have room for the track and train to clear.

The problem with the window is that the vertical blinds are mounted above the window which is high to begin with.  So the shelf will be sitting right on top of the blinds which stick out 3 inches from the wall.  And the window is so long that if the track is below the top of the blinds, the train will hit it going around the corner and I really don't want to bring the track farther from the wall then I already have planned.  In the image below (From SolidWorks.) you can see how the blinds stick out.  In the image of the track plan the window is along the top wall.

 

 

If you cut out 40" wide [(36" window + (2 * 2" trim)] by 4" deep (clearance for blind to move) on a 12" shelf you would only have to shorten the approaching straight by the 4" in that area.

 

What's your planned set-off of the center rail from wall? It should be 3.5" to 4" anyway.

 

I am just suggesting to mount the shelf flush to the wall on the ends with a cut-out around the window and trim. I can't see it changing the track spacing that much. It looks like you are at 4-5 center rail already.

 

Mock up a piece out of cardboard and check it out.

 

What do you need to clear the doors? 74"? Then you could set the shelf height at the highest door trim height and drop down to 74" in front of the window.

 

Oops! I forgot it's a double wide window with trim. The plywood shouldn't flex on that span.

Sounds like it would work.  I agree on the cardboard mockup.  In fact, I should have done that on mine.  I would have saved some grief.  It seemed like such a simple project at first glance.

 

For the Original query, YES, use Plywood, I'd go as far as putting a 1X2 fascia glued and screwed on it to add span strength.

 

Also, in place of homasote you can use Celotex Soundstop. It has no structural strength but eats sound well as that is what is is designed to do.

And no cork or other roadbed needed on it.

It also costs less than homosote, at least around here.

 

Now, as far as bumping out around the window, you could at least get down to the top of the window by notching around the curtains. Can't hurt and no-one will be looking at that anyway.

Sinclair,

 

I agree with Moonman. I would go with the seven ply if you can find it. Definitely more rigid. Best of luck.

 

Andy

7 ply it is, if I can find it.  And some crown molding on the bottom side and some trim molding along the edge to pretty it up for the wife.  Now how to hide the wires?

The 7 ply can be found with a sanded side, but not as pretty as something like cabinet grade. Used for boxes for expensive equipment and such. But, it's definitely strong for a 1/2" piece of wood. I would try a lumber supply rather then the home store. 5 ply will work if it becomes a chore to source the 7.

Being the home stores don't even know what Homasote is around here, let alone sell it, I've already got to go to a lumber supply so that was going to be my 1st look.

 

Go to this website.  It lists 20 towns in Arizona where Homasote might be found.

 

http://homasote.com/WhereToBuy/Default.aspx

 

This next part relates my experience with Homasote which seems to differ from the experience of the other responders.

 

As to the strength of Homasote, it depends on how you use and support it.  I've been building 8'x4' tables without any underlayment for more than 50 years.  The table consist of a 1"x3" frame with interior supports on 16" centers.  The Homasote is secured with woodscrews along the edges and interior.  No sag and I used to walk on the tops when I was very much smaller.  No noticeable sag.  The Homasote was painted on all surfaces.

 

However, if you using Homasote as a roadbed under the track then you will need to support it with plywood or splines.  Period.

 

Jan

Sinclair, like others have said, go with Celotex.  Here in Arizona it is a quarter of the price of Homosote and functions just the same.  However in my area (Prescott) lumber stores don't know it by its brand name.  They call it "white builder's board"  Same thing.

 

I've used it over plywood on layouts forever, never had a problem with it.  Just glue it down with the painted side up and you will have a great base for your track or whatever. I tack trim along the outside edge of the tables to hide the plywood/Celotex edges and you never know it is there.

I'll be using cork as the roadbed, so the Homasote would be to cover all of the plywood, and I will be putting an edge on it.  I'll have to look for the Celotex.  Thanks.