Plywood then Homasote or vice-versa?

The Homasote is on top. Not sure why you want the styrofoam.

Good Morning BobRoyals,  I use 1/2" homasote on top of 1/2" plywood.  That has always provide a good solid base on which to lay my track and adequately served to reduce track noise. If you are set on using all three materials I would suggest plywood on the bottom, then the extruded foam board and finally the homasote.  The homasote on top would give a relatively solid surface on which to attach your track.  The extruded foam board beneath it would further deaden the sound I suppose.  I have seen/read, where some folks have used the extruded foam board and glued their track directly to it, but I have never opted for that approach.  Hope that helps.  Bo

Plywood then the homasote.

Thank You Much, Fellas!

                                        -Bob

I just wanted to add that the trick to deadening sound is to avoid hard surface to hard surface contact.

Hard surfaces can be the track, the plywood surface, the benchwork frames or even structures. Complicating things however is Blue/Pink foam can also be considered a hard surface. Now foam (foamular) can be a good sound deadener if you are careful with how it's used.  If you don't take proper precautions and fully secure the foam to the plywood (it really shouldn't be used without plywood under it for O gauge) surface the foam can actually act like a drum and make the layout louder so I advise against using it unless you are prepared to glue it down fully.

Homasote, as much as I hate to work with it, is great in that it is a soft material so it absorbs sound well. The downside however is it creates a lot of dust and that dust is particularly bad for your lungs. You can cut down on the dust by cutting it with a knife but that can be time consuming and you will go through a lot of blades.   One additional concern is Homosotes tendency to absorb moisture and bubble up between screws over time. This I've found can be combated by placing screws every 6 inches on a grid but that takes time and a LOT of screws. 

I have theorized that a surface built like a sandwich would be the best way to mute unwanted noise. my thoughts are if you placed homosote on the benchwork frame in strips followed by a plywood surface and then another layer of plywood it might work better than plywood attached to the benchwork frames alone.   Another sandwich I'd like to try is to secure a sheet of homosote or perhaps a sheet of 3/4 Foam to the bottom of the benchwork with the top being a typical 1/2 plywood with homosote over it.  In any case all layouts benefit from a quality fabric skirt which works very well at keeping noise under the layout. 

Do we have some where in this vast amount of information (forum), just how much sound reduction this application provides????

And then made changes to the wiring?

I don't understand why people bother with the expense and effort of plywood under homasote.  I built a layout in the 1990s (now gone) where I put homasote directly on the benchwork, did not use plywood at all.  It worked fine, did not warp and was up for over ten years, and it was very humid in the summer.  I did have supports on perhaps 24" centers. 

Bill

Your placement order is correct.  The plywood goes on the bottom, then the styrofoam.  Just walk by the Homasote in the store.   Your previously built layout using 3/4" extruded polystyrene and plywood was a good choice.  Homosote is made out of the same material that ceiling tiles are made out of.  Take a look at the ceilings in your area.  Do you see any sagging tiles?  About 75% of the ceiling tiles in my ofice are sagging.

I believe Lee Willis did some kind of testing and posted his results, but that was like 2 years ago.

Doubtful. The issue is more price than anything. I could see the benefits of a one inch open cell foam application before wiring the layout but Spray foam is still too expensive to be a viable solution.  If someone were to try it I'd recommend wiring the layout after installation as the foam is easier to drill through and scrape away to install drops and switch machines than it would be to dig through the foam to find and fix a wiring issue later on. 

Hope you don't plan on walking on top of the layout!

I had experiences with homasote on a club layout years ago. It wasn't so handy for all the hand-laid HO track we put down. Ties tended to split and joints in the homasote weren't always level.

I've never bothered with homasote or cork etc on my other layouts, including O-gauge. I don't see that the noise is such a big deal; it's not like I run trains all day long.

Plywood then homasote,glued to plywood, screwed down to make sure it bonds in all areas. Remove screws when dry and paint before applying scenery, NO moisture problems.

Homasote is made from old ground up newspapers. Get knife blades for your saber saw and it cuts great and quick.

I was looking into Homasote as well but a friend turned me to QuietBrace (Home Depot).  I put the table frame with 2x4's then 58" plywood followed by the QuietBrace.  The big hint of the year was to use the Bosch T113a jigsaw knife for my saber saw.  WOW, what a combo.

I am in the process of painting the QuietBrace and looking forward to a quieter, better layout.  Thanks to Alex for the great tips.

2012 and it was working on Lionel Fast Track before he wound up tearing his fasttrack out because of loss of Electrical Continuity because of a Cleaner.

ChefTed,

   You will love the quiet brace, it actually deadens sound to darn much.

My wife still likes hear the trains run.

PCRR/Dave