Homasote necessary with cork roadbed?

Not really. It's a matter of how much sound deadening you need. Homasote holds track screws and doesn't transmit the vibrations into the plywood. However, using screws that go through the Homasote into the plywood will defeat the purpose. We've found that cork on  plywood is fine.

Thanks Matt. So then I should screw the track into the cork, but not all the way down into the wood substructure correct? Glue the cork to the wood, and then screw the track into the cork?

If you're going to ballast your track, then the screws are only temporary. The glue that holds the ballast will also anchor the track.

Dennis Brennan

Man, you're gonna get lots of opinions on this one. Required? NO

I used Homasote as a base over my entire switching layout, then another level of homasote to raise the track as the actual roadbed. I also used cork on top of the base homasote in some areas just to change track elevations. My homasote roadbed is screwed into the base layer of homasote. I did not screw any of my track down though, I used brads instead. I didn't want any ugly screw heads showing. The brads are practically invisible.

These are cell phone pix but if you look hard enough, you can find the brad heads sunk down in the ties. I am very pleased with the sound level, even after the ballast went down.

That's it. Dennis is right about gluing ballast. It will hold track pretty well, except maybe tightly-bent Atlas flex. We had to do a realignment and had to use denatured alcohol to dissolve the ballast holding the track in place (it also attacked the cork underneath.)

I just put down 46 sheets of QuietBrace and am very happy with it. About 1/3 the price of homosote and holds screws better. A terrific sound deadener.

The product is described in this thread

Dale H

We had to do a realignment and had to use denatured alcohol to dissolve the ballast holding the track in place (it also attacked the cork underneath.)

Matt,

What bonding agent did you use to secure the ballast? Regular white glue will easily loosen up with a water.

Before doing any scenery or laying track, I always paint everything, as well as any cork, with brow latex paint to seal it.   

Dennis, how does painting the cork help? Just curious. I've heard of painting homosote but not cork.

Laidofsick your track looks great!