If I build, say, 2 x 4 table top benchwork, and trim it with 1x stock so it stands up proud of the surface about 1/2 inch on the long edges (making sort of a tray) and then place 1/2 inch Homasote in the tray, is there really any need to secure the Homasote to the tabletop? (Homabed roadbed would go on top of the sheet Homasote and be attached with caulk, as will track to the Homabed.)
The 2x4 Homasote sheets would be held in place by the trim along the long edges and each short side of Homasote as the tables abutt each other along the wall.
My new layout looks like it will be in an under-house garage that is used primarily as a rec room. While it is insulated and has a duct for minimizing extreme heat and cold, I wouldn't call it climate controlled. Temperature swings may not be an issue, but I expect some seasonal humidity changes here in Georgia. Movement of 1x and ply benchwork is expected to happen at least some. If the benchwork moves but the Homasote, (and roadbed and track attached thereto) is unattached, it shouldn't move with the table, IMO.
Also, the lack of attachment would tend to isolate drumming vibrations from reaching the plywood.
I'm thinking there are a couple of advantages to just letting the weight of the Homasote and the 1x trim hold it in place within the 2x4 trays, and can't think of any real problems by not securing it.
Thoughts?
- Douglas
You don't say whats on the bottem of the tray,or I missed it.Homasote can't span very mutch.
but like you said, where is it going to go? If there was 3or4 small pieces ,then perhaps, maybe,. But one solid piece should work.
Was it me, I would use a sheet of foam,
Here's what I know. Homosote, glued to plywood with all the rail joints soldered with eventually lead to kinked track. The glue is sufficient to hold the homosote without separation from the plywood.
Either the Homosote expands and contracts or it is stretched and shrunk by the underlying benchwork.
Here's my guesses, homosote does expand and contract because it is a paper product
It would be a coincidence if it was exactly the same as plywood, but I'm not sure that would matter.
An individual piece of homosote, would have more force weighing it down that it would holding it to the adjacent piece, so that pieces would tend to move independantly. That would tend to separate rail joints or kink rail depending on how each individual piece was moving and expanding compared to the next piece.
I think you are creating tectonic plates
Henry
COB Potomac & Northern
Shenandoah Valley
I've only used Homasote on previous layouts, as track bed, so I can push in the nails/track spikes, so I have no experience as how it relates to weather, with warpage, curling on the corners, etc., but I think I would still drive in a few dry wall screws, maybe in the corners, to keep it flat.
I really don't know about any "drumming" effect, I've put track right on plywood, Homasote, foam, and heavy cardboard on top of foam, and you always get track noise.
I will say, that with the heavy cardboard as track bed, on foam, the non-ballasted hidden track on my layout is the noisiest. The ballasted areas are the quitest.
Mike.
My You Tube
Henry, what you say could very well be true,but the man is talking about a 4ft span, I really don't think it would move that mutch if at all.And he would have'' built in'' expansson joint every 4 ft.
Mike makes a point I didn't think of; cornors curling.I admit I never worked with that product. But knowing what it is,curling could happen.But if it did; a well placed screw would take care of it. Foam don't curl.
I use 1/2" Homasote on top of 1/2" plywood. I glued mine down with Titebond glue, then used 1" screws to hold it together for about 2 weeks before I removed all the screws. This winter was really cold a few times (-17 w/-24 wind chill was the lowest). Anyway in my heated basement the Homasote pulled away from the plywood in over a dozen areas.
I think the issue was expansion and contraction difference between the paper and wood that caused the issues. I wound up permanently rescrewing a lot of the areas to hopefully alleviate that issue.
Joe
The old hands in my area say you should leave Homasote in your basement for a full cycle of seasons before using it. Also that you should varnish it on all sides and edges after cutting.I've used both Homasote and foam. I will never use foam again. Rotten garbage.
Disclaimer: This post may contain humor, sarcasm, and/or flatulence.
Michael Mornard
Bringing the North Woods to South Dakota!
When I started building My layout in 1980, it was made in sections, 3 and 4ft wide, two lengths of 6ft and 10ft. Made out of #2 kiln dried pine, cut by myself into 1x3's which all joints were glued and screwed with galvanized dry wall screws. The base was exterior 1/2 one side smooth plywood. On top of that was 1/2'' Homasote, not the take-off Homasote, but the real Homasote which has a Homasote stamp on it, (it is a trademark) fastened down with just galvanized screws. I don't know where people come up with this drumming idea from, but I don't have that problem, what so ever. The layout is mostly made open grid, no grades. In all that time I have not experienced any movement from expansion/contraction. I have since taken out sections and installed in one of My Son's basement for His Son's an ongoing project. The sections taken out and reinstalled are just as firm as the day built. The layout was 12 1/2 x 40 x 12 1/2, 3 cab double track mainline. It had just become too large for one elderly person (Me). All the sections were bolted together with carriage bolts. The beginning plan was to eventually move and layout made to be taken apart..........didn't work out that way........I'm still here...everyone else is gone, 38 yrs. later. LOL
Foam is for scenery........But thats My opinion and where the drumming idea started from.
Good Luck!
Frank
Thanks so far.
Yes, bottom of the tray would be adequately supported plywood.
Even though the table sections would be 2x4, I would secure two together lengthwise and use a big 2 x 8 section of Homasote.
As far as expansion, my thought was that wood and Homa might expand at different rates. So not attaching them together would avoid any problems caused by two substances fighting each other.
I hadn't thought about curling at the corners.
I figured Homasote would lay flat, but being a paper based product it might rise up in places?
Like I tried to say in My post.......Homasote is a registered name brand and If that is what You are going to use....You will not experience any of the problem's that people say will happen with Homasote, simply because there are other Mfg'ers that have a similar product and call it homasote......but it really is not Homasote.
All you need to learn about it....do a little searching on the site: Been using it since the 60's and never had any problems with it.
http://www.homasote.com/applications/hobby
Take Care!
zstripe Like I tried to say in My post.......Homasote is a registered name brand and If that is what You are going to use....You will not experience any of the problem's that people say will happen with Homasote, simply because there are other Mfg'ers that have a similar product and call it homasote......but it really is not Homasote. All you need to learn about it....do a little searching on the site: Been using it since the 60's and never had any problems with it. http://www.homasote.com/applications/hobby Take Care! Frank
Thanks Frank. Your post didn't specifiy if your layout was in a semi-climate controlled space that might have some humidity swings.
The drumming I am talking about is when the "noise" threads come up, a few usually mention that vibrations from the trains can be transfered to the plywood via screws, making the homasote or foam or whatever not a good sound insulator. If you have not experienced that, then that's one factor in favor of me using a few screws.
OTOH, if Homasote works fine by just setting in the tray then there's no need to secure it any further.
I'll have to look around to make sure I get the proper Brand and not a knock-off.
DoughlessYour post didn't specifiy if your layout was in a semi-climate controlled space that might have some humidity swings.
Douglas,
I live in the Midwest, Chgo burbs. Layout is in attic, started at the same time I was finishing same. Did all the work Myself. 1990 I put in Central Air.....so for 10yrs. it had all kinds of variations concerning weather. House has a crawl space...can't have a basement in the area, high water table.
That link if You browse around on it will tell You what to use and when for fastening down the homasote to any material, glue, screw, nails etc. It will even show you where to put the screws or adhesive with diagrams.
Also if You read some uses for it...it will clearly tell you it has sound deadening qualities and in some cases waterproof.
Homasote moves with humidity changes just like any other wood based product. Its' rate of movement is somewhere between most plywood and solid wood depending if you are talking along the grain or across it. High humidity or low humidity will not be a problem. Extreme changes in humidity is where issues can occur but that is also true of plywood or solid wood as well. If someone says they need to seal Homasote to keep it from moving, do they seal the underlying benchwork as well? Why not? It has the exact same issues that the Homasote does. In answer to your question I think I would attach the Homasote with drywall screws and eliminate the complexity of the tray construction. Sound transmission is a huge and complex topic but for this dicussion, generally as long as there are not fasteners that penetrate from the track to the ply you should be okay. Attach the track to the Homasote and the Homasote to the ply just make sure the fasteners are offset.
Steve Cox
Cascade Rail Supply
One other thing, if it says Homasote, it is Homasote, that is a trademark. The company is in New Jersey and all product is manufactured there. Homasote is a medium gray color. Most other generic "sound insulation" boards I have seen tend towards brown in color.
Douglas -
I faced this decision recently on my small layout I built. Ended up using a 1/2" plywood base, with a sheet of Homasote on top. No glue, just drywall screws all around. The plywood sub-base is screwed to Sievers Benchwork modules. They in turn are bolted together with carriage-bolts. To add some rigidity, I then outlined all the modules with 1x5 lumber, also carriage-bolted to the outside of the modules. I could park my car on it...
As to locating real Homasote, my local Home Depot carried it.
Think I paid about $30 bucks for a 4x8 sheet.
My local Lowe's does not.
Hope this helps!
Mike
Mike,
Locating Homasote in a big box store seems to be regional. East coast Home Depots carry it, west coast ones do not. Menards does I believe but if you are not in their region or on the east coast big box stores won't be much help.