bertrandsv87

iTrader: (2)

Good subfloor pictures guys, but my worry is how is it going to hold up when an obese Marshall tries to run on it, and falls hard???? Should we tech the Marshall's weight...lol... 240lbs maximum!!! I know BERT won't pass tech ....lol.... Will you????

dave-man

iTrader: (21)

Here are some in progress pics and finished product pics.

RedBullFiXX

iTrader: (34)

Good looking track there

jlfx car audio

iTrader: (37)

I wouldn't ever just do one 3/4" layer of osb for a lasting rc track. Moisture from the concrete will soften the wood and all it to flex more over time which will make the carpet bubble up. With 2layers of 1/2" osb overlapping at least 2' and making sure all seams are offset will keep the wood from flexing as much which keeps the carpet from bubbling up as bad at any given joint

theproffesor

iTrader: (66)

Please explain the reason for placing the 2x6' flat. I dont get this. There stregth come from the vertical.

If they were vertical and elevated 6-10" high, supported by 4x4 risers every 48", placed on 16" centers, they would support a real car. So there is no need to worry about a tunmarsal tripibg and causing damage. The way you have it pictures there, there is almost no airflow under the floor. Of course moisture will be a problem. If elevated, then air could flow and moisture would be a non issue.

Please explain the structural engineering reason behind the method being used here. Or is this just another case of "thats what we saw someone else do"

But I do like how the edges between the osb are smoothed.

Josh Hohnstein

iTrader: (3)

Yes the strength would come from the vertical but that is a non issue because there is a solid concrete floor under the 2x6's........They can not flex and they offer more surface area when laid this way.

jlfx car audio

iTrader: (37)

Also allowing for screws to be a little off without worry of missing the 2x plus it will keep it from ripping the edges out of the osb if the floor does flex for whatever reason . I will say I feel that 2x6s are overkill but who cares .

theproffesor

iTrader: (66)

Im still not convinced this is a good system. If stregth wasnt an issue, then why the need for so much overlap. The 3/4" or so from the vertical is all you need on the edge and 16" centers provide way more stregth than is actually needed. Ive never seen 3/4" osb flex on 16" centers (unless rotted) Ive seen joist crack first.

By laying flat your now having to deal with all the imperfections of the concrete floor and having to shim for the single high spot. That is alot of shim work and when you place shims like that, the shim takes thebload from the board and will eventaully give out or crush.

jlfx car audio

iTrader: (37)

Are you thinking of the advantec 3/4" sub flooring that's $40 a sheet, it's great wood for this or anything else but not a rc track when 2 layers of 15/32" osb @$7 a sheet will work just as we'll (just about )

theproffesor

iTrader: (66)

Now thats an argument that make more sense. The stuff uve used isnt $40 a sheet, but its still more than $14 (2 layers of $7 plywood). And 15/16 is thicker than 3/4 so it would support more.

Im still not convinced the flat joist is the way to go. It just seems it actually createsnmore problems than it solves.

wingracer

iTrader: (24)

proffesor.

I get what you're saying but try to understand that the subfloor is sitting straight on the concrete. The only reason for having the subfloor at all is that gluing the carpet straight to the concrete (something many tracks do) can be problematic. It's much easier to work out any bumps or level issues with a wood floor than concrete. Also the changing moisture levels in the concrete itself can cause the track to be inconsistent. All those 2x4 or 2x6s are there for is to create an airspace and give you something to screw the floor down to. They are not really structural in the sense of a conventional floor joist.

That being said, I could see warpage being a bigger issue with this design but many tracks are built this way with no issues.

I'm curious. Has anyone ever tried eliminating the joists completely by say gluing rigid foam insulation straight to the concrete and then gluing plywood or whatever straight to that?

jlfx car audio

iTrader: (37)

That I see problems with . Since the screws will not have anything to grab to sink itself into the top layer ,this is if you do the wood 2 layers thick . If you only used one layer I would worry about the glue letting go and allowing the wood to pull up in those areas . Now to help with the wood joists from being in contact with the concrete you could use the thin foam sheets (in strips) under each one .