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wood garage floor?

NutmegCT

Great Pumpkin
Bronze
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Planning a new garage, 18x24. Local regs prevent me from pouring a concrete garage floor.

Would you feel comfortable working under a car (on jack stands of course) on a wooden floor constructed as follows:

3/4" pressure treated plywood, over 8" On Center joists, supported by 4x4 pressure treated timbers sitting on crushed stone.

Local regs say I can't have a concrete pad (and required 42" deep frost barrier) within ten feet of my septic leach field; that makes sense. But regs say I *can* put a wood floor garage in the same area.

I have a small lot. Obviously I'd rather have the full concrete floor - but for some reason can't see living without the septic field.

:jester:

So the question is - would you feel safe working under a car (or jacking up a car) if the floor were constructed as described above.

Thanks.
Tom
 
Thanks Don. So you're ok with the 8" oc joists, etc.?
 
If I remember correctly, my parents garage was 2"x12" joists on 16" centers with tongue and groove flooring..the TR3 was on jackstands for many years on that floor.
 
16" centers. That seems *wide* - but I guess the t/g flooring helped.

I'm thinking 8" centers, to give the added support for the flooring.

Thanks.
 
Good for the Humber getting special treatment.:hammer:

darn right!
(altho' after going through all this, I'll be the one needing special treatment ...)
 
Plan B!

Have you considered pouring a thin concrete floor OVER the wood floor? We did this in our kitchen before setting tile, and it has been wonderful. The guy that did ours made the concrete exceptionally dry, with loads of portland cement, and no gravel at all. It was very different from any concrete I'd ever seen before; it was so dry that it didn't pour and had almost a granular consistency. Supposedly, these characteristics made it much stronger than normal concrete. I'm no expert, but maybe others with more knowledge will chime in.
 
Keith - I'm now up to Plan 9 from Outer Space. (old movie buffs will recognize that one!)

I'd be very worried that the weight of a car - even one as noble as the mighty Humber Super Snipe - would crack that concrete surface, if it's on a wooden subfloor.

T.
 
Joists 8" OC would be super strong as 16" is common. But even that close, I wouldn't like the plywood for jack stand support unless you could be sure there was a joist right under it. Keep in mind that the plywood you get today is junk. Now if you substituted the T&G 2x6 for the plywood as Don-R suggested then even the Hummer should be all right. Another option, if you have to use the plywood instead of 2x6 would be a short 2x12 under the jack stands placed to span at least 2 joists.
 
Keith - I'm now up to Plan 9 from Outer Space. (old movie buffs will recognize that one!)

I'd be very worried that the weight of a car - even one as noble as the mighty Humber Super Snipe - would crack that concrete surface, if it's on a wooden subfloor.

T.

Nevertheless, I've heard of people doing it.
 
I would not want my husband, son or friend to take a chance with plywood no matter how close the floor joints were spaced. Check into what Don suggested and maybe find a contractor or engineer friend that can figure loads before doing anything.

Cheers,
Irene
 
Pavers? Asphalt? Make sure the wood is treated regularly for termites and water.
 
I would not want my husband, son or friend to take a chance with plywood no matter how close the floor joints were spaced. Check into what Don suggested and maybe find a contractor or engineer friend that can figure loads before doing anything.

Cheers,
Irene

What she said.


Jacking applies point loads.

Point loads make stresses skyrocket. (Airliners could be built lighter if it weren't for high heel shoes.)



pc
 
Thanks for all the ideas folks. Regarding the t/g flooring - would it be a problem to put it *over* the 3/4" plywood, instead of *replacing* the plywood?

Tom
 
I'm almost afraid to even think it, but I think we've reached:

plan-b1.png


Details later, but sounds like the wood floor will work. And I've just figured out that I've got up to 19x25 feet to work with.

(scary)
 
hmmm - brick might be a hassle to clean up those oil spills!
 
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