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please criticize my floor plan!

Lewisthepilgrim

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Joined
Dec 9, 2011
Messages
91
Location
seacoast NH
Hey guys what's up ? Prepping for a floor pour soon.

20x22 garage. Floor is currently all sand with random rocks and gravel. We are just finishing up leveling with another 2 yards of fill sand. Next we'll rent a compactor to compact the sand before putting down 6Mil polyethlene vapor barior. Then 2'' XPS Foam from lowes https://www.lowes.com/pd/Kingspan-I...d-Polystyrene-Foam-Board-Insulation/999972968

After The foam is down, I'll get some Rebar. Probably the bigger 1/2'' stuff and lay it out in a grid. How close should I lay out the rebar??

I plan on going 5 Inches thick with 3,000psi concrete poured right over the XPS Foam board

any recommendations??

I plan to install a 2 post lift at some point in the future.

Heat source will be an overhead Radiant tube heater, and probably a minisplit in the summer for AC also!

I only plan on heating the garage when I use it after work every once in a while, and on weekends.

Should I get any sealant additives added to my concrete?? I don't plan on finishing it at all afterwards...
 
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Chris705

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Nov 1, 2012
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834
Location
The Finger Lakes of NY
I’d say you’d be ok at 18” oc for your rebar grid using the #4 bar.... optionally look at #3 bars at 12”....not sure one is really better than the other.... Be sure to read LLWillysfan’s thread on slab placement!!!!
 

Candoo

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Joined
May 13, 2011
Messages
52
Create a depression 3 ft by 3ft and 12 inches deep for your two post. Bend rebar so that no rebar is within 6 inches of the surface. This will give you a proper base and eliminate the chances of hitting rebar when drilling for your anchors.
 

ZRX61

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Joined
Aug 15, 2006
Messages
28,716
Location
Solar Blight Valley, SoCal
ok, since you asked so nicely:


It *****, looks like it was thought up by a 5 year old, will most likely be condemned by the planing dept before you even get it painted, contractor will probably just take off with the money.



How's that? (btw, I didn't actually read your plan, I was just responding to your request for criticism )
 

ConCretin

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Joined
Jan 20, 2011
Messages
3,378
Location
Central Maine
Honestly I think your plan is fine but since you asked.......

I'd skip the insulation. For an infrequently heated structure as you describe, the payback is measured in lifetimes. My theory is that for a structure that is not heated full time, underslab insulation does more harm than good. It provides minimal benefit from downward heat loss while it blocks the heat from the earth that would otherwise keep it a few degrees warmer the rest of the time.

I wouldn't bother with rebar. It won't make the floor any stronger and properly supported wire mesh will hold any cracks together just as well for less money.

I'd spend what I saved there by upgrading to 4000 psi concrete. You don't need it from a structural standpoint but the added cement will provide a more durable surface and provide some margin for error during finishing.

Finally, I'd spend the rest of my savings on a 15 mil vapor barrier instead of the 6 mil poly. If you ever decide to coat the floor, it will truly limit vapor migration.

Not trying to be a horses ****. Just providing food for thought. Good luck with your project!
 
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Zevo

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Joined
Nov 4, 2017
Messages
39
Make it bigger. I’d think 4 feet wider and 4 feet longer would make a big difference without breaking the bank.
 

Gotcha640

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Joined
Jan 27, 2015
Messages
948
Location
Houston TX
What will you be using the space for? Apparently at least one car, if you're doing a lift, but will it be one lift bay, one daily driver bay?

Doors?

Will you be doing any kind of built in cabinets/counter space?

Those kind of plans could point to different dimensions being more helpful.

Any drains or plumbing?

Does anyone do embedded anchors for lifts? I always see drill and epoxy anchors in home retrofits, but in the plant it would be embedded anchors on a new build.
 

GMCGarage

Well-known member
Joined
Jan 31, 2017
Messages
1,264
Hey guys what's up ? Prepping for a floor pour soon.

20x22 garage. Floor is currently all sand with random rocks and gravel. We are just finishing up leveling with another 2 yards of fill sand. Next we'll rent a compactor to compact the sand before putting down 6Mil polyethlene vapor barior. Then 2'' XPS Foam from lowes https://www.lowes.com/pd/Kingspan-I...d-Polystyrene-Foam-Board-Insulation/999972968

After The foam is down, I'll get some Rebar. Probably the bigger 1/2'' stuff and lay it out in a grid. How close should I lay out the rebar??

I plan on going 5 Inches thick with 3,000psi concrete poured right over the XPS Foam board

any recommendations??

I plan to install a 2 post lift at some point in the future.

Heat source will be an overhead Radiant tube heater, and probably a minisplit in the summer for AC also!

I only plan on heating the garage when I use it after work every once in a while, and on weekends.

Should I get any sealant additives added to my concrete?? I don't plan on finishing it at all afterwards...

Is the rebar for strength or crack control?
 

NUTTSGT

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Staff member
Joined
Sep 14, 2009
Messages
50,870
Location
Northern Central Ohio
Heat source will be an overhead Radiant tube heater, and probably a minisplit in the summer for AC also!

I only plan on heating the garage when I use it after work every once in a while, and on weekends.

..

Only heating to a certain working temp like 65 or a minimum temperature like 50 ?

Once you get that concrete warm, it'll stay warm easily when the building is fully insulated. If you turn the heat "on" from completely off, it'll run longer trying to warm the place up with a huge cold concrete floor.
 

ConCretin

Well-known member
Joined
Jan 20, 2011
Messages
3,378
Location
Central Maine
great ideas thanks guys! Question, How should I do my expansion joints??

For a 20 x 22, I'd be looking to control shrinkage and avoid control joints altogether. If you're not comfortable with that approach, one each way should be more than adequate. Groove during finishing or sawcut immediately after finishing with an early entry or soffcut saw for best results. Joint depth should be a min of 1/4 of slab thickness in either case.
 
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