Installing support posts in dirt floor garage

[Squeaky_Alexander]

Hi, I'm wondering how much of a concrete base I should have for putting in support posts in my dirt floor garage. It's 24x20 with one temp support beam in there now. I've had folks tell me I would be fine with a 2x2 or 3x3 block block of concrete under a 6x6 post, but I'm in Vermont and am wondering if maybe I should be digging down past the frost line and maybe doing a 4ft concrete tube. On the other hand a normal garage pad is ~6 in, although I guess that usually isn't load bearing. Thoughts?

Oh, the other thing is the support beam running across is kind of cobbled together. Wondering if I should put something like a 2 or 3 ft section of a 2x6 flat under this beam as more reinforcement. Or maybe a metal plate?

Thanks for any thoughts.

 

[Bondo]

Ayuh,.... Go to yer local precast concrete supply house, 'n get yerself a "Camp Pad",...

They're either 18" or 2' diameter, 6" thick round pieces used for huntin' camp foundations up in yer country,....

 

[ozyborn]

Without knowing your building codes. I would dig down 48", bell out the bottom. Pour a concrete footer. Then support post on the footer

 

[readhead]

Not much chance of freezing inside the garage. 2'x2'x12" inches deep would probably do the job. Better solution would be to replace the beam with something that wouldn't require a post.

 

[ard]

Not much chance of freezing inside the garage. 2'x2'x12" inches deep would probably do the job. Better solution would be to replace the beam with something that wouldn't require a post.

Possibly a good point- however if it is an unheated, uninsulated, thin-skinned building might it not freeze inside? Upstate Vermont?

I guess also one would wonder what footing depth is on the perimeter of this building?

 

[rburke65]

Well I wouldn't be afraid of a 2'x2'x12" deep base for your post.

 

[Squeaky_Alexander]

Thanks for the feedback - I'm a new homeowner as of ~6 months ago so it's useful to get some perspective.

Would love to just replace the beam with something that doesn't require posts but we have so many projects that I think I just want to keep this one simple.

I tried finding VT code but the PDF I found on the state website didn't seem like it addressed these specifics. Oh and I'm in southern VT, family in NW CT often has similar weather.

Sounds like a 2ft pad will be fine for this application. It's going to be fastened to the support beam so unlike with a deck frost heaves shouldn't be an issue? And yeah, garage isn't insulated. Could be ~100 years old as my house was built in the 20's..

 

[John in OH]

Remember, the ground temperature below frost line year-round is about 55F more or less. So, in a sheltered area such as inside of an unheated building, the heat from the sub-soil will "heat" the soil "higher", ie., the frost line will be much shallower.

If I were faced with this task, I'd probably hand-dig a hole +/- 30" deep and about 18-20" in diameter. Mix up three or four 80# bags of Sakrete in a wheelbarrow, pour them in the hole, level off the top of the concrete with a hand trowel or small float, and let it set. After a day or two, set the post and back-fill the hole. The bottom of the post should be ON the concrete, not IN the concrete.

 

[Firebrand]

Being 45 miles north of the MA/NH border, I can strongly recommend going down 48" for your footer as a proven method to beat the frost line. Did just that in my own garage project about twenty years ago. Same setup and slab still doing well.

 

[Squeaky_Alexander]

Got these posts installed, am happy with the outcome. Thanks guys!

Garage is frickin mess but the posts (I think) look good.

 

[xyster101]

How deep did you go?

I am in Albany NY and footers are 42" here.
I hope you took the extra 20 min to dig past 24" to 48".


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