Frost Line Depth

[Panakk]

I dug a few holds to pour a footing on my deck. The ruling is that the hole should be 12 in wide and 36 inches deep (i'm assuming that's 6 inches below the frost line) since that the general rule.

On a couple of the holes i couldn't get more than 32 inches deep. Will that be bad? I even have one hole where it's only 24 inches deep since i hit this gigantic rock that i can' budge.. What are your thoughts? I have 9 holes, for a 16x20 deck. Do you think i'm fine?

 

[Eli]

I'm not really sure you want to be trusting the structural integrity of your deck to ATOTers.

 

[InverseOfNeo]

Originally posted by: Eli
I'm not really sure you want to be trusting the structural integrity of your deck to ATOTers.

:beer:

 

[Panakk]

Originally posted by: Eli
I'm not really sure you want to be trusting the structural integrity of your deck to ATOTers.

I thought so too but i'm sure some of you have done this before.

 

[Mo0o]

Maybe you can just add a couple of more holes. Then again im talking out of my ass so you probably should'nt listen to me

 

[Panakk]

Originally posted by: Mo0o
Maybe you can just add a couple of more holes. Then again im talking out of my ass so you probably should'nt listen to me

i already have 9 holes

 

[Sundog]

Did you not take out a permit for this?

Call up the inspector and ask. You do NOT want to be above the frost line. This could cause one or all of the posts to heave at different rates---->not good.

A house near us built their footings well below the frost line and 2 winters ago we had frost the extended well past what it normally does. Their deck heaved up in two posts, not good considering their deck posts were also attached to the roof of the house (the roofline extended over the deck).

 

[Panakk]

Originally posted by: Sundog
Did you not take out a permit for this?

Call up the inspector and ask. You do NOT want to be above the frost line. This could cause one or all of the posts to heave at different rates---->not good.

A house near us built their footings well below the frost line and 2 winters ago we had frost the extended well past what it normally does. Their deck heaved up in two posts, not good considering their deck posts were also attached to the roof of the house (the roofline extended over the deck).

I didn't get a permit because it's so low of the ground (2ft) and you don't need it for a deck that low. I have designed every aspect of the deck based on design guidelines for a deck that sits 14 feet of the ground. I've pretty much overengineered the deck.

The ruling here is to have the footing be 36 inches deep. I have most of my post 36 inches deep. Except for one where it's 32 inches and one that's 2 ft because ther'es a large boulder in place.

I have 14 inch holes, so i'm not worried about my footings moving. I have been surfing the web and found out that the frost depth here is 30 inches, i just want to make sure i'm right, or else i got to go back to digging.

 

[DrPizza]

Sounds like you are just pouring the concrete directly into the hole?
Where you're running into the big rock, you can always make a larger hole so that you can easily remove the rock. It won't be too hard to do so. Then get one of the tubes for concrete at your local hardware store. I'd definitely go farther on the 24 inch hole, you may survive the other ones.

 

[whoiswes]

i see you live in KC - me too (well, KCMO, actually...)

i don't think it gets cold enough down here to warrant worrying about the 32" holes, but the 24" might cause a problem, especially since there is a large rock underneath it - remember stories about fields growing rocks (as the frost heaved the rocks through the surface, each spring there would be a bunch of rocks in a field that had none the past fall).

i would call the local city office and find out what depth code requires. it would be worth the extra time to do it right now, versus having to rip up the deck in two or three years.

good luck!!!