Depth of footings for porch

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Thinking about replacing an old porch this summer. Central Wisconsin.
What is recommended depth for footings of corner posts?
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If it is just a deck not attached to the house with a roof over the deck I dont think you need to worry about depth you need only to support the weight and keep the deck from sinking. I used flat 2" concrete block, the deck has been fine since 72
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On Tue, 01 Apr 2008 10:02:24 -0700, ransley wrote:

It's attached. Soil is sandy loam..
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By atached I meant a porch with roof. Go ahead dig down 4 ft and have fun but all you need is a pad, and wood should not touch concrete but should be bolted to special plates to keep it from rotting that keep it off the ground.
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Below the frost line and to solid ground.
Might be 50 feet in a swamp- but in relatively stable ground, just get below frost.
If you're pouring concrete, don't forget to make the base large enough.
Jim
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On Tue, 01 Apr 2008 13:03:56 -0400, Jim Elbrecht wrote:

Soil is sandy loam.
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For me frost depth is 3 feet, my porch has been fine 35 years set at ground level on block, a 25 x 30 foot deck, so to just say below frost line is BS
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-snip-

To me, a deck is not a porch. You can attach a deck so it slops up and down with the frost. [I wouldn't- but you could] A porch needs to be rigid so the roof doesn't rip away from the side of the house.
If it is on bedrock, there isn't any frost heave, so you can get away with more.
But if it was mine, I'd go below frost and not have to revisit that job. On sandy loam I'd also want a huge elephant foot set on compacted crushed stone.
But that's just me. If there will be a permit involved, the only person that can answer the OPs question is the OPs building inspector.
Jim
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franz fripplfrappl wrote:

wrap the Sonotube in polyethylene to help keeping it in place in the face of frost heaves. Most decks don't weigh enough to keep a straight footing in the ground when there are frequent freeze/melt cycles.
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Sonotubes, yea right, bs , if he is building an addition ok, but this is a dam Deck, nothing more. Even small sheds you buy are recomended to have Pads, not foundations to frost. A fence yes, but not a deck.
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on 4/1/2008 1:35 PM ransley said the following:

He is in Wisconsin, and he says the deck is attached to the house. If the deck is attached to the house, it needs support starting below the frost line. Having a deck on surface pads heave a half inch or so during a Wisconsin winter will certainly un-attach the deck from the house, over time.
--

Bill
In Hamptonburgh, NY
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On Tue, 01 Apr 2008 14:07:21 -0400, willshak wrote:

It's a porch, NOT a deck.
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On Tue, 1 Apr 2008 10:35:11 -0700 (PDT), ransley

The reason sheds are allowed to have pads is because they float up and down & it doesn't matter.
Presumably the house stays in place because it has a foundation. If you attach something rigid to the house, it must not move up and down or it will pull itself away from the house.
Jim
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Why not its a deck, and mine is fine after 35 years doing it, You dont have doors or windows to worry about I still say its overkill as I have had no problems. If it had doors or a roof attached to the home then it would need piers.
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On Tue, 01 Apr 2008 10:35:11 -0700, ransley wrote:

It's an attached porch with roof. Not a deck! I never mentioned deck. No idea where this came from.
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Go take out a building permit, like required. And while you're there you can ask the building inspector. He/she may not give you an answer, but an architect will.
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Sorry, I thought Deck, a porch with roof needs support below frost line.
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franz fripplfrappl wrote:

Around here the building inspector has taken a liking to the earth screw ground anchor. Screw down below frost line. I used them for my decks a few years ago. No movement at all.
The link just shows the general idea.
http://gmesupply.com/index.php/cPath/13_278?gclid=CPKFyrzkupICFQq0HgodQGaVYA
The anchors I used had a threaded end and a adjustable bracket for bolting to the wood.
They're called ground hogs around here. Home Depot has them.
LdB
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I am in SE Wisconsin, and I believe that my local inspector made me go 42" deep here, but it could have been 48". Should be about the same for you in Central WI, but you should probably verify with your local building dept. I would be willing to bet that it will be 48" or 54".
JK
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On Tue, 1 Apr 2008 19:18:49 -0700 (PDT), Big_Jake

Here in Iowa that's about what it is too. It is because the inspectors want them to be below the frost line.
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