OT deck footings

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plowhand

Member

• Apr 18, 2020

• #1

I live in MN and in the spring of the year the footings/posts on my deck heave up..What is a way to solve this problem thanks in advance.

 

544hydro

Member

• Apr 18, 2020

• #1

Do you know how deep they are?

 

JoeM(GA)

Well-known Member

• Apr 18, 2020

• #1

Sadly deeper footings below what ever your frontline is is the only way to stop it. I?d bet that?s 5 or 6? in your neck of the woods

 

JoeM(GA)

Well-known Member

• Apr 18, 2020

• #1

Make that frost line, I hate things that automatically correct

 

544hydro

Member

• Apr 18, 2020

• #1

The Minnesota State Building Code requires footings to be a minimum of 42" deep in the southern part of the state, and a minimum of 60" deep in the northern part of the state.

 

OP

OP

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plowhand

Member

• Apr 18, 2020

• #1

I would say minimum builder had
to go 20"

 

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tomturkey

Well-known Member

• Apr 18, 2020

• #1

Even if you had your footings at or below frostline you may get heaving. The soil can grab the pole and as the ground heaves push the post with it. That freezing soil in the northland does some strange stuff. gobble

 

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Greg1959

Well-known Member

• Apr 18, 2020

• #1

Use these and don't worry about it.....

 

Geo-TH,In

Well-known Member

• Apr 18, 2020

• #1

I've made many decks for rent property. Some are over 20 years old.
Many on YT will tell you not to put concrete around post. I made a little bridge and post were concreted back in 1996. Still there.

Not one concreted post failure. Had to replace deck boards. Done nothing to posts on anything.

I put a treated post in the ground, back filled with dirt and in ten years part of post underground was gone.
An alternative would be to dig hole, fill with concrete, attach metal post bracket to rebar
George

 

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marloweg

Well-known Member

• Apr 18, 2020

• #1

i never put post in ground if it's clay or every high water table

 

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David G

Well-known Member

• Apr 18, 2020

• #1

Put the bottom below frost line, which is probably 6', and pack some gravel around them.

 

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David G

Well-known Member

• Apr 18, 2020

• #1

Put the bottom at 6', ever better, flare the bottom, they will never move.

 

showcrop

Well-known Member

• Apr 18, 2020

• #1

Around here all the builders use concrete bell piers. They are 2ft at the bottom and around eight inches at the top. usually four feet deep.

 

DoubleO7

Well-known Member

Location

Crystal River, FL

• Apr 18, 2020

• #1

What happens when the deck heaves?
Does it twist up like a pretzel?
Rip the side of the house off?
Cause all the nails to come out?

 

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Stephen Newell

Well-known Member

• Apr 18, 2020

• #1

The posts heave up because the ground swells. It would be difficult to fix now but when you build a deck if you would sink the posts deep in the ground in concrete it would be below the surface swelling. At this point you need to find a way to keep the ground dry under the deck.

 

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Willow Lane

Member

Location

Central Maine

• Apr 18, 2020

• #1

Look into screw pile, basically a spiral plate on a rod, screwed into the ground until the plate is below frost level.

 

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steve_in_mo

Well-known Member

• Apr 18, 2020

• #1

Depending on clearance/headroom, he might be able to
jack up the deck, pull out the supporting posts, run
an augur into the ground, and install the concrete
filled tubes below frost line.

 

Blackhole49

Well-known Member

Location

White Lake MI

• Apr 19, 2020

• #1

At 20" in MN, I would just make sure it is not attached to the house and let it float. When it becomes unusable, remove and build right.

 

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Duner Wi

Well-known Member

• Apr 19, 2020

• #1

As showcrop said, Bell pier. Here is picture if you scroll down a bit.
Used this on add on entry to house and it has never heaved a bit in 60 years.
Get below the frost line.

https://www.decksgo.com/deck-footings.html

 

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rlp in Co.

Well-known Member

• Apr 19, 2020

• #1

I have built a couple of decks. The first one I dug post holes and then set posts in the holes and then poured concrete around the posts. After the concrete set up, the post swelled up and cracked the concrete. Not so good but the deck is still good in spite of that. The second deck I built, I just used the concrete bases that set on top of the ground. I figured that I might have to adjust them but they have been good for about 5 years now.