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Deck heaving due to ground water or unstable soil

I have a deck that heaves every winter. I noticed this spring when I dug a hole to the footing on my house that there is water about 4 ft under my house. Not sure if it is ground water but never the less it might have caused my deck posts to heave. Can anyone tell me if this is ground water or unstable soil, how I can secure my deck post footings to make sure it does not heave this winter? My deck is a second story over a walk out basement. My patio also heaved this year as well but I have a plan for that. Please let me know if you have any other questions. Any help is very appreciated as I do not want any more damage to my deck or home!

designseeker
Re: Deck heaving due to ground water or unstable soil

Water will be the highest in spring.

Later in the summer, dig down below the frost line
and extend the footing. If the bottom of the footing can rest
on solid soil, it won't heave in the winter. If there is water
down there, some kind of drainage could be installed- Way more
complicated.

http://www.Westchester-Architects.com

Ron remodeler
Re: Deck heaving due to ground water or unstable soil

Water doesn't cause heaving frost does. Most water doesn't freeze under ground unless pretty close to the surface or within the frost line.

The frost line, where the frost reaches down in the soil in winter, is your main concern, then soil type creates your thinking path for the type of footing size and preparations.

The porch footings should be below the frost line in your local area, perhaps 4 feet. they should be on stable , solid ground. If your soil is wet, muddy and prominantly silt or clay you will need larger footings with crushed stone under them. Don't be afraid of the water be concern with the soil, the depth and what is the best way to allow water movement soil stability and footing size and depth.

Your walk way may have issues with the soil and water content of that soil.

Re: Deck heaving due to ground water or unstable soil
Ron remodeler wrote:

Water doesn't cause heaving frost does. Most water doesn't freeze under ground unless pretty close to the surface or within the frost line.

The frost line, where the frost reaches down in the soil in winter, is your main concern, then soil type creates your thinking path for the type of footing size and preparations.

The porch footings should be below the frost line in your local area, perhaps 4 feet. they should be on stable , solid ground. If your soil is wet, muddy and prominantly silt or clay you will need larger footings with crushed stone under them. Don't be afraid of the water be concern with the soil, the depth and what is the best way to allow water movement soil stability and footing size and depth.

Your walk way may have issues with the soil and water content of that soil.

Exactly, well said Ron!

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