# Fence post heaving



## Canadianboy (Feb 2, 2011)

Hi i need some help I installed a new fence in september and some of my fence post are heaving really bad. i had the fence posts installed by a contractor. They should be about three feet in the ground with concrete. My backyard has poor drainage and am going to put in some french drains this spring but this is nuts how much they have heaved and we are only about half way through winter. Does anyone know why this has happen? I was thinking it is a combination of the posts not being installed correctly and the standing water in my backyard. I am goint to call the contractor back in the spring and have him come out and repair them.


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## beerdog (Dec 10, 2008)

How much did they heave up? I think the idea is to install them well past the frost line. Is 3 feet code for Canada? What is the code requirements for fence post installations in your area? A common technique is to reverse cone the hole so there is more concrete at the bottom of the hole. This helps prevent heaving.


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## Canadianboy (Feb 2, 2011)

They are up about 1/2inch or so noticeable to the eye. They where suppose to be three feet in the ground. I ambgoing to call the contractor that installed them to come next week and take a look at them. It is really bugging me I wanted to install a patio in that area and now I am worried.


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## Gary in WA (Mar 11, 2009)

Doesn't sound deep enough; http://www.ulteig.com/uploads/Ultei...www.ulteig.com/uploads/Ulteig_Frost_Heave.pdf

http://www.brainerdhomeinspection.com/frosth~1.pdf

http://www.waltersforensic.com/articles/civil_engineering/vol1-no11.htm

Gary


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## jlhaslip (Dec 31, 2009)

What part of Canada? 

It's a big place... if you are in a clay soil, and it is wet,,,,


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## Canadianboy (Feb 2, 2011)

I am in hamilton near toronoto. It is clay soil and the backyard does stay very wet.


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## williamwiens (Nov 13, 2010)

I am in Hamilton as well and have the same problem. ALL of the posts for my fence heaved (some more than others) and it kills me to see lines that aren't level...

The fence was installed by the previous owner so I don't know much about the footings.

However, I built a deck and for the footings used 6 x 6's in sonotubes, 36 inches deep and nothing has moved an inch in 3 years..


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## Canadianboy (Feb 2, 2011)

thanks GBR in WA I was looking all over the internet for information like you gave me. From what you sent it sounds like i have a combination of two problems the posts where not set deep enough i should have had them go at least four feet and i have a drainage issue. I knew I had that issue but I needed to get the fence in because i have a dog and my wife was very pregnant and now we have a little one and she wasn't able to let the dog out. I plan on installing a couple french drains and fix the grade this spring. I really didn't think that this would cause such an issue so quickly. Live and learn I guess I just hope that the contractor is willing to help me out.


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## rditz (Jan 6, 2011)

it is a general rule that the frost line is around 4' deep. your contractor should have known that and recommended that. 

for your deck, I tried a concept on a few that I built and it has worked out VERY well. I go down between 2 1/2 - 3 feet (even hand dug).. through about 6" of gravel, set a deck block in the hole, put my deck post on and fill the rest of the hole with gravel to grade. I have not had a single deck heave... the oldest is close to 10years.

some here might not agree with it,. but it works. the gravel won't let the frost grab the post.

definitely your posts are not down far enough..

rod


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## Gary in WA (Mar 11, 2009)

You're welcome, Cb, and if you do a search in the box above, you would probably find some of my links like these; http://rockproducts.com/mag/rock_aggregates_prevent_frost/

http://www.sustland.umn.edu/implement/deck_footings.html

http://books.google.com/books?id=q3...MyPCQ&sa=X&oi=book_result&ct=result&resnum=10

Gravel under and around the post, as said; http://books.google.com/books?id=1g...=X&oi=book_result&ct=result&resnum=3#PPA31,M1

Gary


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