Hit water while digging pole footings
drptop70ss
| Posted in Construction Techniques on
Just started digging holes for a pole barn, 40×60. I am digging 4′ down, and was going to use 12″ sonotubes filled with 1′ of cement and then set the 6×6 PT poles in the sonotubes and backfill with cement. Problem is after digging a 4′ hole in the ground, the bottom 1′ is filling up with water from the ground. Fills up in about 30 minutes! What can I do? This is the only location I can put the barn. What are my options? Can I still continue and maybe pump out the water while putting in the cement footings? Should I put in 2′ of cement in the bottom of the tubes instead of the planned 1′? Any ideas would be appreciated, I really want to get a shop up.
Dave
Replies
What we used to do in this case was to dig down far enough to get a good base and fill w/ crushed stone. Then pour the footing, then set the column, then backfill w/ crushed stone.
Don't surround your columns with concrete, it will accelerate the rotting process.
What's your frost depth? You may have to add fill to get your footings deep enough.
Frost depth here is 42" for code, but I have never seen frost here deeper than a couple feet. How do you know when you have dug deep enough for a good base? Do you then add the crushed stone until you are above the water line and pack it down? I have been thinking about what to do, what if I dug the hole and put in 55 gallon drums as sonotubes, then backfill around the drum before the water sets in? I would leave the drum bottoms in so the water couldnt get inside, then fill the drum with cement after the poles are set. Also I have to backfill around the poles with cement, the building inspector insists on it here.
Droptop,
You don't want your post underground w/ or w/o water. Use the sonotube and fill completely w/ concrete. (Not to be a smart a** but if you have cement you have a problem.) Use a stiff mix and it will displace the water. Concrete will set up under water (like the Hoover Dam). Place some sort of steel connector in the concrete for your framing like a Simpson product and build from there.
Is it a Malibu?
Gotta have the poles in the ground for shear load. The bld inspector wont allow them to be set on top of sonotubes for a pole building, although I have seen buildings done like this in other areas. I want to do this right, but I havent talked to the inspector yet as I am afraid he will tell me I cant build with the water problem. There must be a way to fix this, I am leaning towards putting tamped gravel in the hole and then using the 55 gallon drum as a sonotube. Anyone have experience with something like this? At least if I know the correct way to do it I can deal with the inspector.
Dave
Jalden, the drptop is a 70 chevelle SS396 convertible.
The connector per the previous post takes the shear load, and can be such it even takes bending moment. If your building inspector wants the posts in the ground, he's got some gears loose somewhere, or is a big PT fan and stockholder.
Edited 5/11/2002 12:10:10 AM ET by JUNKHOUND
I agree, this inspector is a loose canon.
It would be idiotic to surrond the post with concrete.
Excellence is its own reward!
I agree that putting the poles in the ground with concrete isnt the best way to go, but I have to use .60 CCA posts so I would think they would last longer than I will. Does the crushed stone and then the drum sonotube sound like a safe way to go? I just dont want to have the building sink any years from now.
My choice would be stone base and a concrete base with mechanical attachment to the post. You can also pour into water, it'll just float out as you pour the mix into the form.
Sinking the post partially into the concrete will anchor the post by friction instead of mechanically but will invite not only rot but allow water penetration to the joint which does several things. It will freeze and expand, possibly enough to crack the concrete unless rebar cage/collar is included within the form (I donb't care whether the form is a barrel, wood, sonotube or whatever) This craking can extend vertically down into the lower portion (footer) of your pod, separating it and unbalancing the load distribution it is intended to carry. Alternatively the frost could be under the post in its pocket and lift it up and away from the concrete pod base. Drilling a rod through it, below the top of the pour could help with that.
Pocketing water around the base of the post can also cause it to swell, putting pressure against the concrete with the same results mentioned above and adding the weakening of wood fibres from the crushing effects. Probably not enough to worry about but still avoidable. A mechanical fastening plate set in concrete avoids so many of these problems at less cost.
Excellence is its own reward!
I've dug plenty of footer holes that were below the water table and never had an inspector reject them (as long as they were deep enough).
As it's been indicated concrete will cure under water, personally I would pour a footer of concrete set the 4 x 6, back fill and forget the Sonotube.
Scott R.
I've dug plenty of footer holes that ended below the water table and never had an inspector reject them, (as long as they were deep enough).
As it's been indicated concrete will cure under water, personally I would pour a footer, set the 4 x 6, back fill and forget the Sonotube.
Scott R.
Thanks for all the info and opinions, I really appreciate it. I have a load of stone coming today, I will make sure I am down 4', fill stone for 1', and then set in a drum which is 3' tall. I am on solid ground, lots of shale and clay actually which is why the water doesnt drain away quickly. I will ask if I can fill the drum to the top with cement and then use a mechanical anchor, but if he wont let me do that I will fill the bottom of the drum with 1' of cement and put in 1/2" rebar rods that will stick up into the upper half of the barrel which will be filled with cement after the posts are set on the cured first 1' of cement. Will that be enough support? Do I really have to worry about the .60 posts rotting?
with 60pt not rot so much as other things I mentioned but that's life. Sleep well (after letting the air out of the inspectors tires)
Who said that?
Well, good to know that both scotts agreed with us.
LOL
Excellence is its own reward!
Has the thought occured to you that you might have an artesian well.? An endless spring ?????? Which either might be worth more in the future than the building. You might have been blessed.
Tim Mooney