Building a shop / shed / barn / greenhouse

[PandDLong]

Grade beam trench is carved out and screw piles around the perimeter were started.

They are 10' and none of them torqued out so they were left at 9' deep and extensions will added to each one. In a test of a couple piles a week or so ago, one had torqued out but it must have been a very localized spot.

While extensions add $$ it confirms that all of the other ideas about using ground-contact posts - eg. posts set deeper in the ground, concrete pads for the post to sit on at the bottom of the hole, uplift wings bolted onto the posts - would not have worked. Not only is there a high water table and the posts would be wet with potential frost problems, the soil doesn't have enough bearing capacity to hold the posts properly.

Skipping the multi-thousand $$ geo-tec study and going straight to screw-piles was the right idea. (hopefully it didn't exhausted my pool of right ideas ....)

 

[EddieWalker]

Posts ever 6 feet is a lot better then posts farther apart. Most people don't put them in so close to each other because it's a lot more work, and money. But with them at 6 feet, you will have a lot more strength, and hopefully, they will stay in the ground a lot better then the previous building.

 

[PandDLong]

Screw pile extensions were added on a rainy day - they all used between 5' and 10' of extension before torquing out.

Leaving an interesting array of pipes in the ground.

Now they are all cut and capped.

 

[PandDLong]

Grade beam forms being built - will get this poured after the Canadian Thanksgiving long weekend (which is this coming up weekend).

 

[shooterdon]

Never heard of screw piles and found this interesting and informative.

You seem to be doing a very good build and hope it works out for you.

 

[deezler]

Nice, looking forward to seeing your pad poured.

Do you have a before pic of the screw piles? I picture them a lot like a post hole auger, sorta? And then you screw them into the earth until a pre-set torque is reached, which indicates proper foundational strength? Is the torque setting adjustable? As in, do you ever worry if the excavator operator has it set right?

How do you tie the cut/capped screw piles into the concrete foundation or post brackets?

 

[civilian]

Did I see on your floor plan, a 10ft wide 8ft high overhead door? Depending on your equipment, a tractor on your trailer may not fit in the door. All my doors are 10ft high. B26TLB fits on the equipment trailer under the doors.

Interested in all these builds. Jon

 

[PistolPete]

Great project. The helical piles are a great idea for dealing with your soil issues

 

[PandDLong]

Nice, looking forward to seeing your pad poured.

Do you have a before pic of the screw piles? I picture them a lot like a post hole auger, sorta? And then you screw them into the earth until a pre-set torque is reached, which indicates proper foundational strength? Is the torque setting adjustable? As in, do you ever worry if the excavator operator has it set right?

How do you tie the cut/capped screw piles into the concrete foundation or post brackets?

They are a lot like a post hole auger - but the helical coil only wraps around the bottom about a turn and a half (which was a surprise for me, I was expecting many more "turns"). There's a pic below of some before use (and some 5' and 10' extensions).

I suspect there are different types of units to drive them down. My contractor has a locally made unit which attaches to his auger head and measures the torque as it is turning - that measurement is sent to an app on his phone (effectively a wireless digital gauge). He stops when it passes his torque target (and if it close to being all the way in, i noticed he keeps going to save the need to cut the pipe). He takes a screen shot of his app and gives me a record of the torque each screw pile hit.

He calculates the target based upon the needed load bearing (with a generous over-estimate) and the diameter of the screw pile (all of mine are 2 7/8" or 2 3/8"). The smaller ones are used where the load will be relatively light (eg the greenhouse and open lean-to's). I have to trust that the training for his certification and his math is right.

He cuts the pipe with a cordless band saw. If the pile is going to directly support a post, he welds the cap to the pipe and then we'll bolt a saddle onto the cap. The ones around the perimeter will have the concrete of the grade beam settle around the top of the pipe and the cap so the cap is effectively inside the bottom of the grade beam. For the building lumber posts, saddles will be wet set into the grade beam.

 

[PandDLong]

Did I see on your floor plan, a 10ft wide 8ft high overhead door? Depending on your equipment, a tractor on your trailer may not fit in the door. All my doors are 10ft high. B26TLB fits on the equipment trailer under the doors.

Interested in all these builds. Jon

I debated that door height - my old shed had full height 12' sliding doors which would fit practically anything. I dropped the height of this new build down to 10' as I was never using that extra height and it was a bit of a cost saving measure (and the shed seemed to loom over my yard so I am hoping it blends in a bit better being shorter).

Then I wanted a overhead door with a remote because I found I frequently left the tractor out because I didn't feel like getting off and manually opening/closing the doors - I would tell myself "I'm going to use it tomorrow/next couple of days/on the weekend, I'll just leave it out". So I am compensating for my laziness by having a powered door and a remote on the tractor. Given a 10' interior height, that really just leaves an option for an 8' door.

The garage on my house is an 8' door and the tractor fits - but with only an inch to spare. I never put it on a trailer (unless it is broken) so that is not an issue.

I may regret my 8' door in the future when I acquire some other piece of equipment or trade-in my tractor and everything is 8' 1" - but I sure hope not.

Michael