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Discussion Starter · #1 · (Edited)
Received a call from a concerned HO about their deck sinking. This house was an end row home. The deck was built just after the house was constructed about 8 years ago. The house had an addition built on the back, and used the existing stone foundation for the rest of the house. It was a complete tear down and rebuild.

We were able to bring our machine through the 30" security gate and down the alley between the house and the public swimming pool.





The HO had someone come out to try and stop the sinking already. They added more sonotube concrete footings and added concrete to the existing 2 footings. They now have 5 posts on 4 footings.

In total the concrete footings dropped about 2 inches.

Our plan was to cut the patio toward the house of the existing footings, install helical piers, move the beam in about 6 inches and remove the 3 extra posts.



Our machine fit under the deck and we were able to work right off the patio.





As we installed the first post, the ground opened up a little. :eek:

 

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Discussion Starter · #2 ·
More fun

We backed the posts out, called the engineer and came up with a new plan. The downspouts run underground to the street, so they were scoped and we removed some concrete to check if they were leaking. Also had ground penetrating radar performed to check the extent of the void.

Everything came back pretty good. No major drainage issues and the we had already discovered the extent of the voids.

We temp supported the deck, removed the existing concrete footings and installed posts with larger helices. We ended up down about 20' before we hit solid soil. We filled the voids with NS grout and then patched the concrete patio and restored the yard.

The second footing location had a little bit of brick...




The hole opened up pretty good as well.








 

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Very nice. A niche like that will keep you from getting bored.

What is the depth capacity of your machine & size of pier you can drive?
 

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Discussion Starter · #8 ·
Very nice. A niche like that will keep you from getting bored.

What is the depth capacity of your machine & size of pier you can drive?
Depth is based on the soil conditions and helix size. We just keep adding extensions until the machine hits refusal. We can install a post with a compressive bearing of just over 24 kips, with a safety factor of at least 2. So ultimate is around 50,000 lbs. We haven't gone down more than about 27', but some of the other dealers have gone down over 80' for projects.
 

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Basically how we build boat docks. Use Rhino pile driver and big air compressor to drive 2 7/8 drill stem to bedrock.

Nice work, Dan. Will that machine punch those piles through granite?
 

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Depth is based on the soil conditions and helix size. We just keep adding extensions until the machine hits refusal. We can install a post with a compressive bearing of just over 24 kips, with a safety factor of at least 2. So ultimate is around 50,000 lbs. We haven't gone down more than about 27', but some of the other dealers have gone down over 80' for projects.
Holy cow, with that machine? I have limited experience with helical piers on two homes and they couldn't get past 12 feet with a driver mounted to a cat 320. Then again, that was in permafrost :whistling

Pretty slick machine.
 

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Discussion Starter · #11 ·
Holy cow, with that machine? I have limited experience with helical piers on two homes and they couldn't get past 12 feet with a driver mounted to a cat 320. Then again, that was in permafrost :whistling

Pretty slick machine.
The Alaskan dealer is contending with that now. He is performing a ton of projects because of the perma frost.

http://tmpalaska.com/
 

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Dan......

I've only been on two helical screw jobs in my life..... Are you just setting a good footing (pier).... or are you actually Jacking/lifting an existing foundation/footing/stemwall.
 

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Discussion Starter · #13 ·
Dan......

I've only been on two helical screw jobs in my life..... Are you just setting a good footing (pier).... or are you actually Jacking/lifting an existing foundation/footing/stemwall.
On this one we lifted the deck about 1/2" to get it back to level. The concrete sank the first time and the previous guys jacked it up. We did not want to mess with it to much.

We also do foundation stabilization and in some cases will jack it up. We also did a couple house lifting projects on the shore because of Sandy. Those houses went way up...Maybe I will do another thread on those.
 

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So far I've used them for a deck roof and a sunroom addition with attached deck this year. I'm a big fan. I'm going to be considering them for a project that requires strengthening the first floor on a historic home. I really like them.
 

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Discussion Starter · #16 ·
I would have to say that helical piers must be the latest and greatest for construction in sometime . Nice work .
Its been around for over a hundred years... its the installation equipment that finally catching up and being used for some near impossible projects, keeping costs way down.
 

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As with every project, costs are different with different situations. Our prices start WAY lower than that.
I think they all went to 27' depth and maybe a 10" helix (its been many years so I might be wrong) a mini excavator drove them, easy access. Oh we also had to pay a soils engineer to be on site to observe the install, another ~$500.
 
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