Digging Out under garage Crawl Space to increase Tractor Storage

[ultrarunner]

I have a 22 x 30 elevated concrete slab garage on a down slope.

Access under the garage is by a double door set into an opening 8' wide x 7' tall.

The open area is barely big enough for my BX... removing dirt with the BX and underpinning the foundation would give me at least 4 times the usable space.

The easiest way to shore up would be using a bench underpinning... this also would take up lots of room.

The other way would be excavate alternate sections along the foundation, form and fill with concrete...

The current foundation is basically a on grade inverted T concrete.

The garage is separate from the home and is stand alone... the cripple walls supporting the perimeter are 2 x 4 and there are four would posts running down the center under a wood beam.

Any ideas from the TBN brain trust?

 

[bcp]

An additional building might be easier.

Bruce

 

[turnkey4099]

I wouldn't dtackle it. It sounds like a professional, engineered job. Not something a DIYer drew on the back of an envelope.

Harry K

 

[ultrarunner]

An additional building might be easier.

Bruce

I've been unsuccessful in getting approval for my barn... no accessory buildings allowed... the garage was built 35 years ago prior to all the new restrictions...

 

[radioman]

Instead of digging, can you raise the building? It probably won't work if it a pole style of bldg. If it a standard stick 16 OC, I dont see why not?

 

[CurlyDave]

I did this with my house ~ 25 years ago, using nothing but hand labor.

It can be done, but will require an engineer to produce stamped & signed drawings.

Supporting the slab will be the hardest part, even a very small deflection will crack it.

Personally, I would work the dirt by hand, using the BX only as a motorized wheelbarrow to carry the spoils out. Knock over a support with the BX and you are in a world of hurt.

Get something like a Makita 1304B electric demolition hammer with a clay spade to loosen the dirt (think of it as a very strong pick, which can be placed exactly where you want, before you pull the trigger) and scoop the loosened dirt into the bucket of your BX for carry out and dumping.

You will need to pour new footers to support the existing garage before you do much else. Go over all the construction steps with the engineer before he finishes his plans, he may design a structure where the finished product is good, but there is no way to get from where you are to finished.

See what it would take to do away with the center supports, but don't be surprised if that is very difficult.

Pay a lot of attention to drainage, and go as deep as you reasonably can. You do not want to do this twice because you didn't go an extra 6" deep.

 

[magicheater]

A picture would speak volumes.

 

[KennyG]

This sounds to me like a very difficult job with only marginally acceptable results. Have you thought about just tearing it down and building what you want. I know the cost would be significant, but the value added to your property would be considerable.

 

[ultrarunner]

The freestanding garage with basement already exists...

I was hoping to gain some additional depth to accommodate more than just the BX

Wasn't really thinking of making the entire area open... would be nice in an ideal world.

So basically, what I'm looking at is modifying about 20' of one 30' side.

The door height, rear exterior elevation and leaving most of the foundation undisturbed dictate inside height of 7'2"... for the bay.

One design build company took a look a few years ago and suggested building an I beam frame with piers... basically the new structure would support everything...

I remember you mentioned a similar project Dave...

What did you start with and what did you end up with?

 

[Taylortractornut]

I have a friend that had a conventional frame house like the one I live in now. He dug down under his house with a 2cycle Stihl tiller losening the soil. WHere his block peire were he made temporary supports on either side of the beam and would go down 2 block heights then ad the blocks and pull the 2 temps and dig out there. His house was on a hillside and when he got below the block footers he slid in an Ibeam unther the old footer. I came in the the mini ex and dug down a ram. As I dug he put in cribbing under the beams.

Then he dug out with his tiller and a650 HD tractor.