2 story, partially underground garage planning help??

[Witsbusa]

Hi all. My name is Ben. I have made my way to this forum repeatedly when researching different things, but am finally registering for a project in the early research / planning phase. I am looking to possibly build a detached garage / shop off the end of my driveway for my motorcycles, machines and tools. At the end of the driveway, the yard slopes down to back yard. The drop down is about 9', with the drop occurring over a distance of about 25' or so. If I recall correctly, the width I was looking at was about 32' or so. My mental picture is to carve out the width from the downslope, and have a lower floor for the shop level with the back yard, and then have an upper slab floor level off the end of the driveway. Here are a few pictures of the location:

From driveway looking toward backyard and location where structure would be situated:

A couple pictures from the backyard looking back up toward driveway:

Off to the side from below:

And a couple from beside the driveway and from the side looking toward the house:

I am interested in doing as much of the work as possible as money is an object, and in that regard, it seemed to me that using ICF at least for the lower portion of the structure, if not all the way up to the roof would simplify the process.

I took a look at the "bunker garage" thread a little, but my project is different, so I'm wondering if anyone has any insight into what I'm contemplating, and considerations that need to be factored in as I'm trying to map out the project, and get some firm numbers to see if this is reality, or a financially unfeasible pipe dream..

Thanks a lot in advance for any thoughts and information! I'm looking forward to being a formal member of this board, as opposed to a lurker as I had been for years!

 

[rsanter]

Icf is a good choice as you can set all the forms yourself and then call a pumper truck in for the concrete.
I like the idea but wondering how much if a structured floor you are wanting to do? I thin that will be a big cost factor there. Now if you only want general,storage on the raised floor then you are fine but to hold machines or cars or something would be expensive

Bob

 

[Nephronracing]

rsanter is right on the cost. The last house I built in '02, I contenplated doing a spancrete garage on two (oversized) of the three bays in the garage. If I recall, it was going to be $24K for structure and rough in. I decided against it mainly because for me to get the driveway to go behind the house, I'd have to infringe on wetlands and the DNR would fine me and make me build an equivalent wetland area on the property. There was also the additional cost of the driveway as well. I think the driveway was $0.45 sqft. in asphalt.

 

[readhead]

We have worked on a lot of these garages. Typicaly the concrete walls and framing are brought up to the main level. We come in with steel beams and decking. Concrete is poured for the floor and then framing is finished up.
Depending on the size of the garage it may not be as expensive as you might think.
We recently did a 24'x24' and all the steel installed was around $6,500 and it took about 6 hours to install.

 

[Witsbusa]

We have worked on a lot of these garages. Typicaly the concrete walls and framing are brought up to the main level. We come in with steel beams and decking. Concrete is poured for the floor and then framing is finished up.
Depending on the size of the garage it may not be as expensive as you might think.
We recently did a 24'x24' and all the steel installed was around $6,500 and it took about 6 hours to install.

Thanks a lot for the responses, guys.

Readhead, am I correctly interpreting your post to mean that the steel support beams themselves are $6500?

 

[Witsbusa]

Icf is a good choice as you can set all the forms yourself and then call a pumper truck in for the concrete.
I like the idea but wondering how much if a structured floor you are wanting to do? I thin that will be a big cost factor there. Now if you only want general,storage on the raised floor then you are fine but to hold machines or cars or something would be expensive

Bob

Thanks for the input, Bob. If I am doing it, I want the top level sufficient to pull vehicles in. Motorcycles would absolutely be in there, Handy motorcycle lift, and the ability to hold car / pickups if I am working on something.


Readhead, if you see this, I'm just doing really rough pricing, and was curious what specs for the supports you used for the 24x24?

My rough idea of dimensions is about 25x32, so it's relatively close to what you were working on.

Thanks again for the responses and info!

 

[readhead]

Beams and metal deck.
32' is a big differance. You should have an engineer size everything based on what will be parked on it.

 

[rsanter]

But do you want to pull vehicles all the way in?
Can you use the front part at driveway level for the cars and the back part for storage. You will then have the lower level of the back part as a shop.
How deep do you want it?
If you were going to say 3 car depth you could have parking for cars in the front at driveway level. Then have your drop off to the lower level.
You could install a 4 post lift to use an an elevator and have a service lift to boot.
From the front of the house it will look like a simple single level garage but the back area will be double height. Great for the lift and some tall shelving

Bob

 

[mikefromme]

Depending on what you want to do on the upper level wood framing might be an option. You'll need an engineer to spec the framing for your anticipated loads. But it can be done. Probably end up with 12" on center framing with a max span of of 14-15' or so and doubled 3/4" ply followed by a non combustible floor (tile)

 

[HoosierMark]

A friend of mine uses prestressed concrete beams for his garage and then puts a garage under it. If I understood it correctly, they are they same type as used for building bridges. He and his brother both built houses and garages on hillsides and used this method to have upper and lower garages.

 

[Kevkx125]

Witsbusa I live not that far away. look forward to seeing how your project turns out. A 2 story garage sounds cool, good luck with your project.

 

[LennyTheLizard]

Like this?

http://www.garagejournal.com/forum/s...ad.php?t=83326

 

[onewheat]

Like this?

http://www.garagejournal.com/forum/s...ad.php?t=83326

404 - Link doesn't work

 

[Witsbusa]

Beams and metal deck.
32' is a big differance. You should have an engineer size everything based on what will be parked on it.

Thanks - I appreciate the help with ballpark numbers..

 

[Witsbusa]

But do you want to pull vehicles all the way in?
Can you use the front part at driveway level for the cars and the back part for storage. You will then have the lower level of the back part as a shop.
How deep do you want it?
If you were going to say 3 car depth you could have parking for cars in the front at driveway level. Then have your drop off to the lower level.
You could install a 4 post lift to use an an elevator and have a service lift to boot.
From the front of the house it will look like a simple single level garage but the back area will be double height. Great for the lift and some tall shelving

Bob

In my perfect world, I would like to be able to pull vehicles in.. one of the reasons I'm obsessing about this possibility is I want to take a shot at learning about restoring an old car / truck / jeep.. and with my bikes and other things, there is no way I'm going to fit another project in our garage..

 

[Witsbusa]

Depending on what you want to do on the upper level wood framing might be an option. You'll need an engineer to spec the framing for your anticipated loads. But it can be done. Probably end up with 12" on center framing with a max span of of 14-15' or so and doubled 3/4" ply followed by a non combustible floor (tile)

I've called in my almost brother-in-law who used to run a family construction business, now that I'm trying to crunch serious numbers.. I don't believe he is a degreed / certified or whatever the credentials are, but he knows his stuff..

Thanks for the ideas and input - I'm not opposed to anything, but I want to be sure I'm not regretting going 3/4ths in some day..

 

[Witsbusa]

A friend of mine uses prestressed concrete beams for his garage and then puts a garage under it. If I understood it correctly, they are they same type as used for building bridges. He and his brother both built houses and garages on hillsides and used this method to have upper and lower garages.

do you mean in place of steel I or H beams? I'll add "prestressed concrete beams" to my list to research.. thanks.

 

[Witsbusa]

Witsbusa I live not that far away. look forward to seeing how your project turns out. A 2 story garage sounds cool, good luck with your project.

thanks.. yep, looks like you are right up 422 from me..

 

[Witsbusa]

404 - Link doesn't work

Same result.. curious what he was going to point to..

 

[Riverside]

404 - Link doesn't work

If you click on his signature line, which is the same link, it works.

 

[Witsbusa]

If you click on his signature line, which is the same link, it works.

Thanks for that heads up.. I'll peruse that thread later, but his partial basement got me thinking about cost cutting measures.. I am not going to have significant weight on the lower floor, so I'm wondering if it might save some dough if I went with wood if that is possible for the lower floor as opposed to having a slab down there, and have the upper floor supported by steel posts and beams on footers instead of the ICF up the sides with a full lower floor slab. Or maybe ICF forms for the walls, but wood floor, raised slightly like a shed? Totally brainstorming out loud, so maybe that wouldn't work because of exposure to elements?

I guess no harm in pricing out a few different variations.. fun stuff!

 

[Herb]

I have a garage like this. There is a full basement with overhead door "downstairs", and a driveway down the hill and around to the back for access. The "upstairs" portion of the garage floor starts with an 18" depth I-beam, 4"x 9" hemlock joists 20" o/c, with 3"x 9" hemlock t&g flooring nailed to that. It seems to support my '05 Passat, Tacoma p/u Kubota riding mower and trailer + a lot of junk quite well. I actually like working on this floor more than downstairs on the concrete, and it looks nice, too. Oh, btw, the beam span is 28'.

 

[Witsbusa]

Interesting.. did you need to have a structural engineer sign off on a certain weight capacity to get permit approval? Or was / is it legal to just set it up when you were building?