Raise garage ceiling by digging?

[plain garage]

We have a 2 car garage on the ground level, ceiling height is limited since one of the bedrooms is directly upstairs. The driveway has a downward slope with about 18" drop in elevation from the garage floor to the street curb.

I wonder if it's ok to dig up the floor and lower it 12" (after re-pouring a 6" slab), of course the driveway will be repaved to accommodate this change. This will give me enough room to make use of a mid-rise lift.

Is this a good idea?

 

[jmlcolorado]

Interesting idea. I don't see why not. I think the biggest issue would be side load on the foundation. Once you remove soils from outside, there's nothing inside pressing back. However, this would be the same as a basement.
I'm going to sub to this one since I think it's a good idea and want to see where it goes.
Way to think outside the box!

 

[southalabama]

Might want to consult an engineer for this project.

Then they are gonna want a soil test and a survey.

 

[GlenC]

There could be a grade beam poured across the opening because of the second story. You might be required to redo the foundation...

 

[alwaysFlOoReD]

I'm not an engineer, however I think going down 18" and then pouring a 6" slab would not weaken the wall enough for collapse. 5 or 6 feet might be different.
It might be an idea to do a test dig to make sure you aren't below footings.

Richard

 

[rancherbill]

Is this a good idea?

Dunno, but it's doable and will be a lot of effort and or cost.

 

[Conductor562]

We dig out railroad tunnels to increase the roof height all the time. I would assume the same principles would apply.

 

[bad_idea]

Build a shop in the back? I am thinking it may cost quite a bit to drop the floor in your attached garage. I would compare that number against building another shop in the back.

 

[seboyandong]

I think the biggest issue would be side load on the foundation.

 

[HoosierMark]

You can do almost anything. The question is will the project provide enough return of enjoyment for the amount of work and cost involved. I doubt if you will generate any increase in the value of your property when you do this. Personally I would not do it. Live with it until you can move to a place that will allow you to have the type of garage you really want.

 

[BRIANBB]

Kick out the resident of the bedroom above the garage and tear out the floor. Cheapest solution.

 

[sands35]

If the floor is separate from the foundation wall sure. Though the wall may not be engineered to support ground pressure on just one side.

Is it a poured foundation or a block wall? Poured you are probably OK - BUT you need to find out the thickness of the wall. If it is the same as a finished basement, then you are probably OK.

If it is block, then you still need to figure out how thick and you may need to install some re-bar and grout. (But I'm not an civil engineer.)

 

[mtmgtz]

Not sure where you are located but removing 12" of soil near the foundation wall (where your garage door is at specifically), you may run into frost heave on your existing foundation since your footing depth effectively was reduced by 12" near where you excavated additional topsoil.

 

[Zeke]

What will the outside grade be in relation to the new slab? Also, how deep is your existing footing? Some 2-story foundations are just wider, not deeper. (IOW, what is your location and weather so this can be intelligently discussed.)

 

[rieferman]

I don't know a lot about lifts, but would it be possible to recess the mid-rise lift into the floor, and not lift the vehicle quite as high? Would that be enough benefit? (I think Jack Olsen did something like this in his shop)

It just seems like a very expensive project to enable vehicle lifting, when perhaps there is an alternative way to accomplish your goal.

 

[Zeke]

I don't know a lot about lifts, but would it be possible to recess the mid-rise lift into the floor, and not lift the vehicle quite as high? Would that be enough benefit? (I think Jack Olsen did something like this in his shop)

It just seems like a very expensive project to enable vehicle lifting, when perhaps there is an alternative way to accomplish your goal.

Yeah, like dig a pit. I know, that is frowned on.

 

[rieferman]

Ha ha, no, I don't mean a pit. I mean, would raising the vehicle up a few inches higher really be that much benefit to incur a huge project? Or, could you recess the lift (so that the top of the lift surface is flush with the existing concrete floor when in the down position) and still achieve a portion of the added height goal.

 

[nolimits76]

Ha ha, no, I don't mean a pit. I mean, would raising the vehicle up a few inches higher really be that much benefit to incur a huge project? Or, could you recess the lift (so that the top of the lift surface is flush with the existing concrete floor when in the down position) and still achieve a portion of the added height goal.

To "recess" a lift is essentially digging a (small) pit for the lift to sit in.

It just becomes a question of how much of a recess does the OP want/need to do. This will largely be determined by current headroom clearance, etc.

But overall, seems like a better solution than redoing the entire floor.

 

[jimindm]

There is a lot of variables in this. The biggest would be how deep is the footings. If the footing are deeper than you want to go that will be fine. It would be no different that how basements were done in the olden years. They built the house and then little by little the basement was dug out, until they got what was wanted. Ever been into an old house that had a three foot wide shelf, at grade level, out to the side of the house.

The next biggest issue would be how the footing made. Block would be great and smooth. A poured foundation would be OK if it was poured with forms. Some like to just fill a trench with concrete, in which case I am not sure how smooth it would be.

Actually thinking about it, its not that bad of an idea. If your footing walls all work out, all I could think of is how to cut the floor near the wall, and getting concrete to the back corners when repouring.

I am not even sure you would need an engineer to figure it out. If you have no posts in the garage, there is no support except at the walls. Having said that, if you are in an area that you will need permits and inspections, its likely that being the first one to try it locally, they may make you do much more.

 

[p_mori7]

We did EXACTLY that at my Dad's house about 10-12 years ago.

No issues to this day.

It was by far the easiest solution so he could park his high roof Savanna in the garage.

Bust out the floor, remove chunks with a skid steer, lower the sand fill in the garage 18", pour new floor, extend door tracks, add a door panel, done.

 

[plain garage]

The house is a split level built in the 1950s, the footer is concrete mixed with rough gravel and about 10" thick at the bottom 24". I have no idea how deep the footer is, but the adjacent half-basement is a good 4' below ground level. The garage floor is actually about 8" above grade compared to ground outside the wall, I guess if I dig 8" there will be no additional side load?

I live in NY, the winters are cold but not frigid for any length of time. I don't think I need to pull a permit for work on the existing garage, but may need one for the driveway. This may or may not happen but I will get some quotes to see if this makes financial sense.

 

[rancherbill]

I don't think I need to pull a permit for work on the existing garage, but may need one for the driveway.

I think you need a permit for this kind of structural work on an attached garage, but, what the heck go for it!

 

[justin1795]

im sure its do able but buy the time a engineer gets involved it wont be practical anymore. multiply your costs x2

 

[Vegaman_Dan]

Doable? Probably. Cost effective? That's a hard call. The costs involved can't be recovered on the house value, so that's really money tossed away for your convenience.

Water table would be a concern.

The angle of driving down and then leveling out to enter the garage might be an issue too, especially with longer vehicles.

If you really need this, then I'd be seriously looking at building a shop on the property for $40-60K if you have the land for it, or selling this house and buying another. It would be money saved.

 

[MN4x4]

You may have inspired me!

I need a few more inches in my shop to give me a better height in my mezzanine/loft. My construction is slab-on-grade - so I can't dig out to gain height - but I *Can* add another bottom plate or two all the way around. One plate would give me another inch and half, two would give me another 3", and so on.

Off to the CAD program to plot my strategy...

 

[GlenC]

You may have inspired me!

I need a few more inches in my shop to give me a better height in my mezzanine/loft. My construction is slab-on-grade - so I can't dig out to gain height - but I *Can* add another bottom plate or two all the way around. One plate would give me another inch and half, two would give me another 3", and so on.

Off to the CAD program to plot my strategy...

If it's detached, why not lift it and add a row of concrete block to raise the foundation ~8"

 

[MN4x4]

If it's detached, why not lift it and add a row of concrete block to raise the foundation ~8"

Ummm...because I can't do concrete myself?

Seriously, I considered that. I haven't rejected it outright, but the concrete would be uninsulated which I also don't like. I think that for me PT wood is the best answer.

 

[GlenC]

Ummm...because I can't do concrete myself?

Seriously, I considered that. I haven't rejected it outright, but the concrete would be uninsulated which I also don't like. I think that for me PT wood is the best answer.

Look into ICFs (insulated concrete forms) .... put them in place like Legos and fill with concrete!

 

[bczygan]

Portable outside lift.

 

[MN4x4]

Look into ICFs (insulated concrete forms) .... put them in place like Legos and fill with concrete!

For you guys that keep suggesting concrete, exactly what is the benefit? I am not against it - I just don't see a benefit?

I can assemble green wood (PT) very easily and slide into place.

•*@#$I can make it any height that I want (within reason)
• It is water and rot resistant.
• It is easy to work using common tools carpentry tools.
• I can build the whole frame in a matter of hours and push it into place myself by hand.
• There is no 'drying time'.
•*@#$I can design it in such a manner as to build in a 'chase' for electrical, Cat 6, and TV/Satellite cable.
•*@#$It's relatively cheap.

What is concrete gonna give me that is better than this?

 

[bad_idea]

Each concrete block gives you 8" while each 2x4 adds 1.5". That would be the benefit of concrete.

 

[oldchevyguy]

I think you will need a permit to dig the garage.Check with your building department for info only.You won't want to do it without a permit,if it's needed,and then need a permit for the driveway.Hard to explain once the job is done.Good luck.