Replies

1. 
   BillHartmann | May 20, 2005 12:53am | #1

   The problem is that the footings only go down to frost dept, which can be from a few inches to about 4 ft or so, depending on where you live.

   And if this is a detached garage then it might not even be below frost depth.

   If it is detached then moving the garage and rebuilding the foundation might be a better idea.

   "eplace with concrete slab and metal trusses for support"

   Properly designed there is no need for trusses after the concrete has cured. I have space under my garage is had temporary supports with plywood and trusses when it was poured. Just takes a little more rebar.

   But if I was doing it today I would use ICF system. They also need have temporary support, but they give you insulation, paths to run utilities and easy connections to finish the ceiling.

1. 
   lampe3d | May 20, 2005 01:04am | #2

   The garage is attached. The rest of the house has a fully finished basement. We were hoping that we wouldn't need to rebuild the garage or part of the house to do this project but perhaps we are dreaming. We have an architect coming on Tuesday but thought that the collective wisdom of this forum may bring up issues that the HOs(us) and the architect may not think of.

1. 
   timothale | May 20, 2005 04:08am | #3

   I've seen a few where they use what the Iron workers call pan decking.  It's used in commercial buildings, skyscrapers etc.. various sizes of metal corigated  sub floor . the height of the wiggle and thickness depends on the span. usually temporary bracing is required underneath until the concrete cures.  I've seen jobs where they dig out the center and leave the outsice footings in place then pour new footings at a greater depth inside the existing  footprint. A soils engineer usually has to approve soil type and compaction so it won't cave in when you are digging. 

2. 
   Piffin | May 20, 2005 01:38pm | #4

   In the long run, it's going to be cheaper and better to tear the garage down and start fresh to get packed in under like that.

    

    

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1. 
   lampe3d | May 31, 2005 05:14pm | #5

   Update: We had an architect come out. The architect said that it would be cost prohibitive and maybe a bit dangerous. We would have to put in precast concrete that is reinforced with steel beams. We live in an area that has a large amount of salt and the architect felt that, overtime, the exposure to salt would weaken the steel beams. We have abandoned that idea and are now thinking of an addition.

1. 
   Woodbutcher | May 31, 2005 09:40pm | #6

   In that case.   Instead of going down under the garage for your extra space,  what about going up?  would adding a second floor above the garage ruin the architectural appeal of the house?    If not, I think that it would be much easier, cheaper, and give you more options for how to use the new space.