# adding a 2nd story to an existing garage



## chrissygarden (Aug 18, 2009)

I have a 
2 car garage on a floating slab
2x4 construction
the roof / trusses is a gable roof... not real steep.. 
the garage is a standard looking garage that you see all over

My question is, can I make this a 2 story so I can have storage or living quarters on the top level..

2nd question is can I make this 2x4 contruction into a 2x6 contruction?

and where can I get some information and plans on how to do it?

Thanks.. I am a novice carpenter!


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## Scuba_Dave (Jan 16, 2009)

Can it be done - Yes
Are you planning on doing it?
You will not find exact plans/instructions, you would need to either draw them up yourself or hire someone

Is it 1 garage door - big, or two?
Why do you want to change the 2x4 garage into 2x6?
Or do you want to just have 2x6 on the 2nd floor - more insulation?

Rip the roof off
Put a new floor across
Build new walls
Build roof
Finish as needed


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## chrissygarden (Aug 18, 2009)

There is 2 garage doors...

I wanted it 2x6 construction to add insulation and I thought I may need more support for the 2nd level..

I live in Wisconsin, so I was not sure if the floating slab could take all the weight of the 2 story addition.

And can I raise the height of the walls on the first story? 

Thanks for your advice...


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## Scuba_Dave (Jan 16, 2009)

So there isn't a foundation under the garge walls?
That will be a problem


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## chrissygarden (Aug 18, 2009)

*no foundation*

just a floating slab...

but it is in real nice shape, the concrete is about 5-6 inches think..
So what do you think>>


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## Scuba_Dave (Jan 16, 2009)

If its just a slab 5-6" thick I doubt it will carry the weight of a 2nd floor
Is this attached to the house?

My (new) attached garage w/2nd floor & walk up attic I had to put a footer & foundation in down to ~4'


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## chrissygarden (Aug 18, 2009)

*the garage is free standing...*

So do I have any other options to get this garage a 2 story besides tearing it down and starting over with a concrete footings???


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## Scuba_Dave (Jan 16, 2009)

That option would be beyond me - you need someone in concrete
Possible you could dig out & have concrete poured under edge of slab
Or jack up garage, cut edges of sab & have foundation poured
But beyond my experience


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## Gary in WA (Mar 11, 2009)

I suggest you contact your local Building Department, and ask them.

The minimum code accepted is 8" wide concrete wall on a 12" wide x 7" deep concrete footing to support a two story building. 
You may get by with an engineered footing down at your frost depth, pinned and poured under the slab, but again, it's a local thing. 
Ask them if they accept this, a lot easier: 
http://www.oikos.com/esb/43/foundations.html

Be safe, G


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