What issues with attaching a detached garage?

[Bad00SS]

I have a building 6 feet away from my attached 2 car. I wanted to connect the gap so I had some concrete poured the other day between them. it just has a normal gravel base that was compacted and a 4" slab. The neighbor came over right after and was telling me its not going to work because the detached didn't have a foundation as solid as the house does and one will sink or raise and it will rip the boards apart or crack all the drywall in that connected room. says its a nightmare waiting to happen. I think he's crazy. I've seen people do this. Its a garage so if the drywall cracks oh well. I cant forsee it sinking or raising more than an inch. Not like the roof is going to collapse or something. What's your guys experience on this?

 

[NUTTSGT]

It's possible you may have issues with heaving during the winter. I have a section of sidewalk that heaves every winter by the walk in door to the house garage.

Are you just doing a roof over a sidewalk or enclosing a space like a breezeway ?

 

[Bad00SS]

enclosed and there will be a doorway cut in the wall on the attached so it can all be connected. then the new area will get heat from the existing heated garage along with the detached part.

 

[Stuart in MN]

I can't say if it will rip the boards apart, but in standard construction techniques the garage should have the same type of foundation as the house, so they don't move independently of each other as a result of the ground freezing and thawing.

 

[NUTTSGT]

I can't say if it will rip the boards apart, but in standard construction techniques the garage should have the same type of foundation as the house, so they don't move independently of each other as a result of the ground freezing and thawing.

This is what I was thinking but wasn't sure of what you were building. The heat you mention may be enough to prevent issues but don't be surprised if you get some movement during the winter.

 

[toolmiser]

I have the opposite. My garage was built on a slab detached from the house. Previous owner built an enclosed breezeway between the two. I decided to enlarge the garage by adding a stall. City required I have a foundation to go below frost (WI). So I knew I would not win that battle so I have full foundation on three sides. It's been up 20 years and I've never had a problem. Wouldn't recommend going this route, but I didn't have much choice.

 

[klassenl]

This sounds like a fun project.
To clarify: you want this to be a full living space.
I don't know how the differences between the buildings (all 3 of them) will play out. I would be tempted to leave the breeze way insulated but unheated. For 2 reasons 1) you won't have as much difference in temperature 2) You may get around certain rules by calling it a breezeway and not a house.

 

[Bad00SS]

its all garage so I don't think that matters. its just gonna be a 70 ft long garage if I knock that wall out. it already has a house furnace in the attached part just for the 2.5 car area.

 

[kbs2244]

I doubt the code will allow it without a full foundation under the now "attached" garage.

 

[Bad00SS]

how can they prove what the foundation looks like on a structure built years ago? I cant even verify if it has the correct foundation or not without digging way down next to the slab. I'm honestly too lazy to try and dig a massive hole 3-4 feet deep to see how far the concrete goes. I was just gonna connect it and hope for the best. Now the small 6ft wide portion I just poured is only 4" thick which I know, but no one else knows without digging.

 

[billie]

You should need a permit and drawings. There are issues of fire separation which are far more critical than the foundation. But yes, you may have to dig down to verify the existing foundation OR your municipality may have plans from the original construction permit.

There are valid reasons to file a building permit.

 

[ericlar80]

how can they prove what the foundation looks like on a structure built years ago? I cant even verify if it has the correct foundation or not without digging way down next to the slab. I'm honestly too lazy to try and dig a massive hole 3-4 feet deep to see how far the concrete goes. I was just gonna connect it and hope for the best. Now the small 6ft wide portion I just poured is only 4" thick which I know, but no one else knows without digging.

They will just have you dig way down next to the slab to see what foundation was used. Happens all the time...

 

[Bad00SS]

I'm going to have to do some research on whats going on with the existing garage concrete vs the newer detached concrete and maybe all it will take is a 6ft wide footing in front and back where I poured that new concrete connecting them and it will all be up to code. Its more work but not horrible if both garages currently meet code. just short sections of the correct footing to be added.

 

[kbs2244]

They may let you get by with just a roof.
Then canvas, in the winter, will provide a walkable path.