Old attached garage refresh questions

[ibilisi]

From 20'x20' to 26'x26' attached with deck MN

Hello all, been reading these boards for a while now. I have an old 1930's house with an attached "2-car" garage. Meaning it is ~20x20 (outside dimension) with 2 7'w x6 1/2" h doors.


The current garage has 2x8, 12' OC with a center support beam. Currently the rim is lagged into the house.



The pitch runs high form the house of left to low on the outside garage wall on right when looking at garage. Want to maintain same flow.

I want to expand the garage to 26'x26' (max in minneapolis) and detach the rim closest to the house would detach from the house and be supported by an additional joist. I'm thinking 2 8'w x7'h doors.




I believe a snow load roof in Minneapolis is 40psf, but then you have to consider the deck loads. I believe I am looking at a 100psf requirement.

I have to uncouple the garage because there is a bank of windows on the house constraining the height. These are not egress windows. I want a 6" gap to create a gutter in front of the window and new joists can thus go higher (have to sacrifice somewhere). This would allow normal height vehicles and also prevent me from having a negative pitch driveway. A flat roof with a negative pitch drive would be too much...

I looked at the span tables and a pretty beefy I-joist is required for the 100psf 26' clear span. But I am trying to retain the center support. I am not sure how to size both the support beam in the center and the one offset from the house.

I was thinking I could use these as the joists @ 12" O.C.. The clearspan from the spec at 12" O.C. is 18'-5". Does a center support cut that near in half? From another manufacturers table, a similar sized joist is 100psf live/25psf dead at 12'-8". Menards I-joist

Not sure what would be on ends and center support.
Any thoughts would be helpful here.

 

[ibilisi]

Updated with some "design" information. Hope anyone could chime in with thoughts!

 

[RobSmith]

Need more pics to give any advise....the floor looks like it is lower than the outside level...that needs to be sorted before any further mods are done.

 

[kbs2244]

Call the guy you will be buying the steel from.
Sizing should be a low coast, if not free, service if guaranteed an order.

 

[Krash Kadillak]

I am not a construction expert by any means, but what you are talking about doing seems very involved. Do you have the possibility of an alternate location for a completely new garage? Seems to me that would be more practical. You can use the old garage for a workshop. BTW, is that a deck on top of the garage?

In any case, the modifications you are planning seem so complex that you might want to just tear it down and start from scratch.

 

[ibilisi]

Hey all, thanks for the thoughts. I will have some more pictures up in a bit. But I do agree this is an involved project.

I do plan on tearing down the second stall of the garage, the slab, the deck (gone) and roof. The first stall's foundation is tied into the house's foundation and is in good shape. So the only thing left standing would be that first stall back wall. The rest would be new garage and roof and deck. Sorry if I didn't make that clear.

I have thought long about just putting something on the rear of the property. The problem is the back of our lot is right across from a parkway in Minneapolis. This is why there was a deck and what not. You can have views of the parkway. A garage would obstruct those views. While I'm ok with that, my wife is not....

 

[Daniel Dudley]

Any way to add a bonus space to the back of the current structure ?

What you want to do is totally buildable, sounds like a total tear out and build up though.