Adding on to my garage

[sharpshooter]

I going to be adding on to my existing garage in the back. Unfortunatly not real big but probably a 12x12. I will be building off the back wall of my garage. The grade behind the garage is about 2 ft lower than the foundation of my slab so I planned on just coming of that back wall with a lean to style roof, that will still leave me a good 8 ft ceiling at least. Anyways I was curious as to how to tie this roof in to the existing wall. I thought about just screwing a 2x4 or 2x6 to it and coming off with 2x4 rafters, Would that be the best way? Ill probably just use metal roofing (that way I dont have to use plywood on the roof) This addition will just be holding all my lawn and garden stuff and possibly my air compressor. I will put up some shelving to hold any other stuff but its mainly just a storage room.

 

[Bambam]

That is basically what we did with ours. The garage is 20X40 and just had a shed type door opening with a small back room big enough for the refrigerator. You can kind of see the outline from the old room in the picture. We put a 2X8 or 10 (can't remember) across the outside wall of the garage to attach the 2X6 rafters to. We used lagbolts to attach it to the existing wall and then after putting on the plywood and felt paper on ran some aluminum flashing the full length of it to seal it up because we opened up the old doorway to make a bigger entry into and out of the garage/addition. Now we have an 8X16 room on the back for workbench, toolbox, etc.

 

[Torque1st]

12' seems like a long ways for a 2x4 rafter.

For your rafter size go here:
http://www.southernpine.com/spantables.shtml

Some municipalities in your area may list the snow load requirements for a roof. The minimum specs may not always be the best. It is usually advisable to go at least one size heavier. For the ledger board on the wall go at least one size larger than the rafters chosen.

Build it right the first time. It is very expensive to build it twice after it collapses.