I want to add a roof extension to my shop. My shop is a stick-built building about 10x20 feet, with a full-height, full-size brick exterior. It has a simple gable roof with brown sheet metal roofing. On one side, the concrete pad extends beyond the footprint of the shop about 10 feet...but it has no cover. I want to cover this area (like a car port) to keep the elements off my small pop-up trailer.
So, I figure I have a few options as far as how to attach the roof extension to the building, but I'm not sure how to support the other end. OK, I figure three or four 4x4 posts with a 10" header spanning the tops of them. But, how do I attach them to the existing concrete?
I've seen the U-shaped brackets that one could use, but I don't know if they are rated for a vertical load. My guess is with a strong wind, the whole thing could be twisted. The posts will be tied together in a few spots (the obvious header, and then probably half-way down the posts will be another tie).
Basically, this is what I want to do: http://www.extremehowto.com/xh/article.asp?article_id=60455
But, I'd rather not have to pour new footings outside the existing slab. Is that the only safe way?