Building a garage addition

[lzicc]

I have a few questions on adding on to my existing concrete block garage.

The current garage is 19' x 40' x 8' tall. I am going to add onto the left side of it which is the 40' side. I am going to be using 8" concrete block to build the walls and the addition size will be 25' x 40' x 8' tall. My question is, what size footer should I put in for the block. I'm in western Pa, so I will pour the footer 36" at the frost line. I have been looking on the internet and I get different answers. I was thinking about going about 16" wide at most and about 8" deep. My concern is the depth. I don't want to pour it too thick with the cost of concrete. I am also debating on just going up 6 courses of block and go the rest of the way with wood.

Also, where the new footer meets up with the other garage footer, I was going to drill holes into the old footer and epoxy some re-bar to tie it into the new footer. Is that necessary?

The base I am pouring the footer on is solid. It's all shale which would be a good, solid base. That brings me to my other question. There is no way I will be able to form the footer using wooden stakes, I'll never be able to drive them in. What else could I use for stakes besides wood? I was going to use rods, but what would be the best way to secure the forms to them?

 

[fbiwrench]

I am not a expert on the subject so take for what it is worth, but I did see a article in a magazine where they were building a home in the mountains. The soil was almost 80% rock and they used insulated concrete forms, ICFs, and partially filled in and around them with stone or gravel to hold them in place. They also hold the rebar in position and when you are done pouring concrete you leave them. I thought it was good approach to it and they set up fast.