I have crawlspace at the rear of my garage that I wish to turn into a workshop. Currently a small access door is my only entry. I want to add a 3' door into the area. I've only been able to get one of 7 contractors to bid the job. He wanted $3000 to do the job. Seemed a little steep, so wanted to try to do it myself. I've was hoping someone might know of a good book on the subject. Or, is this something I would be better off paying for? Thanks.