I want to start by highly recommending aluminum shingle roofing to anyone who wants a good looking 50+ year roof for their tiny house. The Permalock system by the Aluminum Shingle Company is the product I used for my tiny house. I have no professional experience with roofing, but with the installation videos provided and some detailed notes and sketches I created, I found the installation a challenging, but enjoyable, experience.
A word of caution: 45 degree angled roofs are very challenging to work on. If you are working on a steep roof, please use every safety measure to keep yourself and others from being injured.
The first step is to install the drip edge. This is nailed directly to the plywood before the underlayment. Be sure to leave about 6″ extra on either end to serve as tabs when folded around the facia.
I cut to length and adhered the GAF Stormguard underlayment. This stuff can be tricky to work with alone and is very messy. Be sure to wear work clothes and have mineral spirits on hand for clean up. I worked from the bottom to the top on each roof slope and capped it off with smaller and more manageable pieces at the ridge caps. Each layer overlaps the last by at least 6″.
Once the underlayment is in place then a frame of various aluminum sections are trimmed, shaped and nailed in place to form a start and end point for the shingles on each roof section.
The shingles follow a very basic pattern that is then modified for special features. The rhythm is simple to maintain as long as you pay attention to the half mark on each shingle. This will make sure they continue to line up on each course.
Finally, the shingles are finished off at the top of the roof with interlocking ridge caps.