Shingling the valley
I have now started shingling the other back roof on the Fairfield, which includes a 'valley' where the back roof meets up with the side roof. I learned when shingling my Willowcrest that you can't just draw lines the same distance apart on two roofs that meet at a valley. If one roof is at a different angle, then the shingles just won't line up visually. I found the best way to do it was to designate one roof to be the 'main roof' on which you draw the spacing lines (this is probably the roof with the bigger area), and then line up the tips of the shingles on the second 'minor' roof to visually continue the shingle line. You can see what I mean on this picture of my Willowcrest dormer. The shingles on the dormer are longer, with more shingle exposed, because the dormer roof is at a steeper angle than the main mansard roof. Yet the shingle tips are lining up visually. I also found that for a neat result, I needed to shingle one row at a time on both roofs simultaneously. I couldn't do one roof, then go back and do the other roof.
1) So on the Fairfield, I have drawn the first line 3/4 of an inch up from the edge of the side roof, then further lines 1/2 an inch apart. This is my 'main roof'. In this pic I have shingled up to where the valley starts, and completed the first row of the main roof where it meets the valley. I fill in with cut shingles snugly into the valley 'crease'.
2) Then I start the first row of the valley, again butting a cut shingle snugly into the 'crease' of the valley.
3) Then I do the second row of the 'main' roof. This time I am going to butt a ruler up against the tips of my second line of shingles, and mark a continuation of this line onto the secondary roof.
4) Then I place the second row of the secondary roof, aligning the tip of the shingle with the line I drew in Step 3. Again, I cut part shingles to fill the gap in snugly to the valley. As the cut pieces aren't overlapping another shingle, they will lie slightly flatter, but don't worry about this as it will mostly be hidden by subsequent rows.
5) The third row is just a repeat of Steps 3 and 4. On the secondary roof, I am now starting to stagger my shingle tips so that the tips line up with the seam in the row below.
Now, the tricky part of this process is that when I reach the top of the master bedroom cut-out, my row of shingles on the secondary roof will need to extend across the top of the master bedroom cut-out to reach the edge of the secondary roof. It will need to do so in a logical pattern continuation of the rows of shingles coming up the right side of the master bedroom cut-out. As this right side of the secondary roof starts at a lower point than the valley side on the left, I am going to need to do some fudging to ensure that my shingle rows will line up. I am going to do a few more rows like Step 5 until I have enough of a pattern that I can extend the lines across the cut-out space to the right hand roof, using my quilting ruler. Then I can draw lines lower down on the right-hand side, adding or subtracting smidgens from my usual half-inch separation, to make the shingle rows work out visually on the right hand side. And I bet all that is clear as mud... :)