I appreciate you showing these layout concepts. One of the toughest things for me is figuring out how to deal with the fact that roofs are out of square, and doing a layout where you don't end up with a tiny cut shingle at the end of a course, regardless of what pattern. One of your other videos shows how to even out shingle courses from top to bottom so you don't end up with a "vanishing" row at the ridge, etc. Most RU-vid videos don't show how to deal with a crooked roof.
Straight and square roofs are hard to come by. When you are dealing with 10's of feet from one side to the other, spaces and not spaces between material can add up. It is better to lay out the section and hide the imperfections in the middle. Square doesn't necessarily mean better built, unless it is way out. There is always a variance and an allowance in construction. Being able to deal with it gets the job done.
Shingle manufacturers will throw their manufacturers warranty out the window if you rack shingles like this. It makes the shingles more susceptible to wind damage
I don't doubt that there may be some manufacturers that frown upon it, but the exact words of the last of 3 methods in the Certainteed 3-tab installation instructions is - The alternate “Six-Inch, Single-Column, Vertical Racking Method.” www.certainteed.com/resources/CT20Intall.pdf - page 93 - right hand column - towards top. I believe that the reason it may not be recommended for wind resistance is that installers (or non-installers) will be more inclined to "3-nail" if they rack them. If this is the case, then the absolute minumum of 4 nails would only be in a few shingles and most would only have 3 nails. Around here we put 6 nails in each shingle minimum (as seen in this video or the next when I actually install the shingles). I know in the laminated shingle installation instructions (probably most manufacturers), it is stated very clearly "do not rack". I believe it is more about seeing (or not seeing) the side-lap than wind resistance. Thank you.
