Job Example of Asphalt Shingle Installation
What We Do
Often on low slope roofs, roofs with a pitch less than 4:12 (18 degrees) we cannot install slate shingles because they will leak and it doesn’t meet building codes. One solution for a low sloped pitch is to install asphalt shingles which can go on a pith as low as a 2:12 (10 degrees).
On this job the roof sweeps from a steep slope 12:12 pitch down to a low slope 2:12 pitch. This caused major leaking which rotted out the decking boards. To fix this we started by removing the slate and fixing the decking boards.
After replacing the 1x6 decking boards we adhered ice and water shield to the decking as a added precaution against ice creep and sideways rains. Once the ice and water is in place we will then installed install asphalt shingles that mimic the look of slate so that the roof has a cohesive appearance.
One area that is very important to address is the transition where the slate overlaps the asphalt shingles. Asphalt shingles and slate shingles are a different width and also lay down at a different angle. Therefore, we install a wooden cant strip which is the thickness of a piece of slate (1/4” thick) so that the slate is installed at the right angle of the roof. This provides tension on the first course of slate keeping them from breaking. If the cant strip is not installed the first few courses of slate will break because of the uneven tension.
Lastly, we install slates in place using slate hooks or metal bibs. This way there are no nails going through the slate that allow water to penetrate the roof.