Racking is an application technique where shingles or tiles are installed straight up the roof deck in vertical columns. While this limits the distance an installer has to move across the roof, it requires lifting the edge of already-nailed shingles to tuck the next course underneath. Bending shingles this way can crack the fiberglass matting, especially in cold weather, and often voids manufacturer wind warranties.
You can see where they were racking the field shingles because every fourth course has a torn edge from being forced under the nail.
Racking forces the installer to blind-nail the final fastener under a seated shingle, which often leads to under-driven nails and future blow-offs.
Also heard as
- straight up application
Related terms
Shingle lap
Overlapping layers so each upper piece lies over the one below, sending water down and out like roof shingles.
Fishmouth
An open wrinkle at the edge of a membrane lap that forms a channel water can run into.
Reverse lap
A lap installed the wrong way, with the lower layer over the upper, so water is channeled behind it.