Just completed my CPI certification and I’ve been visually inspecting pretty much every house I see. Saw this roof covering on my run the other day and thought it was interesting. It looks cool and seems like it should shed water pretty well, but also kinda looks wrong.
Evening, David. Hope this post hinds you well.
The roof is an English Cotswold cottage roof. The dormer, an English Cotswold cottage eyebrow roof dormer. Cotswold Hills of southwest England.
The main issue is on the sides of the dormer the shingles are not properly oriented. This type of shingle - and most - are designed the shed water perpendicularly with the roof slope. Because there will be water running over the side of the shingle it most certainly is prone to leakage.
I am wondering if the original roof covering was something other than asphalt shingles? Something that would better cover/protect on the outside curves? Thatch? Then that roof was later replaced with asphalt shingles, which is really an inappropriate choice. I would be surprised if this roof was NOT leaking. Even if it is working, thinking the shingles will not last ten years.
(Good) roofers hate things like this but architects design them, contractors build them and someone must put a roof on it. As an inspector, if it’s “performing as intended” and not leaking there’s not much to say. You can point out an “unorthodox” design and mention future repairs are more likely (or however you want to warn the buyer/cover your butt).
Answering my own question. From reading Brian Cawhern’s link, the original “Cotswold Cottage Style Roof Shingles” were heat-treated wood. Heat-treating would allow the wood shingles to be individually warped to their required shape. I would expect that would be quite labor intensive (e.g. expensive) both originally and to re-roof in the same manner. So, when a new roof was needed, the homeowner tried using asphalt shingles.