I have a client who has a home built in 1910. The house has a hip roof that is fairly steep (12 12 pitch), but is flared at the bottom over the roof overhang. The roof over hang is 30″ except at the dormers where there is no roof overhang. At the bottom of the roof flare the roof is almost flat about 6″ and then it starts to curve up slowly to the steep pitch. The house had slate roofing until 10 years ago. Then the slate failed on the lower flater sections and the home owners decided to re-roof. The slate was removed and ashpalt shingles were the choice of the day. Now the lower sections have completely failed to the point that the shingles are breaking apart and on the steeper pitch the shingles are curling. The 3rd floor of the house has an apartment in it that was finished in 1972 using R12 (or less) with paper faced insulation. The roof rafters are about 5″ deep.
All of the contractors that the home owner has called to look at the roof tell her that the roof is failing because the previous re-roof did not use plywood on the roof and that the shingles are junk since they are part of a class action law suit. Now I personally don’t know about the lawsuit, but I think the roof has failed since there is no ventalation in it and the roof design is flawed.
I don’t want my client taken again, so I am trying to help her with the problem. Since I don’t work on roofs anymore I don’t want this job I am looking to help here out. But I would like to see a good solution. I think there is a fundamental problem with the design. The slate roof worked since it allowed lots of air ventilation, but as soon as the ashplat went on it sealed the roof creating no ventilation. To just re-roof is not the answer. Adding plywood won’t make any difference. But how do you get ventilation into this roof? My thoughts were to add 2×4’s to the roof and then add plywood and then re-roof, but ventilation still needs to get into the roof. All of the soffits are closed underneath with tongue and grove boards and then there are aluminum soffits on top of that. What about the dormers? There is no way of getting ventilation into that part of the roof since there is no overhang. And then there is the roof flare. The shingles were not meant for that sort of flat pitch. Money is an issue for the homeowner now widowed and without any sort of large income so tearing off the roof and starting from scratch is not an option as is going back to slate. She needs the best lowest cost solution here.
Has anyone ever dealt with this sort of roof and where do you go with it?
Replies
There are a lot of junk shingles out there. One well-know manufacturer (I'm thinking it was Certainteed) was making crap "25-year" shingles for well over 10 years before the class actions finally forced them to change. And I can see others in this neighborhood that were intalled on new homes less than 10 years ago and are curled so badly they look like they're 80 years old.
I doubt that it has anything to do with the underlayment or poor ventilation (though fixing those won't hurt) -- it's just crummy shingles.
I don't believe that ventilation is the main quetion here.
According to your description, the portion where the shingles are failing is the same portion where the slope is almost flat.
ANY shingle requires at least a 3/12 or 4/12 pitch to function. Asphalt shingles that are as you describe will stay wet for longer and degrade. Tehy are also located at bottom where far more water runs over them ( eroding them) than those midway up the roof.
I would consider a couple possible solutions - One is to re-work that with's hat style to a less tight curve and get some drainage pitch at the bottom. This depends on detailing and how it would change the architectural style of the roof.
The other would be to use a sheet metal ( copper or other) snow shield to run up from the eave 12-24". This is common in New England
I'm not a roofer by trade, but I wouldn't allow a client to re-roof what you have without fixing the flat spot. It's failed twice in the past and it's 100% sure to fail again unless it's fixed. I also would cover the framing with fresh ply as much to match my building style as anything. Old timers that are used to working without ply may do a great job with what's there, but to rebuilt the lower sections and give me a surface for lots of ice and water nothing works for me like plywood and the thicker the better.
Without seeing the framing I don't know if I'd cut new rafter curls to replace what's there, or ply over everything that's there and fix the curl issue over the top of the new ply. The high pitch of the main portion of the roof allows a lot of leeway in the fix so I wouldn't think it would significantly change the roof visually.
Good luck with it!