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Asphalt shingles for a 1:12 roof pitch?

BayPointArchitect

BayPointArchitect

Sawhorse
Joined
Oct 19, 2009
Messages
516
Location
Lincoln
A roofer called me to report that his competition was finishing up a re-roof project with asphalt shingles.

​The roof slope is only 1:12.

The roofer making the complaint said that he bid that job (and lost to a lower bidder) while thinking that the only suitable materials would include mule hide, EPDM, or high rib steel.

Although no permit/inspection is required for this type of re-roof, I asked the building inspector to stop by the job site and visit with the contractor who was finishing up the project.

The contractor explained that he was using ice and water shield for the entire roof before laying down the shingles.

We enforce the 2012 IRC which states:

Asphalt shingles shall be used only on roof slopes of two units vertical in 12 units horizontal (2:12) or greater. For roof slopes from two units vertical in 12 units horizontal (2:12) up to four units vertical in 12 units horizontal (4:12), double underlayment application is required in accordance with Section R905.2.7.

What I see here is that the extra precaution required for the minimum 2:12 roof slope was applied to a lower 1:12 roof slope.

What would you have done if you encountered this?

Thank you
 
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Our code in Canada is pretty much identical to those requirements. Generally that means they are pretty important. We would generally order that the roof be brought up to code. Whether or not you have a permit out on something is irreverent, if someone brings up a violation and you investigate it, you have some duty of care to ensure it is corrected.
 
The use of ice and water shield is not an acceptable alternative but the work is exempt from permit. I'd say that there's not a lot that you can do about it. If you do decide to push the issue you will be going after the owner and not the contractor.
 
The use of ice and water shield is not an acceptable alternative but the work is exempt from permit.
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I've run into situations where roofs change to lower pitches going over porches and wanted to maintain the shingle/shake/tile roof, but I haven't used Ice & WaterShield, I've hot mopped the roof then applied the shingles/shakes/ or tile over the hot mopping. I would suppose that had the roofer applied 90# mineral cap sheet it would be acceptable. I guess the roofer could maintain that the waterproofing membrane is the Ice and WaterShield and the shingles are merely the protective/architectural covering. There is an old saying: We all live in tar paper shacks, the siding, stucco, shingles, or tile are just impact and UV protection as well as aesthetic.

I'd say that there's not a lot that you can do about it. If you do decide to push the issue you will be going after the owner and not the contractor.
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What's the difference, you do apply the same standards to owners and contractors don't you? BTW, are you proceeding with diversity and sensitivity training in your department? Let's face it, some contractors are minorities, some are gay, others are morons, but all Subject Classes of people you serve have to be treated differently.
 
Lucky for me in NM all Re-Roofs require permits so I would write a corrections to install the proper type of roof cover for the low slope roof.
 
In addition to the water intrusion, the low slope will allow shingle blow off with pretty minor winds.
 
What about all of the nail holes? That voids the warranty for both roofs.
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Tiger:

We put thousands of nails through underlayments every day, yes it bothers me too but it's always done. The worst are tile roofs, we lay the membrane then nail redwood 3' 2x2s horizontally all over the roof, we do gap the 2x2s about 3" at each end, but any water that gets through the tile onto the membrane is trapped until it runs sideways enough to go through the gap to run down a foot to the next redwood batt and the process goes on all the way down to the gutter. The old Spanish tile roofs didn't use batts, but they had a little hole in the top end that they tied a copper wire to which ran up a couple of feet to a small copper nail that was driven through the membrane. It's the membrane that's the waterproofing, the tile/shingle/whatever is just UV and impact protection. In an old tile roof they are good for about 60 years, at that point the membrane is so dried-out that all the tiles are removed, numbered, the membrane is replaced and the tile replaced by the numbers, all with thousands of nails through the membranes. .
 
Ice & Water Shield is intended to protect the wood substrate and prevent water from coming into the structure. Putting Ice & Water Shield over the old shingles will do nothing more than protect the old shingles and waste time and money.
 
conarb said:
I've run into situations where roofs change to lower pitches going over porches and wanted to maintain the shingle/shake/tile roof, but I haven't used Ice & WaterShield, I've hot mopped the roof then applied the shingles/shakes/ or tile over the hot mopping. I would suppose that had the roofer applied 90# mineral cap sheet it would be acceptable. I guess the roofer could maintain that the waterproofing membrane is the Ice and WaterShield and the shingles are merely the protective/architectural covering. There is an old saying: We all live in tar paper shacks, the siding, stucco, shingles, or tile are just impact and UV protection as well as aesthetic.

What's the difference, you do apply the same standards to owners and contractors don't you? BTW, are you proceeding with diversity and sensitivity training in your department? Let's face it, some contractors are minorities, some are gay, others are morons, but all Subject Classes of people you serve have to be treated differently.
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Yes but, contractors are bound by license to follow the code and/or manufacturers warranty instructions, no? Owner my incur liability down the road when attempting to sell and a good home inspector points this out.
 
Obviously Ice & Water Shield must be placed directly on a clean and smooth roof deck or it won't adhere. In this case it would be wise to use Grace's WB (Water-Based) Primer. I've used it and after you put the membrane on the primer its impossible to remove it without separating the poly sheet from the bitumen.
 
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