Roof shingle ?

[Halfathumb]

Here is part of the study guide I used for licensing. A lot of real good information in it.

I was called to be an expert witness for an insurance company who was being sued by the home owner because the insurance company denied a hail damage claim. The claim was fraudulent and I used this document to back me up. The insurance company won. It was an old roof that needed replacing so the home owner went on the roof with a ball peen hammer and damaged his own roof.

I can tell you what a home inspector looks for:

Any exposed fiberglass on the edges of the shingles, cracks, deformation and granular loss. You can see the granules in the rain gutters and on the ground at the downspouts. The granules act as a heat sink and help cool the shingles and help reflect sunlight. When they're coming off, your shingle looses it's protection from sunlight and heat, including heat from the attic. So we like to see uniform granule cover. If I can see asphalt, it's an old roof and "at or near it's effective service life". Other obvious stuff too like nails popping through the top. Also, how wide is the gap between the tabs? Is it a good deal wider than when it was new? That's telling me the shingles have dried out and shrunk. They'll start disintegrating soon. Multiple layers of shingles will also retain heat and shorten the life. Shingling over an existing layer may very well void the manufacturer's warranty so the only the 1 year installer's warranty is left and good luck with that.

IMHO, sun light and poorly vented attics are the big killers. Lots of tree shade can easily add 10 years to the life of a roof and all you have to deal with is algae/moss and that's easy to kill. 100% direct sunlight, all the time will shorten it's life. It's a good idea to choose a light colored shingle with a lot of direct sunlight.

I see a lot of bad roofs in older homes and the culprit is usually overheating attics. Attic ventilation is so important. I've seen where owners have closed in gable vents to keep birds out instead of just putting in a new screen. They cooked the roof. Usually all the old roofs have are gable vents. I've also seen reflection from dormer windows cook the shingles directly in front of them in a couple years.

As they dry out, they get thinner too. You can buy a shingle gauge that measures the thickness. If you can slide the gauge all the way in, the roof is close to done.

Thanks Sniper. Interesting stuff

[joe1086]

He said that the soffit and ridge vents would work better. 

But could he have been right? I'm no expert but we were told the same thing. Incoming air from the gable vents means less air being drawn in from the soffits so you have uneven airflow. We sealed our gable vents after the ridge vent was installed.

[barnowl]

My theory is that the more square inches of ventilation, the better. And soffit vents at my home are very narrow.




https://www.finehomebuilding.com/2012/01...able-vents

[meackerman]

Here is part of the study guide I used for licensing. A lot of real good information in it.

I was called to be an expert witness for an insurance company who was being sued by the home owner because the insurance company denied a hail damage claim. The claim was fraudulent and I used this document to back me up. The insurance company won. It was an old roof that needed replacing so the home owner went on the roof with a ball peen hammer and damaged his own roof.

I can tell you what a home inspector looks for:

Any exposed fiberglass on the edges of the shingles, cracks, deformation and granular loss. You can see the granules in the rain gutters and on the ground at the downspouts. The granules act as a heat sink and help cool the shingles and help reflect sunlight. When they're coming off, your shingle looses it's protection from sunlight and heat, including heat from the attic. So we like to see uniform granule cover. If I can see asphalt, it's an old roof and "at or near it's effective service life". Other obvious stuff too like nails popping through the top. Also, how wide is the gap between the tabs? Is it a good deal wider than when it was new? That's telling me the shingles have dried out and shrunk. They'll start disintegrating soon. Multiple layers of shingles will also retain heat and shorten the life. Shingling over an existing layer may very well void the manufacturer's warranty so the only the 1 year installer's warranty is left and good luck with that.

IMHO, sun light and poorly vented attics are the big killers. Lots of tree shade can easily add 10 years to the life of a roof and all you have to deal with is algae/moss and that's easy to kill. 100% direct sunlight, all the time will shorten it's life. It's a good idea to choose a light colored shingle with a lot of direct sunlight.

I see a lot of bad roofs in older homes and the culprit is usually overheating attics. Attic ventilation is so important. I've seen where owners have closed in gable vents to keep birds out instead of just putting in a new screen. They cooked the roof. Usually all the old roofs have are gable vents. I've also seen reflection from dormer windows cook the shingles directly in front of them in a couple years.

As they dry out, they get thinner too. You can buy a shingle gauge that measures the thickness. If you can slide the gauge all the way in, the roof is close to done.

when we bought our roof it was maybe 6-7 years old, but when they reroofed it the only upper vent was one gable end vent, on a 3200 sq ft single story.  Full sun all day long, except where the solar panels are.

Lots of eave vents, but no where for the hot air to escape to.  Initially I put in a powered vent just to have something, later I ripped open the ridge and put on ridge vent (and cranked the powered vent's thermostat up)  bet I lost a lot of life of the shingles, they still look good, but there's always granules in my gutter.

[meackerman]

But could he have been right? I'm no expert but we were told the same thing. Incoming air from the gable vents means less air being drawn in from the soffits so you have uneven airflow. We sealed our gable vents after the ridge vent was installed.

I've heard the same thing from pretty much everyone I've talked to.  Pick a venting strategy and go with just that.  

Course I haven't sealed up my gable vent but now with the fires getting so close this year, I'm thinking I should if nothing else to keep any embers from entering the vent if we do have a fire that's close by.

[Snipe Hunter]

Funny you should mention that.

A couple of years ago, we decided to re-roof. Invited a number o local contractors to bid.

This was to be the second re-roof since the house was built, in 1970.... 48 years. 

One was a young rep from a construction company in the next state over. Seriously.

Well polished young man, who seamed to touch all the bases.... until.... he said that we should close off the gable vents.

(we have soffit vents, a ridge vent since the last re-roof, and two gable vents.) 

I asked why. He said that the soffit and ridge vents would work better. 

After explaining that they've all been there since 1970, I asked how long he'd been selling roofing.... his answer.... four months. 


We did not hire his company. Oh, and their price was twice the price of others. 

Well, he was right.

Leaving in the gable vents open, disrupts the upward flow from soffit to to ridge and creates dead air areas. Not saying you would have a problem, just saying that it's better to close them off.

[barnowl]

Well, he was right.

Leaving in the gable vents open, disrupts the upward flow from soffit to to ridge and creates dead air areas. Not saying you would have a problem, just saying that it's better to close them off.

After our conversation, I looked again at the gable vents.

They are small, and so high, they might as well be ridge vents.

[JTTHECLOCKMAN]

Just had a new roof and siding and they left gable vents and ridge vent. They never heard of this and they are Certainteed certified. So they stay. I believe you can never have enough ventilation in attic. Heat destroys roof.

[Snipe Hunter]

Just had a new roof and siding and they left gable vents and ridge vent. They never heard of this and they are Certainteed certified. So they stay. I believe you can never have enough ventilation in attic. Heat destroys roof.

They weren't paying attention.
There's reasons homes aren't built with gable vents anymore. The same reason we don't poke holes in the middle of garden hoses.

[whatline]

A lot of the things people used to look for like curling corners happened more with asphalt/ felt shingles. Not so much with fiberglass. All the other things mentioned exposed fiberglass, missing granules Nail pops etc are spot on. As for venting it’s a big deal and not well understood. The reason to close off the gable vents is because they interfere with convection which is what makes the soffit and ridge vent work properly. It is important to have that air circulation. If replacing the roof opt for ice water shield at valleys and eaves..make sure the eave ply extends back beyond The exterior walls. Go with synthetic underlayment as well