Metal roof over shingles roof.

[clemsonfor]

FWIW...
They make roofing screws that have zinc caps (domed washers) that protect the elasticized material that seals around the screw under the cap...they're sold most places that sell 5V and other metal roofing panels...

Yea but the sides are still partially exposed and rubber also degrads even when not exposed. Those do help.

Much better than lead headed nails. Hehe

 

[EddieWalker]

The fasteners on metal roofs will not last as long as the roof, you will have to rescrew at some point as UV and pollution etc will degrade that rubber.

I disagree, but I'm not sure if we are splitting hairs or if we are night and day apart in this. It is my experience that if you use quality screws, they will last a lifetime. I've seen 40 and 50 year warranties on them, and some will even come with a lifetime warrantee. I don't know how many years a lifetime is, but it's got to be at least as long as the metal will last.

For comparison, how long will the rubber from a tire, an inner tube or even roofing membrane last if left out in the sun for decades? Do they ever break down and decompose?

When installed properly, with the rubber barely bulging, those screws will last much longer then the best shingles out there.

 

[clemsonfor]

I disagree, but I'm not sure if we are splitting hairs or if we are night and day apart in this. It is my experience that if you use quality screws, they will last a lifetime. I've seen 40 and 50 year warranties on them, and some will even come with a lifetime warrantee. I don't know how many years a lifetime is, but it's got to be at least as long as the metal will last.

For comparison, how long will the rubber from a tire, an inner tube or even roofing membrane last if left out in the sun for decades? Do they ever break down and decompose?

When installed properly, with the rubber barely bulging, those screws will last much longer then the best shingles out there.

The ones I have seen were probably cheap ones off sheds that I have seen. Quality ones you are right probably are a lot better. And at this point in my life even while I am what some consider young, I may not even live 50 more years.

And yes tires left out in the sun and exposed do break down. New rubber more than old. That's why your old hard dry rotted tires don't hold air anymore. I am not arguing with you here though. I am on your side as you have much more real world experience than I do. And I do value your opinion here.

 

[atsah]

When installed properly, with the rubber barely bulging, those screws will last much longer then the best shingles out there.

Depends on the environment, extreme cold winters do a job on roofing screws up here, if you get 10 years without leaks you have done well.

 

[clemsonfor]

Depends on the environment, extreme cold winters do a job on roofing screws up here, if you get 10 years without leaks you have done well.

I know the one on my big boat shed are toast. It's one of those metal carport awning type installed ones. Way bigger than a normal carport. I can park a buss under it. I have lived here 10 years and it was well there before that. At least 15 years I bet. So it's at least 20 years old. Lots of the rubber grommets on it are decomposing. BUT they probably had the crap tightened out of them, I can even tell looking at some of them that was the case. And it being a metal shed they probably were the cheapest quality they can get by the 55gallon drum full I am sure.

But again as I eluded too, I have next to none if never actually been on top of a screwed metal roof home of any age. Going of experience of what I have seen on sheds and metal buildings.

 

[wwdiii]

I am no expert by any means. When I do my roof which has shingles on it. I am going to lay 1x4s, then that reflective barrier or whatever its called. I know what it is but not sure I know the name. Then put my metal on top. Shingles would seem to be pretty decent insulation. It gets hot in Texas.

 

[goeduck]

One layer of composition shingles would not bother me much but I tend to take everything down to the basics when I do something like that.

 

[pmsmechanic]

Our house has a layer of cedar shakes then a layer of asphalt shingles and then just before we bought the place a fly by nighter talked the previous owners into aluminum shingles which were installed over the previous two layers. When the time comes all three layers are getting removed and a ribbed tin roof is going to be installed. I enjoy the sound of rain on a tin roof.

 

[Lnk]

We put a metal roof over the original shingles of our ranch. All we did was trim 4" all the way around the perimeter before putting on the metal. Did this with circular saw set to 1/4". One thing we did was to predrill the stack of metal every two feet starting 8" from the bottom, on top of the ribs. The idea being all the screws will line up, which they did, and the water never stays on top of the ribs. My roof is 1/12 pitch and each side is 16 x 77, with a fake former in the front. It took two of us 3 days, including trimming vents and chimney (metal piping). We also did the edge trim on either end of the house as well as around the corner.

We have had no leaks at all. The screws have the rubber washer and the washer is coated with something color coated same color as the roof. Which I believe is powder coated. My roof is forest green. We bought ours from TN metal products, no affiliation. They make the roofing on site from rolls of the coated metal. I believe my material cost in 2012 was around $2400 dollars. I will never us another shingle
again.

Noise, not really any different from the shingle roof before the metal. Have not heard any hail, though it has hailed a couple times. Small hail. No damage.

Hope this helps.

 

[Stimw]

I had a new metal roof put on last year/spring by a licenced roofer, permitted and inspected.
He put synthetic felt down over shingles and screwed roof down with no furring strips.
He also screwed it down on the ribs and said it was engineer approved fastening.