Off topic- Roofing Tin over asphalt shingles?

[Bruce L]

Putting this question out there,asphalt shingles are curling up,several are missing on house,need to put new roof on. Should I strip shingles as best as possible,then strap,or can I just strap over the existing shingles? Thanks in advance

[Pdiamond]

If this is the first time you are redoing the roof you can put on the metal roof right on top of the shingles. The Amish do it around here all the time.

[phil-t]

Just consider your roof framing/design and the additional weight of the metal. Strip the shingles if weight is a concern.

[maple flats]

Part of that will depend on the pitch, Steel roofing sheds snow much better, but if the pitch is only 4/12 or 5/12 it may not do it quite as well. My sugarhouse is 6/12 pitch and snow rarely gets more than 6-8" deep before it slides off. My shop is a hip roof, the top is only 3.5/12 pitch, it holds snow much longer, the steeper angle o9n the lower roof (24/12) never holds more than 3-4 inches before it slides off.
By the way the pitch of a roof for those who may not know is stated as the " rise/ft, for example 4/12 rises 4" every 12.

[n8hutch]

I have A steel Roof over asphalt Shingles. The house was like that when I bought it. It's not a huge Big Deal, that being Said most of the roofing guys I know recommend against it. I don't believe that its frowned on because they want the extra dough to strip the roof. It's a ****ty Job if you have ever done one.

[steve J]

I just had a metal roof installed on my log cabin over the shingles. Your adding very little weight because over the years your shingles have broken down and loss weight so you bascily hae no more weight than when shingles were installed years ago.

[Sunday Rock Maple]

The color of painted roofing installed on slats over shingles will fade due to heat build up -- that's why the roofers recommend against it.

[motowbrowne]

Just put steel on my house last year and did it right over the shingles. I laid 1/4" fanfold insulation over the shingles and secured with plastic cap nails. Steel over that. I can see that there might be pros and cons to both options, but for me, not having to tear off, haul, and pay to dispose of the shingles made leaving them a no-brainer.

[DrTimPerkins]

Metal roofing over shingles isn't a problem as long as the roof can take the additional load (not likely a problem). You may need to trim some of the shingles if they are curled/cupped really badly, otherwise just fasten down some strapping and use long screws to go through the metal/strapping/shingles/decking and get well into the roof rafters. If you're paying to get it done, the main difference is cost. Removing shingles is a pain in the butt and generates a good deal of waste material to be disposed of. Contractors charge accordingly.

[Wmmaple]

You might want to check the steel manufacturers warranty. With some companies it voids the warranty if installed over shingles.

[DrTimPerkins]

One other thing...if your cellphone coverage is weak is spotty, a metal roof can kill it or make it worse. Every now and then my phone gps will put me in Indiana or Columbia, South America. ;)

[Wannabe]

I was a roofer for 12 years(yeah I know, what a dumb a$$ lol), we put a LOT of metal on over shingles. We mostly 'stripped' the roof with 1"x4"s or 2"x4"s first, over the shingles (never seen the color fade because of this, not saying it cant happen). If you lay the metal right on top of the shingles you will see waves from the old shingles underneath(not a big deal if looks don't matter). Another benefit of putting the wood down first is you know EVERY screw is going to 'bite' into something good(you cant tell what the shape of the decking is under the shingles).

[3GoatHill]

What about Ondura? Anybody have any experience with it?

[wiam]

What about Ondura? Anybody have any experience with it?

DON’T. The company name is new. Product used to be called Onduline. “Lifetime” guarantee. Then they “went out of business” before you can collect. Does not last more than 15years before it starts flaking.

[Bruce L]

Thanks for the input everyone,got price on tin,strapping,valley,screws etc. today,wasn’t as bad as expected. Considering making the house tighter with new windows,that was quite a scare,quote was $44,000.00!!!!! for 9 windows,and 5 patio doors,nothing too big or fancy. Thinking I could get the whole house spray foamed for a lot less money and get more bang for the buck

[tcross]

in reality, when you replace your windows you aren't doing a whole heck of a lot to improve your thermal envelope unless your current windows are really, really bad/leaky. it's glass. the u value or r value (whatever you go by depending on where you are located) isn't much. just two panes of glass with a little bit of gas in between. you're much better off with proper insulation. a layer or 1" or 2" foam on the outside, under the siding, or more insulation win the ceilings, is way, way better money spent!

[Ultimatetreehugger]

That's a price gouge quote. 5000 max if you pay for material.

[maple flats]

Get more quotes. It was 25 years ago, but I used to do siding, insulation and replacement windows. That price is about 9x what we got to do 34 windows in one house in 1992. In another big job we did 21 windows for about $5000 (larger windows). While the prices on the windows has climbed, the window cost is only about 20% higher than what it was 30 yrs ago. In my retirement I had 14 windows replaced 3 years ago in a rental duplex I own, it cost $3900, windows and labor. Patio doors are not that much more than what it costs to replace 2 big double hungs. The difference there might be if headers need to be fixed. Then materials rise a little and labor a lot.

[maple flats]

How old is your house? If the existing windows have (or had) window balance weights in side channels, have that removed and insulated. Those weight cavities are always a huge heat loss area. Doing windows but not removing weights and filling the cavities with insulation will result in very little heat loss improvement.

[phil-t]

I did windows in our 1964 vintage home, had a contractor buddy come over and showed me how to measure, I did the measuring for 16 windows, ordered from Lowes, he came back and helped me install one, I did the rest. Used the low expanding foam insulation to seal all gaps and channels. I did the entire house in 2 days. Found it to be a relatively easy task. Buddy came back and I worked with him to do vinyl siding with sheet insulation underneath. Best thing I ever did to a home. Also added blown insulation, DIY, to the attic. We added ventilation there as well. I think total investment in our ~1600 sq.ft. home was less than 4k $. Stillhave to doors, at some point.

[BAP]

Bruce is in Canada so that is going to make a difference in cost.

[johnallin]

Bruce is in Canada so that is going to make a difference in cost.

Sure as h••l isn’t $35,000 difference!! Canadian dollar is about .75 of the US Dollar these days.
I mfg and supply aluminum building products to window companies all over the eastern US.
Most legit companies are lucky to get $350-400 per opening these days!

[BAP]

Sure as h••l isn’t $35,000 difference!! Canadian dollar is about .75 of the US Dollar these days.
I mfg and supply aluminum building products to window companies all over the eastern US.
Most legit companies are lucky to get $350-400 per opening these days!
I not saying that the quote isn’t way too high. What I am saying is when posters from the US start throwing numbers around, you have to remember that you have to automatically add at least 25% more due to exchange rate.

[fred]

i not saying that the quote isn’t way too high. What i am saying is when posters from the us start throwing numbers around, you have to remember that you have to automatically add at least 25% more due to exchange rate.

its actually 40% when you go the other way.

[johnallin]

Fred, more like 33.3% . 75 x 1.33 = 99.75.
But not bad for someone who doesn't like Leader Clear Presses.....<big grin>

[fred]

john we have a great ophthalmologist in town now. you dont have to look through the press anymore. <bigger grin>

[johnallin]

john we have a great ophthalmologist in town now. you dont have to look through the press anymore. <bigger grin>

But everything is so much easier to see. <even bigger grin>