tin over shingles ???

[rburke65]

IDK. They just did a house down the road and I he ran 2x4s atop the shingles then the "tin".

 

[NUTTSGT]

I would think you and your insurance company would have risk management concern of fire. I have seen the difficulty of extinguishing a fire with asphalt shingles under a metal roof. The fire keeps rekindling as the shingles hold heat and are a fuel source. I think the other expressed concerns of roof loading and less stable installation are valid as well.

Never had much of an issue with asphalt shingles burning under the metal roofs as we have had with wood shake shingles under standing seam.

 

[bczygan]

I have been watching people overlaying a shingle roofs with tin , one guy laid the tin over the shingles & nailed thru the old shingles into plywood sheeting another guy nailed 1'' x4'' strips of wood across the roof every 2' Then placed tin on the roof & nailed to 1x4's . Which is best ? By putting strips on you may get some ventilation ??

I would never put anything over a layer of shingles, even shingles.

Strip to the decking so you can inspect it.

A good and proper base makes the job correct.

Bill

 

[Jazz1]

laying the tin over shingles makes it quieter in cabin during rain. As well if I removed shingles they would have to be disposed of which means more cleaning up and haul them down river to shore and load on truck...no thanks

 

[Falcon67]

I can add this about leaving shingles and offered FWIW: At our old house, the "shed" garage had some really old shingles on it. Looked bad. So much so that the insurance co would not write a policy until they were replaced. It was 16x22 so not a big deal. I stripped off one layer only to find another base layer of old green shingles likely from the 70s when the thing was slapped together. Maybe even earlier - construction looked late 60s, early 70s at least. The greenies looked good, and I was pressed for time so the new Owens 3 tabs went right over the top. That was in 1997 and that roof still has both layers and looks perfectly fine - no leaks, no curls, been through two big hail storms.

So I can see a case for going right over the top, depending on location. Maybe not so much here where a roof deck can run 160F+ in the summer.

Also one reason I'm not too keen on metal is the repair. I can fix three tabs, not going to catch me up on metal.

 

[83VillageRepair]

What's the point of misrepresenting sheet steel as "tin". Might as well call it Magnesium, or Titanium, or Kryptonite. Any of those names would be just as incorrect.

It ain't tin.

Around here they call it roofing iron