I'm thinking of metal roofing my house. I'm sick of shingles and everything else I own is tinned. My question is would go right over the shingles or would you tear them off? Roof is in good shape and shingles aren't curled and roof doesn't leak. I just to replace them but still in good shape.

Why tear them off and what are do's and don't.

Leave them on.

Now you went and did it.

I dont doubt you experience but can you elaborate a little more so I can understand how it fails. The roofing screws generally get screwed into 2x4 that are put on on top of the roofing and insulation rolled over that then steel put on top of the insulation, from what I understood. So the screws dont come in contact with the roofing or I dont see how they would. Is it the fasteners that hold the 2x4s down that get eaten up? Or is it people putting the steel directly on the shingles skipping the wood on top causing the problem.

My house is ready for a new roof and im still deciding what I want to go with.

Vince shingles with 2x4’s screwed into the existing trusses 2’ o/c. And forget about any issues..

Why 2x4? For both of you.

Personally I wouldn't want the steel expanding and contracting on the abrasive roofing shingles scratching the pain up and the moisture that forms under the steel when it sweets rusting it out from underneath. But that was my amateur hour idea on the topic. Looking forward to the other explanations.

If this is true, then the fasteners applied to secure the shingles wouldn't survive.
There is a difference in the amount of corrosion between hot dipped and EG nails.

I am going to guess that Lefty is describing a situation where the fastener is not coated and the chemicals in the shingles will eat through the fasteners in time.

The same thing happens with nails or untreated screws in pressure treated lumber if they are not galvanized.

I Remember working one job where the roof decking was spec'd to be pressure treated for some reason, and we had to nail it off with 6d stainless nails. Pretty darn spendy !

1X4

Yep .

Leftlane for the win

Big difference, EG sucks.

1 x 4 purlins over the shingles nailed into the rafters/trusses and screw the steel panels into the purlins.

We always tear off completely down to decking substrate. I see guys installing lath over shingles then metal, but it avoids warranties. I personally would not do it. You also want to properly flash plumbing vent pipes, bath exhaust vents, and skylights. Ridge vent and eave intake are a must to ensure a long lasting roof and roof deck.

Don't know metal vs shingle but as a framer my question would be one of weight on the frame structure.

Only reason I can think of for a 2 x 4 purlin is if you were going to use snow guards. Most manufactures want a 1.5" screw for their guards.

If you want to build a complete system without tearing off you would
Cut back the edges of shingles that overhang
Pull up the existing pipe flashings and vents without damaging the existing roof.
Install your underlayment. I used to do two layers of 30 lb. Ice and water block if that's what you use in your area. I don't like synthetic felts but they seem to be all the rage and cheaper.
Seal any roof penetrations.
We always suspended the roof boards by installing 1/4 in lath up the truss vertically. This allowed any water or condensation to travel under the board instead of pool behind it.
Install your 1x4 around the perimeter around the pipe flashings and anywhere else that needs supported.
Seal up the woods installed the best you can so you don't get bats.
Install hip and ridge attachments.
Cut any venting and support if needed.
Trim as needed so that roof flashing will work with existing counter flashings.
Install metal panels so that you work into the prevailing winds.
Fold up the end of the panel under the flashings and the ridge at 90° angle. This makes a water dam.
Choose the correct sealant. I don't like to use very much because there is a lot of expansion and contraction
Strategically removing corners on metal panels and flashing can help to eliminate any capillary effect of the water.

Hoss? What is insurance paying for 1 layer walker and steep.? In a populated area.

Well you might want reconsider. This just popped up on my feed.

https://www.facebook.com/share/17tGdfV52u/

On June 4, 2026, at approximately 9:45 a.m., the Taylor County Sheriff's Office received a complaint regarding the theft of a metal roof from a vacant residence located on S.B. Eubanks Road in Reynolds, Georgia.
Sheriff's Office investigators immediately responded and began processing the scene. Through diligent investigative efforts, investigators were able to identify those responsible and, within approximately 30 hours of receiving the complaint, successfully solve the case.
As a result of the investigation, Jason Childree of Wainwright Road, Butler, Georgia, was identified and arrested. Childree has been charged with Theft by Taking, Burglary, Criminal Trespass, and Criminal Damage to Property.
Investigators have also identified three additional suspects involved in this incident. Warrants are being obtained, and arrests are expected in the coming days.
Sheriff John Sawyer stated, "In my 35-year law enforcement career, I have never seen anyone steal the roof off of a house. This case demonstrates the dedication and determination of our investigators who worked tirelessly to identify those responsible and bring them to justice."
Sheriff Sawyer specifically credited Chief Investigator Matt Binkley and Major Chad Payne for their outstanding investigative work and commitment to solving the case.
Sheriff Sawyer further stated, "Anyone who steals from the citizens of Taylor County can expect to be arrested and prosecuted to the fullest extent of the law. We will not tolerate criminal activity that victimizes our constituents."
The investigation remains active, and additional arrests are forthcoming.

Not much experience with quality snow guard. I assume you could ancor in the truss.
I mistake roofer make most often in heavy snow areas is not installing a snow guard, of some sort, behind abs soil stacks.