What is your opinion?

Many of the homes around here are older, most were shingled when built. Over the years steel has become a popular reroof product due to snow and life span. The problem is I am finding a lot of homes that have had the steel placed directly over the shingles. When I find this I almost always also find pulled nails or screws (fastener type depends when the steel was installed), lifted seams, and steel sheets that have waves in them. When I find this I write it up as a “substandard” roofing install. I had a discussion the other day with a “contractor” who wasn’t happy that I wrote up his recent job. I explained to him that I know standards allow for 2 layers of roofing but that applies more to shingles and I could show him pictures of multiple steel failures due to this type of install. We ended up agreeing to disagree and left it at that.
My question is does anybody run into this and how do you handle it? My personal theory is do a tear off, check the sheeting and start with a clean slate.

Based on your description, I would agree. The composition shingles do not provide a flat or solid surface to secure the metal panels to IMO. This means there will always be a higher amount of give or flex during temperature changes and due to wind than you would see on a correct installation.

Your description of your method of reporting this sounds more than fair. Perhaps on some of the roofs if the damage/defects are great enough a complete tear off and reinstallation may even be warranted. Do you have any photos?

Was the overlay permitted and signed off?


In my area most steel roofs have been installed very poorly .
Most have been down by owner and a few friends of incorrectly.
Lots of caulk crooked incorrect fastening .

Installation Guides

This is what happens when you don’t do it right.

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Moms Kitchen June 3 2013 148.JPG

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As far as building codes, there aren’t any here. When you build you only have to meet NEC or what ever the electrical inspector wants for that day, and county septic which only covers the tank and drain field. I will see if I can dig up some old photos later today. I just stopped by the house quick, back to work.

Scott, I explain to my clients that because the steel roofing panels are generally 3 feet wide and the roof rafters are framed 16 O/C there is no way every panel will land on a rafter and be properly secured. When I installed steel roofs I always stripped the roof, layed down the moisture barrier (usually 30# felt) , installed strapping and then the panels would be screwed through the strapping.

I’ve seen way to many roofs as you described that end up lifting in high winds.

That is correct. We have the same issue here and that is why I showed the very bright shinny nails that missed all the engineered truss.
Other thing that is forgotten in the Snow belt area is crickets or protection to vent stacks. The one picture shows the results.

All roofing materials must be installed in accordance with the manufacturer’s installation instructions. I don’t know of any that allow installation over shingles in Vero Beach, FL.

Kevin, what are your concerns with the vent stack boot ?

Ice broke the vent clean in half in the Attic. That is why that straight on shot of the vent is not vertical.

I attended Firstone roofing product school a couple of years back and asked the specific question can or should one lay metal roofing over asphalt shingles as I was considering metal on my own roof and the instructor stated no Metal should be laid over asphalt because of the movment expansion and contracton will scratch the paint and create rust from the bottom side of the metal

Directly onto the shingles without purlins causes even more trouble but that is one Charley.

I see, maybe they should have installed these.


Charlie, I could never understand why someone would go through the expense of installing a metal roof and lay it down over crappy old shingles but I see it all the time in my area. After 4-5 years they all start developing problems.

I prefer a cricket of metal to divert the snow around the stack or this one.
Product Description:

THE CRICKET ELIMINATOR: The smaller of three models recommended for lighter snow conditions. This ingenious product adds support and strength to your smaller vent pipes while the innovative fin design cuts through and assists in shedding the snow and ice from your roof. VentSaver FB-151 series is made from non-corrosive powder-coated aluminum with a pre-punched stainless steel strap to fit smaller sizes of pipe from 1.5" - 4". Also provided are stainless steel nuts, bolts and heavy duty 1 1/2" lag screws. It protects a standing profile of 6". Installation is quick and easy.

It looks like a good idea.
But for me to many holes in the roof.

Yes you are correct as I don’t recommend this one. I recommend a metal cricket only that works like an ice breaker not a ice stopper.

I’m in Florida and don’t have that issue, but does the snow get so bad as to put those pipes over ?
If so ! I would believe that the reinforcing should had been within the attic area.
I could be wrong.