Steel Roof Options

In the process of getting quotes for steel roof to go over 1 layer of shingles. Location is southern NH.
Low quote is for standing seam ABC manufacturer, SL-16 panels. 29 guage, sheet is fastened to roof.

Higher quality (and 50% more) is for 24 guage, cut at site from roll, sheets are held down by clips, clips are fastened to roof, also standing seam.
Any opinions on either of these?

I will need to walk on roof at times to clean chimney and paint.



I would ask contractors to let you take a look at some of the completed work so you can take a look at both profiles on the roof and compare.

Also find out about the warranty details for product rust protection, paint coating, and labor - water tightness.

Thanks for the reply.
They will be supplying references and such.
I was looking to see if anyone had opinions on
the different options, 29 guage vs 24 guage.

First I would recommend removing the shingles.

Then I would recommend copper, stainless, or terne coated for the metal. They can be soldered tight at the penetrations. Painted steel and aluminum are sealed with adhesives and caulk.

Then I recommend someone who has sheet metal experience and has been installing metal roofing for awhile. It’s not the same as installing asphalt shingles.

Of your two choices, I would go with the heavy guage that clips to the decking.

24 GA is far superior and generally has less “oil canning” after installation (rippling effect).Longevity would be significantly longer.

The gauge difference might not seam like much I suggest getting a sample of each to see for yourself.

24 GA Would be more conducive to walk on however be careful metal can be very hazardous to traverse.

I would refer you to take a look at a product called DECRA. It is a stone coated steel panel. It is just another option for you to consider.

I agree with other posters. Take off the shingles to a clean deck.

Install a slip sheet.

I wouldn’t consider 29 Guage for a roof application. Honestly, I wouldn’t consider 29 guage for anything of value.

In Texas we normally use 26 guage on our sheet metal panels.

Guys are telling you the right thing:

Tear off existing shingles, as if you do not, they will “telegraph” through metal panels - you’ll be able to see horizontal lines denting through your metal roof.

Honestly, i would not deal with either one of these two roofers, as the ignored telling you about the need for tear off, which means the don’t care.
Metal roof is all about looks and longevity. If shingles don’t come off, you loose both. Stone granules will scratch through paint on bottom side of the panels, causing them to rust.

Now, would you really trust guys who did not tell you that?

Any way, as for the gauge, 29 ga is just too thin. Go with 26 or 24, or better yet, go with Aluminum.
Yes, it will be more expansive, but you won’t have to worry about rusting. Definitely tear off.

And don’t just go for references, visit job sites, talk to people. Ask your neighbors. Search the internet.

Good luck.

idutri - I would call the two you got quote’s from tell’em you are thinking about getting a tear-off. See what they say.

If you were my customer and I read you as not wanting a tear-off. I would mold my sale that gives you what you want and what I’m willing to do. Who would want to pass? Its kinda like two jobs in one.

If you want them upside down, I’ll give it to you, warranty may change but upside down they will be.

I slightly disagree with Roofer R… A customer might ask for one thing & I will answer it, then possibly counter with other info so they are better educated.

Now, if the customer asked me for a ‘cheaper way’ & wanted to leave the shingles on, then I said "not good, do full tear off because _______ " & they stated the desire to still skip the tear off, well that’s their concern & not mine. I gave my opinions, therefore my warranty & expectations will match what I stated up front.

BTW, what’s the pitch of your house? An easily walkable 6:12 in shingles is dangerous territory for metal of any type (exception: Decra… it’s stone coated metal).


You must not have a lot of experience with metal roofs. They ALL can be installed on 4:12 pitch. Some, even on 3:12, but i would not go below 4:12.

Decra, or any stone stone-coated for that matter, in so different than painted aluminum or steel when it comes to pitch requirement. In fact i would hesitate putting most stone-coated metal roofs on anything less then 5:12 Here is a stone coated on 5:12 -

Any way, Idutri was asking about standing seam, which can easily go on 3:12. Bear in mind that some standing seam roofs are 1:12 and are water-tight…

[quote=“rooferama”]I agree with other posters. Take off the shingles to a clean deck.

Install a slip sheet.

I wouldn’t consider 29 Guage for a roof application. Honestly, I wouldn’t consider 29 guage for anything of value.

In Texas we normally use 26 guage on our sheet metal panels.[/quote]

Maybe in residential applications you might use 26 ga.; I certainly wouldn’t. Then again, I’m used to commercial construction where the standard is 24 ga. and the upgrade is 22 ga. Personally, I wouldn’t use foil…uh…I mean 29 ga. metal for anything other than maybe a tool shed or dog house. Even then, I wouldn’t like how beat up it looked after a week or two.

What I meant about a 6:12 being dangerous is for walkability… customer stated he would be going up for maintenance issues.

A 6:12 in metal is dangerous territory.

to Ranch,
well, sorry… did not see any where about about customer going up on the roof… anyway, with metal roof there really should not be a need for home-owner to go up there as metal roofs really require no maintenance, given they are installed correctly. Although a lot of people ask us if hey can walk on metal roof.

I’m still trying to figure out the nature of such question… really, why would you want to go up on their roof??? I’ve never been on my own roof - it does not leak, so i don’t go up there :slight_smile:

Thanks for the great feedback!
As for going over the shingles,
one company is going to put down 5/8" strapping and the clips/roofing are attached to this, the other is going to put down tri-flex so in both cases, the metal is not directly on the shingles per se.
As for walking on the roof,
on the 2 story part, I have a center chimney, the clean out in the basement is too low for flexible poles so I have to clean it out from the roof.
on the 1 story part which is perpendicular to the 2 story, I need to stand on parts of this to put stain on the siding of the second floor.
Thanks for reading and keep the comments coming.

I just installed some 26 ga Image II panels, they are nice looking.

This will show you some of the panels that are available.

Ranch - It would be silly not to tell the homeowner what the ‘better’ way to do something was. The point I was trying to make was that if the homeowner had economic factors playing into their choices. And was interested in the cheaper way, or the way they wanted things. As long as I was comfortable I would mold the sale to fit their needs. BTW I’ve never put’em on upside down. Easiest example I could think of. :slight_smile:

If you like the looks of DECRA it would be a great option for you. It is a heavy gauge metal that can be layed over the existing asphalt with out any use of a backing board. It is stone coated therefore it is like velcro under your feet when you walk on it. A few concerns I have with layovers are #1 ice back up because of the lack of ice guard adhered to the deck. #2 Detailed flashings. #3 weight However DECRA only weighs about 125 lbs per square. If you haven’t seen it I recommend you look at it. It is for everyone but it is a nice product. I would recommend looking at one that has already been installed in your area. Reason being the seams are very noticable as some people don’t like that look. it is very similiar to the seams in vinyl siding if you will.

Well, here’s MY three main concerns with going over the asphalt without removing it:

  1. Metal lasts a LONG time. Much longer than shingles. How many opportunities do you think you’ll have to fully examine the roof deck? …Especially if you’ve got metal going up. Why not go ahead & get a fully cleaned off roof, peform any repairs on an as needed basis, THEN go into it with your new product.

  2. The cost is really not that great, @ least here in my market. You’re talking about maybe 25.00 per square (height & pitch dependant + a few other job dependant factors). That means that on a 37 square roof (a size most of us roofers will agree is on the "slightly average size"), you're talking about 925.00. As a percentage of the total job, this is probably less than 5% in most markets.

  3. Marketability. If I was looking @ a house for sale & knew it had a 2nd layer, I’d wonder what other areas were done halfassed. Plus, if a leak ever DID develop, I’d have the joy of working through the metal & THEN digging through the asphalt to see what was going on.