Painting a Galvanized Metal Roof?

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Woodtroll
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Painting a Galvanized Metal Roof?

Post by Woodtroll »

Way OT here, but I'm betting someone can help...

I put a galvanized metal (the old 5-V "tin" roof) on our farmhouse when we moved into it almost 35 years ago. I've painted it a couple times since with an alkyd enamel paint that stuck okay to the rusted parts, but sloughed quickly from the parts with zinc still on them. Now it's in dire need of painting again, but it still has some patches with zinc left on them. I'd like to paint the roof again, preferably with an epoxy or something durable, to make it last this time, even if it is expensive or time-consuming.

Has anyone had any good experiences doing this, and what product(s) would you recommend?

Many thanks!
Regan
Running the ridges and rivers of Virginia's southern Appalachians
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GunnyMack
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Re: Painting a Galvanized Metal Roof?

Post by GunnyMack »

I would suggest a real paint store- NOT home depot or lowes. I'm sure there is a paint for steel roofing .I would try Benjamin Moore.
We used to use a tar based aluminum coating on flat roof's years ago.
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Woodtroll
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Re: Painting a Galvanized Metal Roof?

Post by Woodtroll »

Thank you, GunnyMack, I appreciate the help. I forgot to mention that my wife wants a light blue color, not silver, which rules out the usual fibered metal silver "tin roof" paint that many of us are all too familiar with! (Flashbacks to summer barn roof painting as a teen...)
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Pete44ru
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Re: Painting a Galvanized Metal Roof?

Post by Pete44ru »

.

Here's what Sherman-Williams has to say about it:

https://homeguides.sfgate.com/paint-gal ... 97939.html

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vancelw
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Re: Painting a Galvanized Metal Roof?

Post by vancelw »

For what good quality paint or epoxy costs, you could almost put new sheet metal up. That is, provided you could do your own labor.

You might try a light acid wash on the shiney parts before painting. Don't breathe the lead fumes.
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GunnyMack
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Re: Painting a Galvanized Metal Roof?

Post by GunnyMack »

vancelw wrote:
Sat Aug 10, 2019 5:34 pm
For what good quality paint or epoxy costs, you could almost put new sheet metal up. That is, provided you could do your own labor.

You might try a light acid wash on the shiney parts before painting. Don't breathe the lead fumes.
Very good point! When I worked at the lumberyard one of the suppliers had about 25 different colors, 25 yr warranty AND light blue!
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2ndovc
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Re: Painting a Galvanized Metal Roof?

Post by 2ndovc »

GunnyMack wrote:
Sat Aug 10, 2019 5:51 pm
vancelw wrote:
Sat Aug 10, 2019 5:34 pm
For what good quality paint or epoxy costs, you could almost put new sheet metal up. That is, provided you could do your own labor.

You might try a light acid wash on the shiney parts before painting. Don't breathe the lead fumes.
Very good point! When I worked at the lumberyard one of the suppliers had about 25 different colors, 25 yr warranty AND light blue!
Totally agree, I have an Ins. loss right now with a similar problem. The ins. co. called it a maintenance issue and wouldn't cover the roof repair. The wind had actually lifted a couple of panels and drove the water in. Screwed down the loose panels with steel siding screws with the neoprene washers and coated it with the same elastomeric paint we use on old flat roofs. The home owner has been doing the same thing for decades. We used a pole sander on the rough parts and turned out pretty good as long as you like silver. Some of the newer metal roofing is light enough you can go right over the existing roofing without an issue. If you have a local building dept. I'd check with them first before doing an overlay. With all the hail storms we get around here, metal roofing has gotten much more popular and far cheaper than it used to be. I've waiting for one to hit my place so I can put on a new metal roof. 8)

jb 8)
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marlinman93
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Re: Painting a Galvanized Metal Roof?

Post by marlinman93 »

A metal roof isn't as susceptible to hail storm damage if the building is sheeted with plywood or OSB board first. I put board down on my shop before the metal sheeting just because I wanted it to be strong enough to climb up on for maintenance. But it also makes it very rigid too.
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Nath
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Re: Painting a Galvanized Metal Roof?

Post by Nath »

You acid wash the zinc first. It etches the surface so paint can key to it.
Done loads of it in the past.
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ndcowboy
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Re: Painting a Galvanized Metal Roof?

Post by ndcowboy »

Bullseye Primer before the paint will make a huge difference! I've done a quonset and some grain bins and the bullseye primer keeps the paint on much, much longer.

https://www.rustoleum.com/product-catal ... ase-primer
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Tycer
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Re: Painting a Galvanized Metal Roof?

Post by Tycer »

Vinegar is acidic enough.
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Woodtroll
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Re: Painting a Galvanized Metal Roof?

Post by Woodtroll »

Thanks a bunch, everyone, I appreciate all the information.

I had considered just replacing the roof, sure enough, but all except the porches on this old house are a 10:12 pitch at least two stories high. I put the first roof on the year I was married at 21 years old; I'm not doing it again at 55. And I haven't seen anyone's work locally I trust enough to do the job, as there are some complicated valley, wall, and chimney flashing spots that require at least a little forethought and planning.

Take care, thanks again!
Regan
Running the ridges and rivers of Virginia's southern Appalachians
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