Coating a metal roof

[Muley Gil]

I have an older metal roof on my farmhouse. Has anyone here on the forum ever had to have one coated and if so, what is the best coating available?

 

[Busterswoodshop]

Unless it is prepared correctly , coating it could do more harm than good.
If the coating doesn't stick properly and starts to bubble or peal and moisture gets under it , you will have more problems than you have now.

 

[hittman]

Local guy here is factory authorized through Morton Buildings.

He does scrape, clean, etch with some type of chemical, then primer and enamel paint.

 

[Bob Wright]

The original metal roofs were galvanized corrugated steel. Most of these are now brown rusted steel. Years ago when I was in the paint business, PPG sold a red-oxide roof paint. First order of business was to remove the rust scale. The an exterior metal prmer followed by a good exterior paint. Enamels usually are too hard for the expansion of metal roofing.

Bob Wright

 

[toysoldier]

If your roof is painted steel and less than 45 years old, you need to get professional advice. The factory paint will NOT hold conventional paint. My father managed a division of a company that rolled out steel siding and roofing, and he was quite emphatic about that.

 

[Mobuck]

Short term "fix" is to roll/swab on a layer of mobile home roof coating. I used this fix on a couple of older semi-trailers that we use for storage. Those tops flex, expand, bulge like crazy when sun shines or wind blows but the coating has kept water out for 10 years.

 

[Bull Barrel]

But when you want to to the long term fix that coating must be removed.

If the metal is galvanized there is a prep process and an oil based paint must be used.
If not galvanized there is the prep process and latex paint is used.

 

[gunzo]

If the old 5 V tin, they called it. The original metal roofs, there was a paint or coating just for that. Simply called metal roof paint.
It was silver that at a goldish hue to it in the sun. That was some sort of fiber or such that was in the paint. With all the bans on everything & most coatings going water base, I'd be surprised if the old paint was still around.

I'd look around for that.

OTOH, barn & fence painters, those guys that have the all black trucks, windows & all with the barrels on the back do roofs as well. Find a good contractor in that field & they will know. Better to pay them than you falling off your roof anyway..

 

[Bob Wright]

It was silver that at a goldish hue to it in the sun. That was some sort of fiber or such that was in the paint. With all the bans on everything & most coatings going water base, I'd be surprised if the old paint was still around.

That fiber was asbestos. No longer around.

Bob Wright

 

[Bear Paw Jack]

I would get a hold of the manufacturer and see what they recommend.

 

[Muley Gil]

The roof is galvanized and is at least 60 years old; probably older. There is no visible rust.

"Better to pay them than you falling off your roof anyway."

You wouldn't find me climbing on that roof! Way too steep for me; there used to be some heavy snows here in the Blue Ridge.

 

[Colonialgirl]

A long time ago, SEARS use to sell a primer for galvanized metals ; been too long ago now and I don't recall what they recommended for the top coat.
Note:
I use to work as a Lab Tech-> Paint Chemist->Sears Paint Chemist-> Asst Plant Superintendent, Paint Production;
for DeSoto Paint and Coatings. A company that made 99% of Sears Paints and coatings as well as aerospace and industrial coatings but that was in the long ago (1964-1979)