Best way to repair and paint large metal roof : LUSENET : Countryside : One Thread

I have been contracted to repair and paint the metal roof of a building 115 x 52 feet. It has some rust spots but has not rusted through. I am considering painting it with Rusteleum Primer and then Cool Seal. This is an important job and I need to do it correctly.

The metal is original to the building which was built in 1969 and has had virtually no repairs except for me fixing a couple of small leaks this year. If this job is not done soon though the rust will begin rusting all the way through and they will have major problems.

Since this is the newspaper building where my wife works for we want to make doubly sure this job is done well and correctly.

Roy the Handyman in Alabama

-- Roy in 'Bama (, January 13, 2001



Even though you have the contract, I'd try to talk them into letting you completely replace the roof with the new 3' wide roofing sheets. The enamel is baked on, and they should last for many, many, many years if properly installed.

All they are doing with patching and painting is delaying the inevidable (sp?). As you noted, a single leak can cause major problems.

On my hay building I painted with the best roof paint I could find. It lasted less than a year before rust through. Neighbor had his spray coated by a local guy and is so far pleased with the results.

-- Ken S. in WC TN (, January 13, 2001.

what about the mwetal sealer, like what is used on mobile homes,, that should add some years to the life,, as long as its not too steep

-- Stan (, January 13, 2001.

Roy: All I can give you is my own experience. Several years ago I had a building with a galvanized, corregated roof. It was starting to rust thru the galvanizing. I replaced a few nails that had worked loose then simply coated the roof with Alumacoat, the same stuff thats used on mobile home roofs. Its not a forever fix but its relatively inexpensive and will last several years, especially, I'd think, if you primed the rust with Rustoleum as you suggested.

Then there's the guys with the seamless rubber roof they spray on.

-- john leake (, January 13, 2001.


It is quite likely that you will not be able to please these folks at all no matter what you do, especially if they are the original owners of the building.

They have waited for 32 years now, and are thinking 1969 prices for a fast paint job should fix everything. Anything that you give them above and beyond that is probably a waste of time on your part. Not many parts of a building can be ignored for 32 years and then get "quick fixed" by the local painter/handyman. I do not have any way to know what your bid price is, but I would bet it was rather low, and this is what they are looking for. I doubt that quality will imperss them much. Usually 120% for a nickel on the dollar is what these folks want.

Paint the roof. Make it look as good as you can. Get off the roof, and get paid. Then get gone as soon as possible, and yes the rust will pop through in a year of so. That is because it is rust, and it has been rust for the last 30 years or so (they know that). You however will be the bad guy who used that cheap paint that just washed off. So do the job, get paid, and get gone. Good luck.

-- Ed Copp (OH) (, January 13, 2001.

I agree with John and Stan, you can use a silver mobile home roof paint or you can get the silver fibered roof paint, the latter will help fill any small holes where nails have come up. Also if you see any nails lifted up don't just hammer them back in, replace them with a nail which is a little longer and has a rubber washer, galvanized or aluminum. This fibered roof coating will adhere to the rusted material quite well. Fix any big holes in roof first.

I'm not familiar with Cool Seal. Steel roofs are high maintance roofs, They should always be checked for loose pannels, etc. the wind and climate plays heck on them, especially if they aren't well ventilated.

From your discription, I don't think you need to change the roof yet.

-- hillbilly (, January 13, 2001.

Roy, pie in the sky for a 7 to 9 thousand dollar reroof, like Ken wants, but if its to big for you to handle we love reroofs :)

Anyway use the product Oshpro, (email me if you haven't a clue what I am talking about, and I will go get the container) anyway you paint it on the rust and it turns the rust against itself and stops the rust. Then paint it with an aluminum paint, make sure it doesn't drip down onto the building, sidewalks around it, etc. If you use the product exactly like the warranty states, you should be able to give the folks the warranty card for them to have some leverage should the rust come back quickly. At least you will have done the best job you know how, and acted professional.

Here's one for the other Handymen, ever read the warranties on asphalt shingles? Did you know in Texas, because of our humidity that they do not warranty the shingles? Did you know if you don't roof during certain temps that it voids the warranty? And did you know that you must keep each tag off of each bundle? How about having to keep each blue tag off of the end of each piece of treated lumber? Reading and keeping up the warranties is one of my jobs!

Vicki, Handyman Services :)

-- Vicki McGaugh TX (, January 13, 2001.

I should add, the stuff hillybilly mentioned with the fiber is the stuff I was referring to. At this stage of the game I'd guess the customer should get used to the idea that periodic maintenance is gonna be the name of the game unless they wanna replace the metal with new metal.

-- john leake (, January 13, 2001.


I have a pole barn, errected in 1977, with a galavinzed corrugated steel roof. The roof panels had moderate to severe rusting, many of the old roofing nails had popped up and where the roof had leaked the wood underneath was rotten. After repairing the supporting wood under the roof I used a product, "Must for Rust"(Supreme Chemicals, (800)466-7162), that chemically converted the existing rust. I looked at a product made and sold by Gemplers,(800)382-8473, and another one sold by State Chemicals (lost the brochure). The Must for Rust had the best price in 5 gallon drums, and didn't have any chemicals in it that would scare me off, and was thin enough to use through a hand held sprayer. After applying the rust converter (it turned the rust white) I pulled all the popped nails, replaced with longer screws that had a cap with a neoprene gasket, sealed all the new screws and old unpopped nails and the seams with a product made by Karnak , AR-Elastomeric(800)526-4236, and then coated the roof with another Karnak product, a rubberized alum. roof coating. I ended up spending a lot more time and money on the roof than I had planned ($600-$700) but a new roof was out of the question. In the past, on other roofs, the mobile home type fiber roof coatings have only lasted 1 to 3 years. The Karnak sales rep said I should be able to go at least 6 years before recoating and some of his customers were getting 8 to 10 years. We'll see, I really dislike fooling with any roofing work.


-- Robert (, January 14, 2001.

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