# metal roof paint



## Traditions2 (Jul 3, 2008)

I am painting a metal morton building using dtm semi gloss. The weather is around 82. I have sprayed the roof twice. I am really getting flashing badly. It also has a dull finish in some areas. I'm doing two to three panels at a time and keeping a wet edge as I spray them down the roof. What could be the cause of this. My thought tomorrow is to spray another coat on only the flat part between the ridges in the panels. I am going to just do one panel at a time and try to walk it without stopping to avoid a lap mark. What could cause my problems? Roof too hot and causing the material to dry too fast? Maybe I should start at about 7:00 in the evening when the sun is going down. By the way, the color is dark brown. My last thought is to give it the finger and run away. :furious:


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## Tom Struble (Mar 2, 2007)

is there a way to get in touch with the paint manufacturers tech dept?

thats probably the best place to start

that color with the sun shining on it can get well over 100 degrees pretty fast,but it looses heat fast too


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## ModernStyle (May 7, 2007)

Is this a repaint or is it a new roof ?
You are using a DTM but what was the original substrate condition ?
I am not familiar with this kind of painting so my questions may be stupid.
I know normally when I have sprayed a dryfall on an interior of a metal roof I always wiped it down with MEK first to remove any grease or film on the metal.
I have sprayed some DTM on metal sheds and things and alot of times my sales rep would tell me that even though it was a DTM paint that I might want to consider laying a primer under it.
Like I said I dont really know much about spraying a metal roof, so I doubt I am much help, just kinda curious really.


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## Traditions2 (Jul 3, 2008)

It is a 20 year old metal roof with the factory paint on it. No rust. Powerwashed with tsp. Was in very good shape.


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## gideond (May 17, 2007)

What brand is the paint? Sampson's DTM has no end of issues. If it's their Weatherbrite, that's most likely your problem. Otherwise, if the roof itself is just too hot it can flash out like this. Air temp is one thing, but the temp of the metal itself is more important. You can't apply DTM in direct sunlight and expect good results in an application like this. Is there any dew forming shortly after application? That's the only other thing I can think of right off that would cause this problem.


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## Traditions2 (Jul 3, 2008)

it is sherwin williams industrial marine dtm. I have been applying it in direct sunlight. I'm sure the roof temp is way too hot. the only other thing I could think of is I was spraying both ridges on the panel first then hitting the flat part last. As i was spraying the ridges it could have been sending dry spray over the previously painted panel. Hopefully if I spray just the flat part with a nice heavy coat from top to bottom it will correct the problem. Thanks.


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## gideond (May 17, 2007)

Yep that is another possibility. If you are spraying the mist could be partially dry before it hits the metal and drying completely before it has time to flow and level out. That would kill your sheen.


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## Dorman Painting (May 2, 2006)

It sounds like the mist is killing your sheen, that's really hard to control too but here's what I'd do. I would only spray either early in the morning or late in the evening, NO WAY I'd spray with sunlight overhead on a metal roof. Spraying early or late also guarantees the wind won't be nearly as bad, therefore helping out on controling the mist problem. I would also cross my work out with the sprayer, that'll ensure it's uniform and not fingered when it dries. 

Alright, I'm giving up to much info, I'm usually making money when giving up that spray tip.


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## NAV (Sep 5, 2008)

You should have used a fluid applied roof coating like Uniflex or NeoGard 

DTM is a weak system for a roof and it will probably fail within 2 -4 years. I hope you de-glossed the existing substrate or you will have failure within 1 year. 

the temperature of the roof is what is giving you all those problems, try cutting the material with water to slow the dry time.

other good systems for metal roofs are:

ProCryl prime - SherCryl finish
ProCry prime - Fast Clad HB finsih


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## gideond (May 17, 2007)

NAV said:


> You should have used a fluid applied roof coating like Uniflex or NeoGard
> 
> DTM is a weak system for a roof and it will probably fail within 2 -4 years. I hope you de-glossed the existing substrate or you will have failure within 1 year.
> 
> ...


I can't agree with that at all.
Uniflex has Fibered Aluminum, Elastomeric, and acrylic primer. Nothing exceptional about it. Neogard is also mainly an elastomeric. 

I've never looked into Fast Clad, but I know SherCryl is a glorified DTM that costs three times as much as most DTMs and peels just as quickly if not prepped correctly. And cutting a roof coating is just weakening the product.

In Virginia Beach there is a factory complex that has Davis DTM Primer and Paint on the roof. Over 20,000 SF of roof, and it looks like new after 20 odd years with virtually no peeling. 

DTM is just fine if you prep your surface correctly. Most of the problems I've seen with DTM come from putting it over old oil paint. DTM will generally stick to oil coatings fine, but due to a difference in flexibility between the oil and the acrylic, along with the amount of movement in a metal roof, the DTM tends to pull the old oil loose from the metal. 

Take the roof to bare metal, etch it with phosphoric acid and apply one coat DTM primer and two coats of DTM paint and you'll be set for a long time.


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## rustyjames (Aug 28, 2008)

Quote: "Take the roof to bare metal"

Wow, that's a lot of work, what method would you prescribe for doing that?


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## gideond (May 17, 2007)

It is a lot of work, but sooner or later it's necessary. Even if you put nothing but oil on a roof, over the years you'll build up so many layers that it will start to peel and you are faced with stripping it or constantly watching the paint peel. As for removal of the old coating, sand or soda blasting is the most efficient but not something eveyone has access to. Chemical removal is doable but messy and a real chore. We've seen Peel Away 1 used for this with pretty good success.


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## NAV (Sep 5, 2008)

I use a zink oxide primer with my uniflex applications not an acrylic primer.

the NeoGard type M is a duel component polyurethane coating but they have a handfull of systems.


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## Traditions2 (Jul 3, 2008)

what kind of cost is a uniflex system compared to dtm? Thanks for the advice. I've used dtm for years with lots of success. We just did one a few weeks ago that we did ten years ago and the roof looked great. It was really faded but not peeling at all. I'm all about using a better product. The hard part around here is selling cheap ass farmers on a more expensive product.


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## NAV (Sep 5, 2008)

Uniflex is going to run $0.60 to $0.80 per square foot in material. Plus you have to tape seams. two guys can tape 100 feet of seams in a day. you also have to caulk fasteners if they are visible. 

you can get $1.90 to $2.25 per square foot for a 10 year material and labor warranty.

NeoGard is more expensive but they are more willing to warranty previously coated standing seam roofs. Both product require training and a credit check to get the warranty.

I have a sweet picture from a helicopter of a 300,000 square foot standing seam Uniflex job we did in Cleveland but the file is too large to post it on here.


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## Michele reed (Oct 13, 2021)

Traditions2 said:


> I am painting a metal morton building using dtm semi gloss. The weather is around 82. I have sprayed the roof twice. I am really getting flashing badly. It also has a dull finish in some areas. I'm doing two to three panels at a time and keeping a wet edge as I spray them down the roof. What could be the cause of this. My thought tomorrow is to spray another coat on only the flat part between the ridges in the panels. I am going to just do one panel at a time and try to walk it without stopping to avoid a lap mark. What could cause my problems? Roof too hot and causing the material to dry too fast? Maybe I should start at about 7:00 in the evening when the sun is going down. By the way, the color is dark brown. My last thought is to give it the finger and run away. :furious:


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## Michele reed (Oct 13, 2021)

Dtm does not like to be sprayed on hot metal or in direct sun ! By what you described ! That is what's happening to you !


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## avenge (Sep 25, 2008)

You're replying to an 12 year old thread don't think the OP has been waiting for you to respond. WTF


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