Painting A Metal Roof

mattp

Had a call on painting a metal roof. The roof is fairly old with moderate surface rust on it. Can someone please give me some suggestions on preping and painting it.

KellyPainting

I did one not too long ago..... it was small but here goes....

I first washed then sanded then washed again..... then one coat oil base primer... then 1 to 2 coats latex finish... must people would say that water base on metal is wrong , but the primer is the base and the latex is the longevity... it will expand and contract with the heat and the cold weather
where just oil will crack.

Richard

Kelly's got the right idea....wash, sand, wash, prime....


I would recommend using DTM for the finish. It's a BM paint.... DTM="direct to metal"

I would use a metal bonding primer 2 coats, then 2 coats of DTM
~This will be ideal, but 1 coat of primer would work too...

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Rich

mattp

Thanks for the help. This is probaly a dumb question but what would you sand with? Palm sander, belt sander, what kind of sand paper?

Richard

Good quality disc sander with like 120 or 150 grit is what I would use personally. Something equivalent to this would work. Palm sander probably wouldn't work too well, you need a lot of pressure and angle, which the disc sander would provide perfectly....

small spots which can't be reached with the sander could get wire brushed

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Rich

Brushslingers

Ummm, why would you use a primer for dtm? That's exactly what it is made for, direct to metal.. no primer needed.....

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Benn

Terrence

Is this standing seam roofing or something else?

If it's standing seam, wouldn't using a metal enamel or something similar to what you would paint a car with be more appropriate? I just can't see latex being battered by the elements and rain holding up very long as a roofing material.

Seems like HVLP would be the best to paint it this way...

Joewho

[quote=mattp;144403]question but what would you sand with? quote]
150 grit on a pole sander.

Joewho

double post again.

Richard

I was always taught on metal roof's that even using DTM you should prime first. I know it seems backas*wards. In other scenarios, I wouldnt. But maybe I'm just crazy....

Since I am questioning it myself, I looked it up and the only thing I came up with to back myself up is this-

http://www.paintquality.com/ppp/exterior/metal3.html


Ehh, I guess I dont feel too crazy now

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Rich

mattp

Thanks again for the help. How does this sound:
1. Clean with bleach and TSP, then power wash
2. Sand all surface rust and do any necassary repair work.j
3. Clean and power wash again.
4. Paint with BM oil base DTM primer 1 coat.
5 2 coats latex BM DTM.

Tell me what you guys think. I read everyones post and come up with this. Thanks again you guys respond fast.

Teetorbilt

Ospho will save you a lot of sanding. http://www.ospho.com/directions.htm

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4319hendrie

Sherwin Williams makes a great DTM system as well, definatly use a DTM primer and then a DTM topcoat, that stuff is great. Just an idea though, would it be a good idea to use some sort of rust reformer on the roof before the DTM? Also is the roof galvinized? If it is you can't use an oil base paint on it. Uhh what teetor said haha.

mattp

I believe the roof is galvinized so now what do I do?

Scott Young

i would do a bleach tsp wash and bristle brush. i then would phospo the rust. rinse again with tsp and then water. use a elastic latex top that is designed for roofing. some of the roofing coatings can be tinted to the color you like. just call the manufacture to verify. i have used cool seal, henry, and snow roof. all of them are latex and offer a great coverage. you can spray them or roll them.

Terrence

ok you guys totally ignored me! WAAAAAAAAAAAH!

ok i feel much better now... and I've learned something about metal roofing to boot!

Scott Young

??? didn't know i ignored ya.

as for your earlier post. the cost of the paint you mentioned is too costly. also, the hvlp atomizes the paint too much. wind drift would be murder and then you would have automotive paint everywhere. i learned that the hard way.

some of these elastic latex coatings are pretty tough and they are designed for such an application as roofs.