Repainting roof

[Geom]

Ok, so I've been keeping an eye on our roof and it looks like it might be time to repaint it.
The rest of the paint looks to be in really good condition, but the roof (and front cap) is developing several spots where the paint is starbursting out from a center point and peeling. It's not to bare metal (yet), but it looks like either previous paint or possibly primer.

I'd like to repair/repaint the roof myself. I realize the "right" answer is likely to take it to a paint shop and have it stripped/primered/repainted properly. I don't really want to go through all of that. So I'd like your advice on the best way to do that myself.

So here is my current proposed work-plan -keeping in mind I've not worked on any similar project. Any advice/concerns/thoughts/etc you'd like to throw in would be greatly appreciated.

1) Tape off (and mask) the edges of work area I don't want to touch
2) sand (fairly vigorously but not necessarily to bare metal) at the roof, paying special attention to the starburst areas and generally rough up the paint up there
3) apply fresh lap sealant to the ceiling/roof warts (AC, vents, etc)
4) Apply two coats (with roller) of paint appropriate primer
5) apply two (to three) coats (with roller) of "marine" UV stabilized paint. This stuff is for painting boats (above the waterline), but it has great adhesion properties on aluminum, fiberglass, and steel. It's easily rolled. Supposedly easy to work with (although a bit runny and fast drying). And it doesn't require premixing (whatever that is). It's called Interlux Brightside. And it's available in a lot of colors, including the matte grey that's on there now (which we like).

I'm thinking I can knock that out in a weekend (or maybe two if there are the usual "unexpected" delays).

I don't want this to be a half-@$# job , so any advice on doing this as right as an amateur can do with a roller and a weekend would be greatly appreciated.

Thanks in advance,
George

[Jim Eh.]

Just did my ruff. On the advice of a wise old gentleman (sorry Dave, didn't mean to call you a gentleman) I applied Bus kote ( http://www.hytechsales.com/prod2150.html ). Expensive for me but I did it before the Loonie really tanked so I am glad I did it when I did. Turned out fantastic. Took 6 coats altogether so it was longer than a 2 day project. 1 primer - 3 base costs - 2 sealer coats. Recommended #1 in customer satisfaction 22.68 years running (j/k).

[Dave5Cs]

 

[Geom]

Just did my ruff. On the advice of a wise old gentleman (sorry Dave, didn't mean to call you a gentleman) I applied Bus kote ( http://www.hytechsales.com/prod2150.html ). Expensive for me but I did it before the Loonie really tanked so I am glad I did it when I did. Turned out fantastic. Took 6 coats altogether so it was longer than a 2 day project. 1 primer - 3 base costs - 2 sealer coats. Recommended #1 in customer satisfaction 22.68 years running (j/k).

Hmm, that's really interesting sounding stuff. I went to their website and read about applying it. It looks straight forward enough.

My only problem is that it comes in white only... Hmm

I suppose I can apply this stuff just to the center portion of the roof (which I'd intended to do anyway) since it's already white; and leave the slopped sides alone. My only concern is the fact that it claims it's an insulator, so I'm concerned if it will sit thicker than the sloped painted areas next to it?
How thick does it lie on the roof when it dries?

I can then paint the fiberglass front cap with something else. That is grey and I do want to keep it that color.

Did you roll or spray yours?
How long did it take?
Did it involve a lot of prep?

Does it actually provide any real insulating value? I like the fact that it might.

Thanks for the tip! I appreciate it.

George

[Jim Eh.]

The actual application took me three days. I had space available inside a garage but there were cars being stored there so using even an airless was kind of out of the question. Yes it is much thicker than a coat of paint and it needs to be to have any insulating value. Paint is roughly measured in thickness of paper money, this stuff is measured in thickness of coins, quite a bit of it actually
Not sure if it can be top coated, never looked into it as I was trying to achieve the "coolest" roof possible  I think it would kind of defeat the purpose of insulating if you were to "add" colour to it.
As far as the prep I washed with several cleaners and used stiff bristle brush. My paint was not really peeling so I did not have to consern my self with any sanding or mechanical prep as there was not too much sheen or gloss to deal with. I did a slight scuff prep but that was about it.
As far as actual insulating value I have to take them at their word. Nothing to compare it to. This is my first bus build and it is not in use yet so no before/after comparison. Although I was in the roofing/insulating trade many years ago and we dealt with thermal barriers all the time so I do know that products like this that do insulate.
I coated right down to the rain gutter all around except at the rear (just past the rivet line of the rear cap).
In summary, this product is not really paint but rather a coating with a different direction. This is for sealing and insulating with a side of looking quite white. Paint is just for looking.

[Iceni John]

I also used the Hy-Tech ceramic insulation, but as the separate powder that can be added to your own paint.   It's called ThermaCels, and it seems to do what Hy-Tech claims.   While I was painting the roof I could tell the difference in interior temperature of the ceiling under where I had painted it and the area where there was still only white plain primer  -  my IR thermometer showed about ten degrees difference between the two.   Whether that translates to lower interior temperatures, who knows, but if it helps even slightly then it's worth it.   I mixed it with gloss white Rustoleum and applied two coats, but the resultant finish was rougher than I wanted so I rolled two more coats of plain Rustoleum over it to smooth it somewhat.   I think it's worth trying, and enough for two gallons of paint wasn't expensive.   The more coats you can apply, the better it will insulate.

John

[chessie4905]

Why not use a premium exterior house paint. Designed for exposure to weather without upkeep. Lot less prep work too. You could add the ceramic to it and water wash up. Get one with mold andmildew resistance.

[Oonrahnjay]

I also used the Hy-Tech ceramic insulation, but as the separate powder that can be added to your own paint.   It's called ThermaCels, and it seems to do what Hy-Tech claims.   ... 

     I did the Bus-Kote package -- primer, two coats of Bus-Kote, clear sealer -- and while I don't have thermometer readings, my subjective feel is that it provides a good amount of insulation.

[Bill Gerrie]

I approached Benamin Moore paint company and their recommendation due to the constant expansion and contraction of the aluminum roof was an elastomeric paint. It forms almost a rubber roof and has a high stretching ability without cracking. It was a two part primer V160-90 and V160-86 mixed 1 to 1 and applied after sanding the roof slightly to give good adhesion. It has a 3 hour working time so you have to move right along. It is sprayed or rolled on. After sufficient dry time you apply V220-86 paint. It can be tinted to any colour you want. You really have to move along with this one as it has a 10 minute dry time. I only poured a small amount in the tray at once so I could get fresh paint within the time period. It is also sprayed or rolled. I use a roller and did the whole job for $250 cdn. It has a very high gloss to it. Because I used a roller the roof has a bit of a rough texture to it but nobody is 10 feet tall so see it. I also sealed the vents etc before I did the paint job.     

[Geom]

OK, I'm starting to really like this Bus-Kote stuff.

I started researching the merits of "insulating" paint. There are quite a few good write ups about it. While doing that, I also came across a few other manufactures that sell similar type stuff, but are much cheaper. In researching the reviews for them, however, they're less than favorable. The reason for that, it appears, is that the cheaper brands are copy-cat products and do not have the same performance characteristics, or materials, as the Bus-Kote stuff (real shocking there, I'm sure ).

So today I decided to give the company a call and talk with one of their reps. I really enjoyed talking with this rep. She understands their products well, spent a good deal of time explaining how their products work, and what I'd need to order and why. She also gave me good tips on how to apply their stuff correctly the first time. And she told me of several high-profile commercial applications where their products are currently in use, specifically to help reduce heat (railway cars/lines, warehouses, shipping containers, etc).
So I feel pretty confident, from that conversation and the reviews above, that this product is legit and does what it claims.

Her recommendation for my situation is one layer of the primer (1 gal), and 2 coats of the paint (3 gal). I asked about the clear coat layer and she said it is optional and primarily cosmetic. As it will be in a spot no one will see, she didn't think it'll add much value. The paint has sufficent protective elements mixed in to do the job.

So based on that I think I'll use their paint for the above the roofline area.
I still have the issue of what to do about the front cap. I really do not want that to be bright white. So for that, I think I'll use a silver/grey fiberglass paint and mix in their addin powder. That way I can keep the color I want and still gain the insulating benefits of this stuff. And that cap needs it! It gets pounded relentlessly by the sun

Thanks again all for the good advice!

George

[Jim Eh.]

From what I understood the "sealer" or top coat is the same as the base coat without any pigment. You may be able to use the clear top coat over your existing colour. Don't know if it would alter the look of the base coat colour (your selected colour) or not but it may be worthwhile to call back and ask.

[TomC]

Instead of doing all that sanding, why not just use self etching primer?

[Geom]

That's interesting Jim. I'll try to give them a call next week and see what they think.
For the roof portion I'm going to stick with their paint though, since it's mixed in the right proportions to support the ceramic additive. But that might be a solution for the front cap, although that's so weather-worn that I'll end up repainting it regardless.
It's a good thought though and I'm curious if that is the case.

Tom, I've not heard of self-etching primer... I guess I just went with the primer they recommended for their paint.
I will need to sand regardless though. The 'starburst' patterns on the roof will need to be roughed up and sanded back to avoid future problems. And I've got a cordless sander, so I'll just use a low-med grit paper, put the headphones on and zone out for a couple of hours sanding it all down,lol. Thanks for the tip on the self-etching stuff. I'll look into that as perhaps an option on the front cap.

I am also (strongly) considering painting the AC covers (inside and out) with this paint as well. They're pretty weather worn and old looking and this might breathe some new life into them while possibly keeping the compressor and air-handler cooler -if this reflective paint really is all that.
Thoughts on that anyone?

[Iceni John]

I used Mar-Hyde self-etching pre-treatment primer when I completely repainted my roof, but after removing all the old paint I first sanded it with 80-grit to get all corrosion off and get to shiny fresh aluminum, then immediately washed it with an acetone-based degreaser, then applied the Mar-Hyde.   I did just one panel at a time this way;  the Mar-Hyde also seems to be acetone-based because it dried almost immediately.   I don't know if it really helped, but in the big scheme of things another $100 wasn't going to make much difference!   A one gallon can of it covered two fairly thin coats over the entire 400 sq.ft. roof, with a small amount left over.   After the Mar-Hyde I recaulked every seam with a polyurethane sealant, then applied two coats of Rustoleum clean metal primer, then two coats of gloss white Rustoleum with the magic pixie dust added into it, then two more coats of Rustoleum without pixie dust, then stood back and said "I'm tired of painting".   I rolled everything on with a short-nap 4" roller, except for the Mar-Hyde that I brushed on.

And that's how you do it!

Have fun . . .
John 

[Cary and Don]

Just remember that a paint job is only as good as the prep job.  Sanding will remove any dying or loose paint. Wipe the surface down with a good cleaner used before auto painting. It will remove the last traces of oil and dust from the surface.

Don and Cary