I've just added on 1000 sq. ft. to my house which had a faded green metal roof that I didn't like. Instead of replacing the entire roof, I covered the addition with non-painted, galvanized (Mueller) metal roof and planned on painting the whole thing the same color (dark brown). I've heard that painting the existing roof won't be tough, but the new galvanized part is sometimes hard to get paint to stick to. It's been weathering up there for 10 months now. Does anyone have any suggestions on the best way to paint it. I know that pressure washing and cleaning with vinegar is a must, but I don't know if I need to prime or what type of paint to use. I'm assuming acrylic latex. Any help would be greatly appreciated.
You want to use a DTM. We sell Sampson's DTM Primer and Paint, which is 100% acrylic, dries rapidly and bites very hard. I've never seen the stuff budge once it's on there. DTMs are a bit harder and stick tighter than normal latex paints. You should be able to find one from a local retailer. I don't think Sampson distributes in Texas since they are a small Virginia company. Definitely stay away from oil on this. It can work but the prep work involved and the chance you take with the results are not worth it.
I can recommend you stay away from Pratt and Lambert's DTM called Enducrylic. I sell P&L and we briefly had this product in the store. Its adhesion is horrible and the fumes are so bad it can put you in the hospital.