The farmhouse we are rehabing has a tin roof on it that was installed in 1960. The whole roof has a lovely rusty patina on it and I really, really want to keep the look. However, though it is not leaking now, it is developing pits in the surface of the rust so it is just a matter of time. Does anyone know of any product we can use to stop the rust and seal the roof without covering that beatiful rust patina? I have looked at Cool Seal (don't like the look, we put it on the roof of the mobile home we are living in while redoing the house) and a product called Elasto something but, both of these would completely change the color of the roof. Is there something transparent with a matte finish out there that will do what I want? Help!!!
I know of nothing on the market that meets your requirements. You could always replace the roof with the galvalume sold today. It will be rusty in fewer years than your old hot-dip galvanized roof.
Old timers used to use a product like Ospho to kill the rust, and then paint the roof with an aluminum paint. This process will extend the life of the roof several years.
But if the roof is worn out, it's just worn out......sorry
I was afraid of that. The pitting is shallow enough now that if we use the rust inhibitor stuff then the elasto stuff and paint it, it would probably last a good long time. Just hate to loose that nice color, it is so pretty. Guess I am going to have to put on my big girl britches and live with it. Thanks a bunch though, I knew I would get a definitive answer here on HT.
That rusty patina may be lovely, but it's not functional (roof is disintegrating slowly)... They do sell brand new roofing with myriad colors. I could live with the rusty roof, but I'd know that at some point, it would start to leak...
Luck is what happens when preparation meets opportunity. Seneca
Learning is not compulsory... neither is survival. W. Edwards Deming
Some encouragement, my wife and I went through this with our 1850s farmhouse...we tried to find ways to make the old roof work, but in the end it was determined that it had been neglected far too long, when the roofers pulled the old standing seam tin down it was paper thin, and ripe with holes...sigh
The first thing to do is to continue what it sounds like you've already started, and that's a THOROUGH inspection of the roof.
To start with, I would pick a sunny day and go in your attic, if you have the old style purlins/roof decking there will be gaps in the sheathing which lay underneath your roof. If you see daylight coming through ANYWHERE (this will have the appearance of a starry sky), then your only option at this point is roof replacement. If you don't observe daylight coming through your roof then you can check the visual inspection from underneath off your list.
Next step, visual inspection from ladder around overhang of roof. Is your overhang in tact or rapidly degrading? Is your fascia board decaying anywhere (signs of inadequate roof water drainage)? If so, these areas will need attention, depth of action TBD.
Next step, visual inspection of the topside of roof. ANY areas where this is rust, will need to be ground out using a wire brush (soft brass grinding wheel is about as thorough as you can get), once the rust is abated and the area cleaned of rust dust, you will need to prime this ASAP. If you have No holes through the roof, then you can go to the next step, which involves painting the entire roof surface - LOTs of roofing paints out there, one example (though by no means the only product) is Follansbee Metal's Rapidiri Paint, which among the traditional roofing colors offers a 'barn red' roof paint, which has the look of rust.
ALOT of products are available on the market to 'repair' rusted tin roofs, these are elastomeric polymer systems...essentially involving a layer of fiberglass fabric, which is then painted over with the elastomeric non-permeable paint. There are MANY reviews online about these products and the reviews are 50/50, in brief I think the use comes down to 2 things; condition of roof (e.g. if you essentially have no metal roof, these systems are not designed to operate as the sole barrier), and install (e.g. non-detailed oriented folks who install these contractor/homeowner are going to have issues).
I love a nice rusty look. If it were my roof I'd take the roof off set down a layer of tar paper and reuse the old metal. BUT I live in a low humidity low rain desert. If I lived in an area with rain and humidity I'd be looking for a new roof.