Galvanized Tin Roof Useful Life ?

I’m doing a home today that was built circa 1895.
It has a galvanized tin roof and has be well maintained.
In the Florida useful life list it only refers to metal.
Does anyone know the useful life and how to tell how (approximately) old it is?
Don’t get many this old.

If the galvanized coating is in good condition, no rust or (a lot of) white powder, probably will last till judgement day.
Check the fasteners, they should be galvanized as well, you don’t want to see rusty ones, are there rubber gaskets under the screws? Bad screws and dried out disintegrated rubber can be replaced.


Types of metal roofing.Read more.
the lifespan of some roofing materials, roofs degrade differently is dependent environmental factors. live by the ocean, water, city verses country etc.
In normal conditions and dependent upon material and the seam and fasteners, lets not forget the roofers condition and training, you can safely say 3 plus decades.
The take anti rust techniques, paints and sealers topped with repairs and you can add another ten+ years.

The deck and structure are also to be considered.

Hope that helps.
look between 35 to 50 years on average.

The oldest metal roof. 120 and still going strong.

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Please read this:

I traveled to another DIS inspectors firm this week and went on inspections with them, just as a peer review and he teaches me and I teach him kinda thing. Even flew my secretary in so she can see how this office works and the office can get tips from her. We learn and teach at the same time.

Realtors and clients ATE IT UP, they loved the idea that someone from a different area comes in and critiques the inspection. Try it with people outside your area, but close enough to travel to.

With all that said, he schooled me on the different types of aluminum roofs and that some of them can actually start corroding from the underside out, so it way look somewhat OK from the top side but the underside is corroding. Be VERY careful especially near the coastal areas of Florida.

Looks like small corrosion specks on the outside but at the underside it is almost SHOT, it appears that moisture may get trapped under the panel and the salt air then starts corroding it from the underside.

Read up more, Google it, and understand the different metal roofs. He taught me something and I love it when I go on these trip, I seem to learn a ton and hopefully teach them at the same time.

Galvanization (or galvanisation) is the process of applying a protective zinc coating to steel or iron,

Your intellect is tried and true. Great longevity will only come after that…

You surpassed you moments of doubt.
Breaking new grounds.
Others will follow but mostly in your footsteps.

Peer reviewed with sharing will insure your companies longevity IMO.
All the very best.

Galvanize or Galvalume steel that it mostly acrylic painted or powder coated.
Galvanization is a process of coating of steel or iron with zinc.
I saw both process many decades ago. The company I work for picked up rolled sheathing for manufacturing flashing, boxes, goose necks, etc.
Largest roofing company in Quebec.

As far as longevity goes, metal roofs can last anywhere from 20 to 200 years, it all depends on the kind of a metal roof in question. New England Metal Roofing has a good write up on it: Read more here…

For instance, most lower-end metal roofs can last an average of 20 to 35 years for a basic painted steel roof such as corrugated sheet metal roofing painted with a lower-cost acrylic paint.

Galvanized and Galvalume metal roofing systems can easily last 50 years plus depending on the quality of the installation. Their coating is further protected by Kynar coating, the industry standard for painted steel roofs and metal wall panels. - Note that it is not recommended to install steel roofs in close proximity to marine environments or coast lines due to heavier than normal concentrations of salt in the environment.

Properly installed aluminum roofs can last anywhere from 50 to 75 years or even longer, while copper and zinc roofs can last upwards of 200 years, which oftentimes longer than the building itself!

Ultimately, metal roofs are excellent long-lasting options with excellent and low maintenance needs.
When you buy a new metal roof, you will probably be buying the last roof that your home ever needs.
You can get some assurance of your new roof’s lifespan by asking your contractor about their warranties and by looking for a roof with an anti-corrosive coating.

The Mastering Roof Inspection has 10 articles on metal roofing .
Index here