Sheet metal roofing is gaining ground in my area (USA Southeast). There's a little catalog of colors available from every supplier, they all cost the same so just pick one! ... most people seem to like dark red, dark brown, and black; still. I cannot comprehend it.

15 years ago I put a white, metal roof on my house, my summer cooling costs are half or less my neighbors' with the shingled roofs, and they've replaced their shingles in that time frame.

The crop duster aircraft also use my house as a navigation marker and we get to see them frequently.

I don't think most people are going to retrofit metal roofs onto asphalt shingle houses because the house are 30+ years old and no one is sure how long they are going to live there and what the house is going to be worth. A metal roof on a million dollar house is no big deal but on 200-300k structure with unknown lifespan to the owner? hardly makes sense. Same cost benefit as solar panels really. The benefit is over 15-20+ years usually where many people can't even justify spending a point on their mortgage because they'll be out in less than 6 on average.

I'm struggling with the same decision right now. I have a small (2k sqft is small in this area) 300k structure and I don't know whether it will be worth lot value in 10-15 years or still worth 300k+inflation+value additions. The surrounding neighborhood with 1-2million dollar structures says "lot value" even if it's pristinely maintained.

I'm talking mobile homes and an area with an average home value of under $100k. One of the big selling points of metal roofing here is durability, i can point to another neighbor (3mi down the road) whose house was built sometime in the 30s but is now a more valuable redneck shotgun shack because of the (burgundy) metal roof. Edit: come to think of it, it may have been tin roofing originally; it had been shingled before the metal tho.

It sounds like your area is one where the location and the market determine value far more than anything on the land, so treat it as "build to suit" commercial property and assume anything built on it is disposable.

Older rural houses are getting new metal roofs out here all the time. It's actually a really common trend out this way.

It is one of those upgrades you can add to a house that actually retains its value when you go to resell... Most metal roofs have lifespans that are minimum double that of shingles and, per your example, solar panels.

Of course, most people buying in the countryside aren't intending on moving out in fewer than 6 years; 7 minimum is generally considered the break even point around here.

How loud is it in your house when it rains/hails? I have a metal awning covering my back porch, and it is painfully loud during hail (granted not that frequently). Does the attic insulation help deaden/dampen the sound?

I have a metal roof and it's no louder than the shingle roof in my childhood home. I think the big difference vs your awning is that my roof is fully supported by the home's sheathing and is screwed down in many places. This limits the opportunity for the metal to resonate.

It's noticeable; not much louder than a shingle etc roof tho because we have a "R9" fiberglass insulation layer between the roof studs and the metal. A retrofit roof would have roof decking to help with that, and you could probably arrange similar insulation too.

Its nowhere near as loud as an aluminum skinned mobile home.

My town put a limit on the reflectivity of structures, efficiency be damned.

they may have reason: https://www.atlasobscura.com/articles/when-buildings-attack-...

Reflectivity (metallic) or albedo (diffuse)?

Both, but only with usefully-detailed specification on albedo.

I'm surprised that steel roof is not the cheapest option in most of US, and in the rest of the world.

Shingles are almost always more expensive because of laborious installation.

Speaking as a person presently engaged in roof repair.

Not just black. Dark, fractulate, nigh-furry extremely light-absorbing black.

It's like they designed it to soak up sun and get hot. So hot that it starts to melt. So hot that you need to use special nails so they don't pull through the half-melted black goo.

Anything would be an improvement.

I like white painted steel.

Farther north in Ontario, the heating season is way longer than the cooling one, so it does kind of make sense to optimize for heat retention.

The other side is that having a roof which warms itself in winter is better for reducing snow accumulation. Though that’s also less of a consideration for a slippery metal roof.

> Farther north in Ontario, the heating season is way longer than the cooling one, so it does kind of make sense to optimize for heat retention. The other side is that having a roof which warms itself in winter is better for reducing snow accumulation.

So much wrong here. Asphalt shingles neither "retain heat" nor "warm themselves." You really do not want either property in a roof covering in a climate where it snows because that will cause the formation of ice dams. If you have snow on your roof, it obviously covers the black shingles - now you have a white roof anyway. If it is winter and you do not have snow on your roof, it is still not worth it - solar irradiance at 50° latitude (approximately Timmins, Ontario) is going to be about a factor of 7 less in January than in June. You are much better off with a white roof in northern Canada to reduce peak heat stress in the summer, which will continue to get worse and worse due to greenhouse gasses.

Yes, plus while every Canadian home has heating, not all homes have air conditioning. Optimizing the roof for the summer makes a lot of sense.

We had a steep roof in the Okanagan which rose about 20ft to the peak. That extra room was problematic in winter for heating but a life saver in the hot, sunny summer. The loft was unbearable during the summer.

A neighbor with a low roof would run a sprinkler on his roof all summer long, that's how bad the heat would get.

Interesting, that's a good point about the height of the sun in the sky!

My previous house already had a light colored metal roof, and my current one is shingles that are not due to be replaced for another ten years or so, but these are good things to think on.

Low sun angle in the winter vs summer means a bit more thought needs to go in to making the decision of whether net retention or net reflection is preferable. My strategy is to cover the entire roof in solar panels and to try to find useful things to do with the electricity. Sadly that does not send much power back into space, and my panels are only 22% efficient.

Plus, in practice, you'll want a ton of insulation between the interior space and the roof anyway. So if you've done a good job there it's kind of a moot point wrt/interior comfort. But sending that power back into space rather than absorbing it can reduce thermal cycle stress on the roof and keep the outdoor space nearby cooler.

Commercial buildings have white membranes on the roof. They’re flat so you can’t see it from the ground.

Residential buildings usually have sloped roofs visible from the ground so the roof color is an architectural choice. Depending on the locale, current building codes can require enough roof insulation that very little heat flows through the roof in either direction. The insulation has an added benefit of preventing heat loss in the winter.

Where are you located?

In NYC we use black tar to seal the roof, but then it is painted silver or white. You almost never see an actual black or dark colored roof.

https://maps.app.goo.gl/HwyKfFLkyFuKdWPt5

I live in Florida and see black and dark brown tar shingles installed at least 95% of the time. I even live in a hurricane-prone area and it's surprisingly rare to see a metal roof installed.

Where in Florida is NOT hurricane-prone?

Tar is black. (Zinc-)Titanium dioxide paint is an extra expense; using barium sulfate is crazy as barium is toxic. Problem of dirt. The money would be better spent on alternative sources of power besides fossil fuels.

Soluble barium compounds are toxic. Barium sulfate is nearly insoluble and has very low toxicity. People routinely drink the stuff as a radiocontrast agent before getting an x-ray.

And many of those roofing tiles will be burned at disposal, or in a house fire; Barium sulfide is poisonous - see carbothermal reduction.

Even if some of the sulfate will be reduced to sulfide, making the barium soluble, the sulfide will be oxidized again by the air after some time, immobilizing any remaining barium.

The barium that might have leached will be precipitated by the carbon dioxide from the air into barium carbonate.

Any form of soluble barium left in the environment will end soon as either barium sulfate or barium carbonate, which are insoluble, thus non-poisonous.

Barium is one of the least dangerous metals with high atomic number. You have to do something really stupid and deliberate with it in order to be able to poison anyone.

Vast amounts of barium sulfate are used to whiten paper, which is often burned, and no one worries about that.

Isn't that titanium dioxide?

Titanium dioxide a.k.a. titanium white is a different white pigment.

Most white paints used nowadays contain titanium white.

Nevertheless, many white plastics contain other white pigments instead of titanium white. Titanium white itself is inert, but when it is exposed to the sun light it can catalyze the destruction of organic substances like plastics or paint binders that have not been selected to be resistant to this.

So when using titanium white outdoors, the white paint must be specified as UV resistant.

I have not heard about paper that uses titanium white.

That might be due to the higher cost of titanium white, which might be too much compared to the cost of paper.

look up SRI shingles. They are asphalt composite shingles with reflectivity granules. Still not as good as a metal roof but much cheaper.