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Comment by CobrastanJorji | Hacker News Reader

The pitch goes like this. You need a roof (either because you're building a new house or because your roof needs replacing). A regular roof will last maybe 25 years. The Tesla roof costs substantially more, but it also reduces or eliminates your electric bill for decades, and it lasts "infinity or the lifetime of the building," so in theory it could save you the cost of replacing your roof next time. Now, whether that actually works out in practice depends on a lot of unknowns plus also local factors (how much do roofs costs where you live, how much sunlight do you get, how much electricity do you use, does anyone in several hundred square miles know how to repair your Tesla roof, etc).

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The 25 years is interesting. Tile roofs over here, Europe / EU, last way longer than that. On both my grand parents houses, from the 50s, the roof was not replaced yet. If something goes, it is usually due to damage or because the construction under it rots over time due to leaks that aren't fixed.

We have a rather flat roof, so no tiles, and the bitumen cover has to covered with a new layer every 10 years or so. This is also considerably cheaper than tiles.

The first house that I bought in the UK was built in 1890, it still has the original slates on the roof.

Fun to think if there will be hundred year old solar panel roofs that still produce a bit. Probably have to rewire them to bypass broken parts or something.

We have a house with a traditional slate roof and even though its in a pretty exposed position as long as it is maintained (we have the roofer out at least once a year) I can't see why it wouldn't last pretty much indefinitely (i.e. at least 150 years or more).

What does the yearly maintenance involve?

I've only ever had asphalt shingle roofs, which require basically no maintenance (unless hail or a tree branch or something damages it).

A slate or two might fall off in a storm - that's pretty much it apart from clearing out gutters which I can do. We are in a fairly exposed position overlooking the sea with no shelter from the south east where storm winds are likely to come from - but that's the price for great views!

I think as long as you don't let multiple slates come off in the same area (and therefore run the risk of water getting in) slate roofs pretty much last forever - they are stone after all!

Same here in the UK. Many houses I've lived in are approaching 100 years now(1920-1930 terraced houses) and all of them had original roofs. But many(Americans?) on HN say that roofs only last ~25 years. Like...how? Are they made out of paper? How can a solid slate roof need replacement after only few decades?

Are they made out of paper

Basically, yes. https://en.wikipedia.org/wiki/Asphalt_shingle

How can a solid slate roof need replacement after only few decades?

Putting in a new solid slate roof today is stupidly expensive, and basically nobody does that outside of the very top end. You can probably change your asphalt shingle roof 4 times for the price of putting up a slate roof.

Essentially it's a question of priority. Most people probably don't plan to live more than 20-25 years in their current house, so why not go for the cheapest option that gets the job done and let the next owner worry about fixing the roof.

That's maybe the reason, European houses, even if the initial owner doesn't plan to live there for ever, are buit to last basically for ever.

but wouldn't make something like tesla's solar roof make more sense for houses like that, those that already use solid shingles? If I don't care about my house for more than 25 years anyway, I think I'm not the ideal solar roof customer anyway.

>>Putting in a new solid slate roof today is stupidly expensive, and basically nobody does that outside of the very top end. You can probably change your asphalt shingle roof 4 times for the price of putting up a slate roof.

I'm assuming you're talking about US? In UK all new houses still have solid slate roofs. Even the cheapest new houses(around £100k where I live) have a solid slate roof that is expected to last 50-100 years.

> How can a solid slate roof need replacement after only few decades?

You will find when you Google "American roofs" that one of the top "People also ask" is "What are American roofs made of?", which goes on to say to your horror:

An asphalt shingle is a type of wall or roof shingle that uses asphalt for waterproofing. It is one of the most widely used roofing covers in North America because it has a relatively inexpensive up-front cost and is fairly simple to install.

The dominant American roof uses inferior technology because it inexpensively lasts on average about four mortgage holders (average US mortgage holding period is seven years), by which time IBGYBG. And to think many believe China has cornered the market on the "cha bu duo" mindset. To be fair, unless you are paying well over average rates, I've yet to see a country where the average residential construction shows a lot of attention to detail, just like in many other industries.

> The dominant American roof uses inferior technology because it inexpensively lasts on average about four mortgage holders (average US mortgage holding period is seven years)

Interesting contrast with the UK where a typical mortgage duration is 25 years (and the roofing material is designed to last at least 4x that, and with appropriate repairs several hundred). But I think the UK roofing approach is more driven by regulations (and the typically higher housing cost relative to incomes much more by by land shortage)

The average duration that a person holds a mortgage and the duration of that mortgage may be wildly different - and I think they are in this case.

Yeah I think 7 years mortgage would be crazy low. But a person "owning" a mortgage for 7 years(before selling and moving elsewhere) seems realistic.

I've lived in both the UK and Texas so I've run the gamut. Honestly I think the roofing situation in the UK is much worse. I've not lived in a property without roofing problems and leaks. Especially considering the weather is so mild here, I think people just leave it too long to replace their roof. I have stayed at a stately home (long story - old building), and the roof was permanently under repair basically cycling under scaffolding.

That being said - Texas has more extreme conditions for roofs which may explain the perception. Sustained winds of 70mph+ can and do happen on a yearly basis - also baseball sized hail and thunderstorms. It's pretty common to see a mild storm in the UK blow off some of the older roofs that probably should have been replaced a few decades earlier.

Yeah, the climate is an important factor here in Texas. We had a roofer out not too long ago and I asked him how long roofs typically last here, and he just sort of shrugged and said "they last until a storm damages them and then you get your insurance to replace it."

Sure, if your homeowner's insurance is paying to fix it and you never actually see the bill, it sounds like a more expensive roof still makes sense. But putting up the upfront expense of a tile roof when you know it's just going to break the next time there's a big storm is pretty unappetizing.

Asphalt shingles last 30+yr (depending on climate, use case and installation quality) before they run into issues.

25yr an unacceptably short lifetime for any professionally installed roof. That's like what you get when you install liquidated shingles that were sitting outside on a pallet for 15yr on a garden shed that has small tree bits falling on it and moss growing on it.

25 years didn't look right to me so I did some googling.

Apparently in US people tend to use asphalt shingles which indeed last 20-25 years[0]

[0] https://en.wikipedia.org/wiki/Asphalt_shingle

We know life time of solar panels, much less than infinity. And next we should ask why don't they sell same roofing material without extra complication solar panels if it really last for whole lifetime of building. Shouldn't that alone be massive market? Or allow someone to licence it?

You can already by metal roofs that will last twice of a shingle roof. Most people don’t choose it because it’s more expensive.

Aren't solar cells expected to lose efficiency to the point where they should be replaced after 25 years?

They run out of warranty, and obviously they are obsolete by that point. They still work, so. Technically speaking.

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