Exploring Slate Roofing - PODCAST TRANSCRIPT

Editor's note: The following is the transcript of a live interview with John Chan of The Durable Slate Company. You can read the interview below or listen to the podcast!

Megan Ellsworth: Welcome to the AskARoofer podcast, where all your roofing questions find their answers. Your hosts, Megan Ellsworth and Lauren White, peel back the layers of the roofing world to reveal the knowledge, tips and FAQs you've been curious about. From shingles to skylights, metal to asphalt, we are here to demystify the system above your head. So, get ready to ask, learn and explore the fascinating world of roofing one question at a time on the AskARoofer podcast. Hello, everyone. My name's Megan Ellsworth.

Lauren White: And I'm Lauren White.

Megan Ellsworth: And this is the AskARoofer.

John Chan: And I'm John Chan.

Lauren White: Yeah.

Megan Ellsworth: And we have John Chan here. This is the AskARoofer podcast. Welcome, welcome. John, let's dive right in and have you introduce yourself.

John Chan: Okay, great. So my name's John Chan. I'm one of the principals of the Durable Slate Company. We're a historic roofing company that works all over the country and actually even abroad. So, we work on slate, clay tile and copper roofing.

Megan Ellsworth: Wow, I didn't know y'all were international. That's so cool.

John Chan: Yeah, we've done a few interesting projects outside the country.

Megan Ellsworth: Super cool.

Lauren White: Very cool. What's been your favorite?

John Chan: Outside the country?

Lauren White: Yeah.

John Chan: Gosh, it's hard to say. Well, Trinidad was really cool because it was the Red House, which is their house of Parliament, and it got destroyed in a coup attempt back in the 90s and they had all kinds of issues with it. So, we were brought in 2016 first as a consultant and then we went there and trained up their guys and did all the most complicated parts of the roof so that they could keep it on a low budget and have guys in the future that they can actually use for historic roofing. But they didn't demand that these guys be experts right away. So it was pretty cool.

Megan Ellsworth: Wow-

Lauren White: That's awesome.

John Chan: Yeah.

Lauren White: Yeah.

Megan Ellsworth: Whoa. So how would you say slate roofing performs in various weather conditions such as heavy rain, snow, heat, what's its performance like?

John Chan: Well, the performance of slate, actually, all those historic roofing products are fabulous. If you go to any of the old European countries, go to London or Edinburgh or different cities in Germany, you'll see slate roofs that are literally hundreds of years old. So they work fabulously. The only problem with slate is that if they're not installed correctly, what happens is in wind storms and hail storms, you get major problems because the slate isn't installed correctly. So then you've got issues.

Megan Ellsworth: Yeah. Just out of curiosity, are those issues just like slate breaking and falling off or am I incorrect?

John Chan: Right. So just to give you an example, we took a tour of one of the Welsh quarries, Penrhyn Quarry and St. Asaph was finished in 1495. They didn't re-roof until 1968. It's documented that this roof was over 470 years old.

Lauren White: Oh my God.

John Chan: Right, exactly. So slate has to be hung on the nails. And what I mean by that is that the slate is punched or drilled in such a fashion that if you nail the slate in and it hangs on the roof, it can withstand a lot of wind, a lot of hail and everything else. But if it's over-nailed, you tend to put stress on the slate and put hairline cracks in it. So what happens is, a windstorm or a hailstorm comes and you've got a ton of broken slate.

Another thing that can be done is a slate's under-nail. So instead of nailing the slate flush and hanging on the nails, it's a little bit loose, so that nail protrudes a little bit, it's a little bit proud. So the slate on top sits on the nail and doesn't sit flush. So when somebody steps on it or you get wind or hail or something else, it vibrates and the slates crack and break.

Here's an interesting story. We did a new slate roof in Coral Gables, and it wasn't but maybe a month later, they had a Cat 4 hurricane direct hit and the GC called and I saw the call. I was just like, oh my gosh. I'm like, did anything happen? So I answered the phone and he said, "Hey," he goes, "just to let you know your new slate roof, not one slate missing with Cat 4 direct hit." And he said, "All around, the slate and tile roofs, they're all over the ground."

And so that kind of goes to show you a slate roof that's installed correctly, lasts. Like I said, it could be for hundreds of years. You go in Edinburgh, like I said, a lot of those roofs, they're well over 100 years old, a couple 200 years old. I visit the Delabole Quarry down in Cornwall, and he was telling me that their slates last between about 240 and 275 years. And I said, "That's pretty exact." He goes, "Well, yeah, because we know a lot of these buildings are hundreds of years old. So at that point, we know how old these buildings are.

He said, "This building right here is 250 years old." And he said, "The slate's still holding up," but he said, "We'll probably have to reroof in about 20 years." So that's the funny thing about natural slate and good slate products. Now there's different grades of slate, obviously. If you have low-grade slate from India or China or South Africa, some of those Brazilian slates, they're not so great. They're not going to last that long. Even your old Pennsylvania Black slates don't last that long, but really good top-notch slate like Buckingham, your slate from Vermont, your Del Castillo from Spain, your Welsh slate, like I said, Delabole out of Cornwall, those slates will last 150 years, 200 years, 250 years, sometimes more.

Megan Ellsworth: Wow.

Lauren White: Wow. That's amazing.

John Chan: Yeah.

Lauren White: So, kind of going off of that, considering how long slate can last, can you touch on the sustainability aspect and even the energy efficiency of a slate roof and compared to other materials out there?

John Chan: Sure. A slate roof, if you think about what slate is, it's a very dense rock. So, it started off as a sedimentary rock along the riverbanks, and then it got basically turned up on end and pushed down into the earth and you got a lot of heat and a lot of pressure and all of that heat and pressure made that slate super hard.

So what happens is cold air or hot air, tends to stay on that side of the slate, so it's got this natural ability to keep the weather where it's supposed to be. The other nice thing about slate is that when you lay it, it doesn't seal itself like shingles do, like rubber does. So it's got a natural ventilation and it can breathe. Now, I've got to make a little cautionary statement about that because there's a lot of installers that will install ice and water shield on the whole roof prior to installing a slate roof.

I'm not a big fan of that. The reason is, is that you've now cut off any ability for that air to move. And I've seen it time and time again, both in New Orleans, actually all over Louisiana and Florida where they've ice and water shielded a whole roof before putting on the slater tile and then you've got condensation issues. They've finished their attics, they crank the AC because it's 95 degrees out with a hundred degrees or a hundred percent humidity and they've cranked the AC down to 67 degrees and all of a sudden they've got leaks.

And I remember looking at this roof in New Orleans and she was telling me about her leak, and I said, "That's not a leak, that's condensation." And she said, "Why do you say that?" I said, "Well, it hasn't rained in about three weeks, yet your leak is active, it's wet right now, it's dripping." And I said, look at your thermostat. I said, "You've got a set of 67 degrees." And I said, "Just on the other side of this, you've got 95 degrees and probably close to 100% humidity." And she was like, "Wow." She's like, "Well, how do I fix that?" I said, "Unfortunately," I said, "whoever put this on, put ice and water shield on the whole roof." And I said, "You're going to have to come up with a clever way to vent the roof."

And how this comes about is this, the installation of these historic materials takes a lot of knowledge, training and time. And a lot of times you'll get roofers that aren't trained in it, and they just slam the roofs down as fast as they can. So the slates, they're over-nailed, they're under-nailed, the copper can't move, so it cracks. Copper expands and contracts a lot in the heat and cold, so when it cracks, you've got leaks.

So what they do is, they ice and water shield the whole roof, and that's actually your roof covering. And so it keeps the water out, but those kind of roofs don't last a long time. When they're slammed down like that and they're under-nailed, over-nailed, the copper can't move, you've got basically leaks all over it, but the ice and water shield is holding it out. That's what I was saying, the slate and tile roofs here in the US don't really compare to the slate and tile roofs in Europe on the most part because there's not the training program, so to speak here in the US that you have in Germany and France and the UK and there's this whole idea about speed and how cheap something can be done. And I think it's much better to do it right than slam a roof down. And that's kind of what happens here in the U.S.

Megan Ellsworth: Yeah, yeah, that's so true. Sometimes I wish we were a little more European, but you didn't hear that from me. So going into that with the amount of training it takes to put on these amazing roofs, are there any grants or incentives available when a homeowner is choosing slate roofing due to its sustainability and durability?

John Chan: Yeah. So it really varies from one state to another and what's available. We've done a lot of jobs where they receive grant money. Certain historic foundations, the government, it really depends on what your building is, when it was built, what kind of significance it has. But yeah, we've done a lot of work on buildings that have received all kinds of brands, and that's real helpful because slate, tile, copper roofs, they're very expensive materials. They're extremely long-lasting, and if you think about it, they're actually the cheapest roof by time, but the upfront cost takes a bit.

So I would suggest that anybody that has one that needs replacement, go and find out what kind of grants, what kind of things are available to help. But oftentimes these roofs are repairable because if you think back to a lot of these very old-time roofs, they were installed by people who came over here from Germany or France or UK or wherever, and many of them were installed correctly so they're very repairable.

And that's why I was saying, the St. Asaph Cathedral in Wales 470 years, but it had a lot of repairs over that time. When a windstorm came and knocked the slate or two off, it was repaired and repaired correctly. When the flashings wore off, probably lead because they like to use lead over there in the UK, when the lead flashings wore out, they tore out the slate around it, replaced the lead flashings and put the slate back in.

So that's usually a lot less expensive than going with a new roof. You can repair a lot these roofs. We've repaired roofs that are pre-revolutionary and they're still holding up.

Megan Ellsworth: Wow.

John Chan: Oh, yeah. In the DC area, we've done it in Charleston, we've done it in New Orleans. Homes are very, very old that we've restored and they're fabulous. But that's why I was saying, it has to be installed correctly. Or what happens is you have so many cracked and broken slates in trying to do a repair that it becomes unfeasible. And that's what happens when a lot of these companies come out after a hail storm and they try and total out a whole slate roof. And so many times it's repairable, but in their eyes, it's not repairable because they're not comfortable with doing the repairs on it and knowing that it'll work out in the long run because they're used to slates being over-nailed, under-nailed and flashing is being done incorrectly and all kinds of problems.

But like I said, gosh, any old city, and it's not just slate if you go to Venice or Madrid or these places that have tile roofs, there's a sea of tile roofs, meaning that 95% of the roofs are tile, and most of them are 100, 200, 300, 400 years old. They withstood all the hail storms, all the wind storms just by repairs. They don't always need to be torn off.

Megan Ellsworth: Yeah, yeah. I think that's cool and something we should get back to, more repair, less for replace.

John Chan: Yeah.

Lauren White: Definitely. So for a building to support a slate roof, are there any specific structural requirements that the building needs to have in order to support the weight of that material?

John Chan: Absolutely. So slate is a very heavy material. Standard slates quarter to three-eighths inch slate is generally about 850 pounds per square. That's a 10 x 10 area or 100 square feet. And then if you get say a denser stone like a Del Castillo or Buckingham, something like that, that goes up to about 950 or 1000 per square. And then also if you go with fixed slates, we put on a roof in Missouri a couple years ago, it required 12 semi-tractor trailer loads of slate because the slate was a half to three-quarter inch thick and it was also a very large roof. But if you think about the weight of that, that's going to be somewhere around, gosh, 2,500 or even 3000 pounds a square. So it's really got to be built to withstand not just the slate, but also if you're in a cold weather climate, all the snow that's going to build-up on that roof. So in building a new house for a slate roof, you've got to take all that into consideration.

Megan Ellsworth: Yeah, absolutely. That really slides beautifully into the next question, which is, compared to other roofing materials, I mean just the wait alone, slate differs, but you've touched on it here and there, but how does the installation process differ for slate from these other materials like asphalt, metal, what have you?

John Chan: Well, so asphalt, you just basically run some lines and you have an air gun and you just shoot them down as fast as you can. Metal, it kind of depends on what kind of metal roof you're talking about, but a lot of what gets put on in the U.S. here, you basically need a screw gun. It's either exposed nails or you've got the cleats where you just screw one in one right after another and just snap them on. And it is very fast. It's more of a production cycle than it is a long-lasting kind of a thing.

Whereas with slate, it takes a little bit to install it correctly. You've got to nail it just perfect. You don't have a lot of tolerance. Like I said, you over-nail it just a little bit and you've got hairline cracks. You under-nail it and the slate above it rocks on it. And so every single windstorm, every single hail storm, you get broken slates.

I remember inspecting a roof in Amarillo and it was less than a year old, and this is a big roof now, but it had over 300 missing slates. And the general contractor was trying to tell me that, "Well, that's pretty standard because by my calculator," he's like, "it's only 3% of the roof and it's not that big of a deal because I was told that a slate roof sheds like 5 to 10% a year." I said, "So it's natural for 300 slates to fall out?" I'm like, "That's insane." I'm like, "Think about this." I said, "You've got these big sharp pieces of slate that are flying off your roof every year. They could hit your car, they could hit your kids." He goes, "Well, how many should fall out?" I said, "Zero."

I said, "Yeah, I mean you might have one or two or something." As an installer, you tap it and you can usually hear that ring or that thud and know if it's cracked or not. But there's forklifts driving around, whatever, maybe you miss one or two and one or two gets installed and after a year, a couple fallout. That could happen. But to have that many fall out after a year is crazy. And for people to say that that's normal, that's normal if you're a gorilla if you're a shingle roofer and you're just slamming those down as fast as possible. But in general, yeah, you should have zero or less than 5, put it that way. You shouldn't have too many.

Lauren White: Yeah.

John Chan: So that's the thing. But the tolerance for the install isn't very high. And then there's also the issue of slate generally goes with copper here in the U.S, and copper has to be installed in exact way because when it gets hot or when it gets cold, it expands and it contracts and it does all kinds of different things. And if you don't install it correctly, you've got problems.

It's not the copper itself that's that expensive, it's the labor to install it correctly. And what I see here in the U.S, so often is caulk joints or solder joints where the person really doesn't know how to do that. And what I mean by that is that the solder joint is cold, meaning that the iron wasn't hot enough to draw all the solder back and give it a good joint or it wasn't cleaned well or it was in such a way that the copper will bind and tear.

So when the copper gets hot and cold, like I said, it expands and contracts. So let's say you've got a built-in gutter or a chimney or something where you've soldered the whole thing together, now it can't move. It can't move, but every time it gets hot, it moves, but it's got nowhere to go. So what happens is, the solder joints break or the copper itself will tear. I have actually seen where the copper itself tears because it was soldered so well, it's actually stronger than the copper.

But the force of the movement is much more than the strength of the copper. So the copper will actually tear. And sometimes it's a design issue where you have to get very creative with how you install it, but oftentimes it's just a lack of understanding. Over in Europe, most of the people there solder very little. They fold everything. They use pinched seams. And you can do that. you don't have to solder.

We do a little bit of both, we solder and we pinch the seams depending on the application. But there are certain times where you actually have to pinch the seams because soldering won't work. And I'll give you an example of that. There's a job we did in Washington D.C. It was the Norwegian Embassy, and they wanted pre-patina copper. Yeah, the whole thing of that is that the Statue of Liberty, all that copper actually came from Norway. Went from Norway, went to France. France made it, gave it to the U.S. and the Norwegian Embassy said, Hey, we want a green copper roof even though it's brand new.

And when I saw the specs for it, I was saying, "Well, you've got a lot of issues here." I said, "You've got a 20-ounce double locked standing seam roof that's curved, and then it goes up a wall, and then at the bottom, it's got a built-in gutter." I'm like, "Your specs show all these joints to be soldered." I'm like, "So you've got several issues with it." I said, "Number one is, it's pre-patinated so you're going to have to wire wheel all of that patina off, acid etch it to get it available for solder. Then you have to solder it and you have to be able to solder it so it doesn't run down your pre-patinated face. And then you're going to have to try and pre-patina all around your solder, plus your solder won't get that patina, so it's going to look God awful." I was like, "That's the first thing."

I said, "The second thing is, you've got this really long run and you're going to have this super long solder joint on there." I said, "What do you think's going to happen when it gets hot and cold? It's going to tear." I said, "It's an impossibility what you've got specified." And so basically what we decided to do was we made pinch seams. So we folded all of the copper so that it was all locked together, but it moved and nothing was soldered so that it could move and we didn't have to wire wheel anything. And then at the top where we rolled it out, we made, it's called bread pans.

So we took the standing seam panels and we folded it back around itself and it made a little cup to grab the backside standing seam roof, and it basically allowed the front roof and the back roof to move independently of each other. And it's vital in that situation because the front of it has got all these trees on and the back's a courtyard. So, the sun, the way it hits it when it comes over the horizon, parts of it are going to get a lot of sun, parts of it are going to get no sun and it changes through the day.

So different parts of that roof are going to get super hot while other parts are very cool, and it's going to make that copper really contort and the solder joints just won't work in that instance. So there's situations like that where you actually have to use pinch seams or it just won't work. And then there's certain times where you have to use a combination. We did a project also in Washington D.C. in Georgetown. Actually, the rumor is that's actually where L'Enfant and Washington drew up the plans on how to design the city.

Megan Ellsworth: Oh, whoa.

John Chan: Yeah, so it's a very old building and it's a restaurant now. And so before having a big copper roof that was low-pitched, there weren't any problems. But now because it's a restaurant, it's got all these vents, it's got these big HVAC units and it's got all these fixed points, and so all those fixed points can't move. So we had to basically make soldered seams around those fixed points. And then we used standing seam panels with pinch seams to allow everything to float. And then in the big pan, because it was almost made less than one-twelve pitch, it was pretty flat, we soldered that, but we locked it onto the standing seam, so everything floats and moves.

And you look at a project like that and it's like, I understand why they keep having to reroof it again and again and again and again because they're thinking, well, we're going to put a copper roof on there, should last a hundred years, but it only lasts five because all the solder joints keep breaking. And they go up there and then they caulk it and they put tar on it and every time it gets hot and cold, that tar and caulk cracks because it moves again.

And so they have to reseal it and they're scratching their heads like what's going on? Well, there is an instance where you need to solder everything where you're going to have the ice and snow build-up, and then you're going to need to lock everything to it so that it can move without binding and tearing. So I hope that answers the question. Maybe I went a little too far.

Megan Ellsworth: No, you went in depth.

Lauren White: Yeah, no, that was great. And I know we've touched on this a little bit already, but can you tell us a little bit more about the different types or grades of slate and maybe how a homeowner should choose? How do they choose the best option for their home and where they live?

John Chan: Sure, absolutely. There's different gradation systems depending on the country. Here in the U.S., we have S-1, S-2 and S-3. S-1 is the highest grade, meaning that it's going to last over 75 years. S-2 is a gradation that says it's going to start to deteriorate between 40 and 75 years. And S-3 means it won't last 40 years. So obviously you don't want anything that's an S-3 grade slate.

S-2 slates, they have been somewhat common in the old days. All of your Pennsylvania Blacks were or I shouldn't say all of them, but the most predominant Pennsylvania Bed Blacks were an S-2 slate, and you would generally start to see it flake up around 40 to 50 years. But the interesting thing with that is that Pennsylvania slate, if you repair it and maintain it well, a lot of those will last a hundred years, sometimes a little more, sometimes a little less unfortunately. But around that mark.

S-1 slates, it just means that it's over 75 years. So sometimes you'll have slates that are okay that are S-1, but you'll have very good slates are S-1. So here in the U.S., most of our slate today comes from the Vermont, New York area, Vermont Greens, Vermont Blacks, Reds, etc. And most of those slates will last over 150 years if they're maintained properly. And that's the thing, they've got to be installed properly and maintained properly.

Megan Ellsworth: Yeah.

John Chan: Then you'll have, like I said, your Buckingham or your Grayson slate that's quarried in Virginia that we don't actually know how long it'll last. The oldest Buckingham's still ring truly like a brand new slate. Originally way back in its old ownership, Buckingham had a guarantee that said it'll last for as long as the building stands. And I truly believe that. I truly believe that Buckingham would last hundreds and hundreds of years. I think that it's got the hardness of a Welsh slate or something like that. So you've got your S-1's, S-2's, S-3's.

But the main thing here that you've got to be careful of is your low-grade imports. Most of your slates that you get from Asia, Africa and Brazil aren't the greatest quality of slate for one reason or other. It's not that all the slates are bad, but a lot of what you'll get from those countries here in the U.S. is not very good. Spain, which is the largest producer of slate, is kind of like a mix. There are some really, really great slate from Spain and there are some slates that are good, and then there's some slates that aren't so good. And you really have to understand your Spanish slate and know who you're buying it from to purchase and use Spanish Slate.

You've got like CUPA for instance, they're your largest producer of slate. But when somebody says CUPA, they don't understand that CUPA's got like 28 different pits. It's like, which one are you talking about? Is it CUPA 14, CUPA 7? I mean, which one are you talking about? And that gives you an idea of your lifespan. Is it CUPA 14? That's a pretty good slate. Over there, you've got Del Carmen's. Del Carmen's are a great slate. If you go over to that part of Spain, you'll see Del Carmen's slates are 200 years old, so you've got some really good slate there.

A lot of your other European slates, they don't get imported here. Just due to that, they don't produce that much of it, so they use it locally. Like I said, like Delabole, for instance. Pretty much all of Delabole is only used in the UK. Yeah, it's a great slate, it will last 250 to 275 years, but you can't really buy it and ship it to the U.S. It was funny because I was talking to Morgan, the owner, I said, "So let's say I had somebody that just absolutely wanted Delabole. What would it cost?" He's like, "It's going to cost you right around $3,000 a square, and then we're going to have to package it and ship it to the port and then ship it to the U.S." He goes, "I'm going to guess it's going to be about 4,000 or $5,000 a square by the time it gets to you."

So it becomes impossible to use. Even Walsh slate if you look at Penrhyns slate, it's a fabulous slate, but it's pretty expensive. To get it over here and use it, you're well over a thousand dollars a square. It's approaching the price of Vermont Reds, which is always thought of as the most expensive slate.

So there's a lot of different slates from all over the world. The main thing is, you would have to select somebody that you trust if it's an importer to import that slate. And you also have to trust your installer. I've seen where switcheroo's have been done and the installer thought he was installing a certain product and he wasn't. And ideally, your installer knows what he's installing.

Oh, I forgot about another really good slate. It's from Canada. It's called North Country Black. We just used it in Texas in Austin at the Capital Business Center, and it's a fabulous slate.

Megan Ellsworth: Oh, cool.

John Chan: Yeah. So it's a S-1 slate, lasts well over a hundred years. So there's a lot of good slate, but you've got to pick the right slate for your house. And the biggest thing is the installer. Are they going to install it without over-nailing and under-nailing? Are they going to install it with the correct flashings? Are they going to install the flashings so that they move? And that's really what's key. So the longevity, yeah, you've got these S-1, S-2, S-3s, but in the real world, it doesn't mean a lot, unfortunately.

Megan Ellsworth: Right. Well, you're just sliding into all the rest of our questions so well. You're guiding the conversation. So you touched on maintenance and how important it is to not eventually needing to replace your slate roof. So what are those maintenance tips and tricks that homeowners should be aware of for their slate roofs?

John Chan: Yeah, they should basically get it inspected every year or two years, three years. And if there's any broken or missing slates... same on clay tile roof, make sure that they get replaced. Check the underlayment, any flashings. A lot of these old roofs, they were installed with something called Terne metal. What Terne metal is, it's carbon steel that was coated with a tin and lead coating. This was made by Follensby all the way up until, gosh, I want to say the early to mid-90s. And then with the EPA cracking down, they came out with something called Terne 2. And Terne 2 was that same carbon steel, but it had a tin-zinc coating to get away from the lead, and they had a lot of product failures.

So Follensby actually went out of business and Terne isn't made here in the U.S. anymore. But back in the day, we loved Terne, especially the Doublex Terne. The Doublex Terne was 26 gauge turn, and we used it all the time. But the thing with Terne is that it's got to be maintained. It's got to be painted. It has to be taken care of in a very certain way. And what I mean by that is that when you get condensation on the backside of Terne, it rusts from the underside out.

So that was another thing where when people put ice and water shield underneath, Terne flashings or Terne box gutters or something like that, the Terne metal roof would just rust out in sometimes a year or two where it should last 80 to 100 years if maintained correctly. But yeah, what you've got to do with those old Terne roofs and flashings and everything is, you've got to find any rust there is and use a rust neutralizer or a rust converter to stop the rust, and then you've got to paint it with a really good paint.

Unfortunately, they got rid of all the really, really heavy-duty paints that we used to use like 20 years ago. But if you keep them painted and stopping the rust, that goes a long ways. Keeping your gutters clean, making sure that the birds aren't building nests where they shouldn't or raccoons and squirrels aren't chewing up your lead pipe flashings or tearing up your chimney covers or anything like that. So maintenance-wise, it's good just to have it inspected and make sure all those little things are taken care of because they can lead to a lot of damage if they go and just keep on going.

Megan Ellsworth: Yeah, I bet.

Lauren White: Yeah, no kidding. And so in addition, you mentioned that hiring the right installer is really key for preserving this investment, your slate roof. So how can property owners ensure that they're hiring a qualified professional to install this material on their roof?

John Chan: Well, any really good installer is going to follow the National Slate Association Standards and Installation Guide, and your real slaters will actually be probably members of the Slate Roofing Contractors Association as a slate contractor. They have different categories of membership. You can be, I think a consultant, various different things and you can be a contractor, but to actually do a lot of slate, you would then be a slate contractor, a slate roofing contractor.

So there's a category called contractor, and there's a category called slate roofing contractor. So there's a little bit of it. And then also you want a company that's very, very well-versed in that type of roofing or that type of slate. So have they worked on that type of slate a lot? I remember somebody asked me once, they're like, "well, where did you get all this from? I've probably been on a thousand roofs and I've never heard of that." He was like, "How many roofs have you been on?"

And this is many years ago. I said, "I don't know, probably 10,000." And he looked at me in total disbelief, he said, "10,000." I said, "Oh yeah." I'm, "A durable estimator goes out and looks at 6 to 8 roofs a day." And I said, "So in a week, you're looking at 30 or 40 roofs. In a year, you're looking at 1500 to 2000 roofs." I said, "You know, in five, six years, if you're an estimator, you've been on 10,000 roofs." And I said, "That's pretty standard." And he was just like, "Wow." And I said, "A lot of the difference is that we work all over the country so we've seen ice dams where"...

I remember I saw this roof in Massachusetts, and if I hadn't seen the actual picture with the guy that actually took the picture, it looked like it was Photoshopped because there was over 10 feet of snow sitting on top of this roof. And you would think, how's that stay on there? You would think it would fall off. But you have extreme conditions like that. And then say down in South Florida, you've got hurricane-force winds. And depending on where you're at, you've got all kinds of different environmental aspects. Down in New Orleans, you've got flying termites if you've got uncovered wood, if you don't use drip edge, well, the termites are going to swarm and they're just going to eat your wood right out from underneath your slate and your slate will just fall off the roof.

Megan Ellsworth: Oh my God.

John Chan: Yeah.

Megan Ellsworth: That's horrifying.

John Chan: Yeah. We're getting ready to do this roof in Beverly Hills, they've got earthquakes. And if you don't make sure that... this is a clay tile roof, if you don't make sure that your clay tile and your copper can handle a little jiggle, well, it's all going to break. So you've got to be able to understand what's happening in that location. What are the extremes? Are you going to get 150-mile-an-hour winds? There are certain roofs in Florida where we used foam installation because you're going to have 150-mile-an-hour winds. So there's certain things that you want to do depending on what you're running into. And each location you just have to make sure that you follow along with what's the most extreme thing that's going to happen here.

Megan Ellsworth: Yeah. Kind of going off of that too, in the insurance world, extreme weather makes me think of insurance, how does slate roofing impact a building's insurance premium? And maybe its resale value, too?

John Chan: Well, as far as insurance premiums, there's such a wide range in that, depending on location and company. So there's, gosh, there's everything in the middle. But as far as resale value, it's huge because people want that old historic look and they fall in love with that history of it. So when you tear off a slate roof and put shingles on or put a standing seam metal that isn't historic, it throws everything off and that resale value, it's going to go down the tubes.

It kind of depends on what it looks like and how it's taken. But a lot of these, especially these synthetic roofs... Here's a funny story. A few years ago in our home office, literally like a mile from our shop, there was a hailstorm and there was these two old Victorians, and one of them, we tore the roof off. They were both Pennsylvania Black slates. One of them, we tore the slate roof off, installed a new North Country Black. All copper flashings, looked beautiful. And across the street, they put a synthetic on. It was a synthetic roof that was Black. They used copper flashings.

And one of our guys said, "Oh my gosh, this is crazy. They look identical because the North Country Black lays so flat, it looks like a synthetic." And he's just like, "Wow." And I was like, "Really?" And this is the funny thing. So a year later, our roof looks the same. That roof is all curled up. It's discolored and it looks like hell. And so that's the funny thing, it's like you get that contrast of longevity. Slate's a time-tested material. It's been around for centuries.

The quarry that we went to visit in Wales, they were quarrying all the way back in the 1400s. So these old slate roofs, these old tile roofs, they're time-tested. They've been around for centuries. Many of them have lasted for centuries. But here in the U.S., things are a little different where a lot of people are more of like a throwaway society. They want everything fast and cheap. And so you get these synthetics that look like slate, at least in the beginning, but they're just terrible roofs. None of them last very long.

And then also the whole install, instead of installing it correctly, making sure that all the slates are nailed correctly so that they last, a lot of these roofs, they're just slammed on. And that's why some of them have such difficulties in storms. That's why you have so much breakage sometimes in hail storms or wind storms, these newer roofs because they're not installed correctly. They're over-nailed, they're under-nailed so they have no give. So, you've got wind, you've got hail and all of a sudden you've got 300 slates missing. And instead of putting it on right and lasting a hundred, 200, 300 years, you've got these issues. So that's what you've got there.

Lauren White: Amazing. Is there anything else you think property owners should know about slate roofing?

John Chan: Well, it's a beautiful roof, and you just want to make sure that you select the right look for your home; the right color, the right texture, the right consistency. You want to make sure that you choose the right flashing, the right gauge of flashing and most importantly, your installer. Your installer is the most important part of that.

Lauren White: Huge.

John Chan: And it's kind of strange, but price isn't really where you want to go with that. You want to go with a time-tested installer that's installed quality roofs time and time and time again, and the nailing and the flashings are vital to a perfect slate roof.

Megan Ellsworth: That is such great advice and so true. I think you've given the home and building owners that listen to this podcast, some really great tips for picking out their next roof. I hope they all go with slate. I mean, like you said, it is truly time-tested without a doubt. And I think that's so cool. And I'm with you on the sentiment of being a culture of repair rather than replace.

John Chan: Yes.

Megan Ellsworth: So, thank you so much, John. Your wisdom has infected us today.

John Chan: Well, thanks for having me. It's been great.

Lauren White: Thank you so much.

Megan Ellsworth: Awesome. Yes, thank you. And to everyone out there listening, you can learn more about the Durable Slate Company on their directory on rooferscoffeeshop.com and askaroofer.com. You can also follow them on Instagram and Facebook and all of the places. Make sure you stay up to date with all of the AskARoofer podcasts. So click the little bell button and get notifications every time we post a new episode. Lauren, this has been a great episode.

Lauren White: I know, I learned so much about Slate that I had no idea about.

Megan Ellsworth: Yay.

Lauren White: Thank you, John.

Megan Ellsworth: I know. Same.

John Chan: You're welcome.

Megan Ellsworth: Thank you all so much, and we'll be seeing you next time on the AskARoofer podcast. Great job, John.

Lauren White: Yay. That was awesome.

Megan Ellsworth: See how passionate he is about it.

Lauren White: He truly loves what he's doing. All the projects that they've worked on in D.C. and in the U.S. and even abroad, some of those amazing stories that he had about slate roofs that are lasting hundreds and hundreds of years is truly amazing.

Megan Ellsworth: Yeah. And how they can be accurate with how long they'll last because they're like, oh yeah, Joe Schmo's house down the road was built in 1492 and it still has the same roof on. That's crazy.

Lauren White: I know. Yeah, really wild. And just hearing them talk about the different quarries and all the different grades and styles of slate roofing that are available to people is pretty... I mean, I thought it was interesting.

Megan Ellsworth: Yeah, I thought it was really interesting, too. It made me think, I think a few years ago, Tim and Heidi went to the Slate Association's Annual Meetings and got to see a slate quarry up in Vermont, and I remember them both just kind of-

Lauren White: That'd be so cool.

Megan Ellsworth: Yeah, being blown away by how cool it was, and getting to see the slate made right there or chipped and shaped right there in person was really cool.

Lauren White: Yeah, that's awesome.

Megan Ellsworth: Yeah, I think that we should definitely have an episode with him again on clay tile roofs.

Lauren White: And copper, because apparently slate and copper go hand in hand, which I didn't realize.

Megan Ellsworth: Yes, I didn't either. And that building he was talking about for the Norway Embassy that it was interesting it was funny that they wanted the copper patinated already so green rather than copper.

Lauren White: Right.

Megan Ellsworth: That's fun.

Lauren White: I know, I know. And just slate is such a sustainable material because it can last up to 200-plus years, which is pretty incredible. Especially because the trend now with home and building owners is we're all about sustainability, which is great. So slate's where it's at, too.

Megan Ellsworth: Yeah, slate really is where it's at, because also like we mentioned quite a few times in the podcast leaning into the repair versus replace mentality, and I think that's something our country kind of isn't all about and we could be more about. And not just our country, a lot of places in the world and just the world in general, we're kind of a what's next society, rather than I'll just keep what I have and make sure it's nice.

Lauren White: Definitely. Yeah. But yeah, lots of fun facts and interesting info, historical info about slate roofing and looking forward to having John on the podcast again.

Megan Ellsworth: Me, too. And hopefully one day I have a slate roof.

Lauren White: I know, definitely.

Megan Ellsworth: All right, well I'll see you on the next one, Lauren.

Lauren White: Yeah, I can't wait.

Megan Ellsworth: See you then. If your roof needs answers, subscribe now to the AskARoofer podcast. We've got your questions covered, one episode at a time. Go to askaroofer.com to submit your questions and learn more. Stay tuned and keep those questions coming.