#5 - Building Science Myths Debunked with Dr. Joe Lstiburek

Jess Kismet (00:00)
Hello and welcome to the Building Sciology Poddie where we talk about better buildings to live and breathe in. Today's episode is a special one. I'm absolutely thrilled to be joined by one of the giants of building science, Dr. Joe Lstiburek. If you're in the building science industry, this man needs no introduction. But if you have not heard of Joe, he is a principal at the Building Science Corporation and has often been referred to as the godfather of building science.

He has been at the forefront of energy efficient and durable construction for decades and is an international leading voice in creating healthier high performance buildings. He is buildingscience.com. This is going to be a good one and I'm so pleased to have him on the show. So welcome Dr. Lstiburek

Joseph (00:41)
Well, it's a pleasure and please, it's Joe. The doctor is only for attorneys and bartenders late at night. Okay.

Jess Kismet (00:50)
Thanks, Jo. Alright. So I have just completed your Building Science Fundamentals course. This was 4.30am starts for me here in Adelaide, which was very definitely worth doing. And I must say, I particularly enjoyed learning highly technical terminology such as insulate up the wing wang wazoo.

Joseph (01:12)
Those are metric terms, are they not? One wing and wang is two wazoo's? I thought.

Jess Kismet (01:15)
Yeah, yeah.

I think I'll be implementing that in my reports moving forward. All right, let's kick off. There is so much to cover and I'm gonna do my best to cover all the essentials. But first off, I'm gonna start with this question. What is the biggest building science myth you've had to bust in your career? What's the biggest misconception you've had to, that you hear over and over again?

Joseph (01:41)
Well, it's okay for buildings to get wet if they dry. Let me repeat this. It's okay for buildings to get wet if they dry. The problem is, is we've dramatically changed the fact that the buildings no longer dry. And so because they no longer dry, we have to keep them from getting wet. And people seem to think that, hey, look, insulation is good.

And more insulation is better. Well, you know, the second law of thermodynamics says you can't get your money for nothing and your chicks for free. Nothing is, you know, whatever. The insulation is added, reduces the energy flow and drying requires an exchange of energy. So the more we insulate, the lower the drying potential. And to stay in moisture balance, we have to reduce the wetting potential.

The problem is we're insulating and we're not reducing the wetting potential. so buildings are going to crap. And before, just for the record, I love efficiency and more insulation. I'm an engineer three times over and I'm born with a genetic defect. It's the efficiency gene. I can't help myself.

I want to be more and more and more energy efficient. Yay. Woohoo. But I'm an old engineer who's lived through the physics wars and found out that, look, you just can't change the energy flow without changing the boundary conditions. And that's been a myth and a fight that we're still having. We're in the middle of it.

in North America and we have, and I'm arguing with the cults. I'm arguing with the green cult, the carbon cult, the activist cult. So if you can't do math or physics, you basically yell and march on the streets and you ought to say that, well, that you're just, you just don't get it. And the answer is no.

I get it. I want all of these things to happen. But the physics need to be followed. And if you don't understand the physics, you can't implement policy. by the way, we haven't, it's not a happy state of affairs over here, okay? You know, we have floods, have earthquakes, we have fires.

California had a wonderful time not too long ago. And a lot of these things could be avoided with the correct energy efficiency, but a lot of these things can be made even worse with the wrong efficiency. And we're at this turning point and it would be nice to avoid problems. I've been in Australia

bunch of times and I love the place. You taught me to surf, okay, not very well. And I want to have you folks stay out of the dumb stuff that we did. I think you should do your own new dumb stuff and be innovatively dumb, but you shouldn't do stuff that we did incredibly badly that you can avoid.

Jess Kismet (05:32)
Those things are like, I know one of your biggest issues, was that just Canada? Don't want to get the too confused. I don't know, there was the, we talked a lot about the stucco or the render issues. We use render all the time in Australia. It's one of our most favouritest ways to finish a building and it's used as waterproofing. But you were saying in the course that render should be used as a sacrificial coat to absorb water out of the bricks and should just kind of fall off and be replaced every few years. That's not how we approach it here.

Is that a dumb thing that we're doing?

Joseph (06:04)
Okay, yep. All right. There are various kinds of renders and I have to learn to speak Australian, okay? So, all right.

Jess Kismet (06:15)
Yeah, it was really hard

work for me to like translate all the American.

Joseph (06:19)
All right, to

me, render is a thin, cementitious thing that you spread on the outside of something. And in the old days, we would, you know, we called it stucco or render and we'd put it on three or four layers of brick and we would call that a mass wall. And it worked really great. Now, you know, one to 2 % of the water that is on the face of the render

or the stucco passes through it. And if it goes into brick, nobody cared. Hey, wow, yeah, okay, I got a whole bunch of whatever. Well, if I have, you know, render on a thin layer of wood or another material that's moisture sensitive and it enters, it's gonna get wet. Now, back in the day, it was okay.

because those walls were made out of wood frames and studs with no insulation. So things got wet, they were able to dry because there was energy available. Well, now we fill them chock-a-block full. That's an imperial term, not a metric term. And guess what? The energy flow isn't there anymore. Yay! All the water still enters.

Jess Kismet (07:37)
Thank

Joseph (07:47)
Okay, now we got a problem and they rot. And so what we've learned in Canada first, and we then exported that really bad technology to the United States because they were taking our best hockey players, just letting you know. And we found out we had to provide drainage between the renderer and the water sensors materials. And the drainage

is usually, you know, a millimeter or two creating a gap. we used to, we get that with a bumpy building paper covered with another building paper. Then we have a metal lath and then we have the render. So we have the render, the wonderful render with a metal lath over two layers of building paper with a gap between them. So when the render leaks, we provide drainage.

and that water is drained to the outside. Well, we never had to do it. We never did that before. Well, you didn't have to because the wall was uninsulated and you had enormous energy to dry it. Wetting followed by drying. Well, so you're telling me that if I have an old building that's been around for 56 years and it's working just fine, that doesn't have drainage.

And I insulated because of a government program to save energy. want to save the planet. We are in the lower of the carbon, whatever. We want to save money to buy a player to play rugby against the New Zealanders, whatever the reason is. We're in trouble because that water stays in there and the building fails. So you're telling me you can't just go to an old building.

and fill it with insulation if it has water sensitive materials. That's right. But if it's an old building with two or three layers of brick and you insulate it on the inside, relax, take a volume. That's OK. The brick can stay wet or longer. Well, how do I make the and how do I provide energy efficiency and save the planet and whatever with the render?

over water sensitive materials. Well, you might have to put another render over the existing render with a space between the new render and the old render that's drained.

Jess Kismet (10:24)
I don't know how we do it in Australia.

Joseph (10:25)
Well, that's not what

the women, but that's not cheap. Well, you can't get your money for nothing in your chicks for free. And by the way, if you were really, really smart, you'd put a layer of insulation over the existing render, continuous external insulation, and then put a gap between the outside surface of the exterior insulation and the new render. Whoa, now you're kicking butt.

What you could do is you could put grooves on the outside layer of the surface of the render. It would be groovy. It's a 60s technology. And we could then have drainage in the grooves over the new render, over the continuous insulation over the existing render. And then you can fill the cavity with

Ground Up Newspapers.

Gloria Vanderbilt's blue jeans with borates, anything, and you're in good shape. But by gosh, if you just fill the cavity with insulation and you don't deal with the rainwater wetting, you're in big trouble.

guess worse.

Balls can also get wet from the inside. You know, let's get rid of the big holes and make it airtight. you know what an Australian human is? An evaporatively cooled, unvented combustion appliance. You're a power humidifier that vents into the damn space. So you generate an insane amount of moisture. And apparently some of you actually know how to cook, right? you have plants and stuff and so.

All of a sudden the interior moisture goes up because you've reduced the air change to save energy. Yay! Well, that moisture, if it now gets into the wall that you haven't addressed, my gosh, that would probably cause problems. But if you warmed up the wall by putting continuous insulation on the outside, yeah, you could tighten up on the inside and you could have

plants and evaporate stuff and listen to the nonsense from the Center for Disease Control in Atlanta saying that COVID risk is reduced with humidification. I'm not going to, I have enough trouble with them. So you can have a higher level of humidity and your wall isn't going to rot, you're going to be energy efficient. But wait a minute, I had to put stuff on the outside because I'm changing the inside.

Yeah, well, I don't want to do that. Then don't change the inside. Well, I want to put insulation in the wall while you have to change the outside. Well, I don't want to do that. put, okay. That's the message.

Jess Kismet (13:42)
Okay. So, I mean, our building code, we lag behind the rest of the world as it is as a country, as we've already sort of discussed a few times. And in South Australia, where I live, our building code has just been put on pause for another 10 years. So the code that we've got, I mean, maybe that's a good thing. Maybe if we're not insulating more and making buildings more airtight, that won't be as, you know, hot and humid inside, we won't have the same moisture problems.

But the star ratings have gone up. So we have a star, you have Energy Star, is that right? Yeah, we've got something similar. They're just called star ratings. So it's the same concept. Still trying to improve the energy efficiency of our buildings, taking away the condensation management clauses or sort of stopping them right at a point where they're just starting to be understood and implemented.

Joseph (14:16)
yeah. yeah.

KAH-HUH!

Jess Kismet (14:41)
So, I mean it.

I mean, we've got a housing crisis here too. Have you got a housing crisis in the US?

Joseph (14:49)
Do I have, I'm sorry, say again, do we have a?

Jess Kismet (14:51)
A housing crisis. Yeah.

Joseph (14:53)
Yeah, we do.

We have an illegal alien crisis. We have homeless people. We are running into affordability issues with housing stock and housing spaces. And so we got a population crisis, a homeless crisis. And I would like to

to keep the people and have them safe and sound and have them live inside, not on the streets, not like normal people to be able to afford houses that last a long time and don't make them sick. And we're okay.

Jess Kismet (15:37)
Mm.

Joseph (15:42)
My observation now that I'm an old crotchety guy is that things become intolerably bad and then we intervene. And they're becoming intolerably bad and we're intervening and we're beginning to intervene correctly. I grew up in Canada, I'm now in the United States, but one of my favorite quotes comes from Winston Churchill.

And he said, describing Americans, said, Americans can always be counted upon to do the right thing after all of the alternatives have been exhausted. Well, we've exhausted the dumb things in terms of our building enclosures and mechanical systems, and now we're beginning to do smart things. But we're doing the smart things because we did the dumb things. And there was a learning curve.

In the United States, we did something called the weatherization program, the low income weatherization program. would actually pay people to go and insulate low, you know, low income poor people's buildings, which was spectacular. But we've rotted, we rotted a lot of them and we made a bunch of people sick and we killed some of them because of carbon monoxide poisoning.

Well, now we're very sophisticated. You know, the programs know how to insulate them in a way that doesn't cause the buildings to rot and be moldy and to provide combustion safety and ventilation so that we don't have carbon monoxide poisoning. We don't make people sick. But it took 25 years and it would be nice for.

you folks not to have to spend the 25 years you should, you know, hey, this is easy. Boom, boom, boom. You'll have other problems because your materials and your trade bases is, is, is different and unique. mean, you, you, you, you, you play, you know, football with a round thing sometimes, and then you play football without pads. mean, I, I, you know, what is going on? Um, okay. That's a,

Jess Kismet (17:47)
you

Hmm.

You

Joseph (18:12)
bad

humor, but I'm saying that you're in a position to avoid the problems that we had in Canada and the United States. And it'd be sure nice to help you stay out of the dumb stuff that we did. you've got you've got some you've got unique practices and and some of the stuff I

I smile at and I'm like, wow, we could never do that over here on the other side of the Pacific. But man, would be a good idea. I mean, there's some wonderful stuff that you have. Your wood framing is different and you have more wood in it than you need. And you already know that. mean, your, what are you, your dwangs or whatever the heck they're called, dwangs.

Jess Kismet (19:07)
Noggins.

Joseph (19:09)
Whatever I mean, I like, you but

Jess Kismet (19:12)
I had to learn that one

as well. I think I was reading an American book during my studies or an American website and I was like, what is it? To us that just sounds like it's an insult.

Joseph (19:19)
But no, I...

But

it's, you have such a magnificent opportunity to do things incredibly well and stay out of trouble because you are.

Jess Kismet (19:37)
But.

Joseph (19:42)
20 years behind the rest of us who did really stupid things.

Jess Kismet (19:47)
So, mean,

I'm just trying to sort of boil this down into something really succinct. If we are insulating our buildings up the Wing Wang Wazoo and creating drying issues in our buildings because we're changing the energy exchange and the only way to improve that is to stop the water getting in from the outside.

Am I correct in saying that external cladding is not meant to be the rain, that's not the water protective barrier? I mean, in Australia, what we do is we have a timber frame clad, we stick a sometimes very poorly installed membrane on the outside of the frame, and then we stick some lightweight cladding to it, or we put some bricks up. That's basically our housing. brick, there's usually a vented cavity behind brick. So although it absorbs water, there's movement behind there that

dries out that brick. That's the idea anyway. And the lightweight cladding just usually...

Joseph (20:47)
But let me tell you, the brick space is filled with mortar droppings. Well, that doesn't work. have to see how do you handle the mortar droppings? Well, in new construction, it's pretty easy. In existing construction, you have to reduce the wetting of the brick and the water leakage of the brick. And sometimes that means, wait for it.

Jess Kismet (20:53)
Yeah, yeah, exactly.

Exactly.

Good question.

Joseph (21:17)
put a rendering over the brick.

Jess Kismet (21:20)
That's what we kind of tend to do.

Joseph (21:24)
Yeah, but I mean, you have all kinds of possibilities and good possibilities, not bad ones.

Believe it or not, let's say that you blow your cavity with, you've got wood cladding over, you know, thin membrane paper, whatever, and you fill it with insulation. Well, one of the ways to increase the drying is you put wedges in between the laps of the siding. And you're

Jess Kismet (22:03)
Yeah. Yeah.

Joseph (22:07)
You're kidding. So wedges help me. And I said, yeah, big time. Well, what if I don't do that? Well, your the paint will fall off and your signing will rot. Well, how do you know that? How do you know that? Well, because we did that. My, by the way, my first official peer reviewed paper that, you know,

Jess Kismet (22:19)
exciting for Australians is cladding.

Yeah.

Joseph (22:36)
I mean, I wrote a lot, the first one was actually peer-reviewed and published. you know, I got an award for it was called Insulation Induced Paint Insighting Failures. And I basically said, well, look, you insulate the cavity that's been uninsulated and the paint falls off and the cladding or the rendering rots. And, well,

Jess Kismet (22:49)
Yeah, right.

Joseph (23:06)
What do need to do? Well, you need to provide drainage and drying. Well, how do you do that? Well, put in some wedgies. So yeah, and they gave me a master's degree. mean, I'm a legend. I can't help.

Jess Kismet (23:15)
Yeah.

Woo woo!

Well, it sounds like, you know, where I work at Climashore, it's a company called Climashore, we advise people to use air gaps behind their siding or their cladding. And that's, it sounds like, you know, for the construction methodologies we have in Australia and the sort of cost, the cost controls and things that go around it, it sounds like

that's the best way that we can adapt our construction methodology. So that's, I think that that's reassuring, just allowing air and drainage behind that cladding.

Joseph (24:01)
Well, can I tell you something else you can do? You can provide flashing and drips that shed the water off the surface before it gets absorbed. And the flashing and the drips can be elegantly understated that you're not going to notice them. And so a lot of things can be done. Let's reduce the amount of water that's running on the surface.

Jess Kismet (24:05)
sure. Love it.

Joseph (24:31)
of your rendering and cladding by having drip edges. And the drip edges can be done in a way that people are not going to notice that they're there unless you're an insane professional. And so you reduce the amount of water that's running on your surfaces by kicking it away. That way, there's less water able to be absorbed into the assembly. And then you handle it.

Jess Kismet (24:36)
Mm.

Joseph (25:00)
water that's entered the assembly by providing drainage and ventilation behind the cladding in such a way that nobody knows that you've provided drainage and cladding. So you want to be...

Jess Kismet (25:10)
Yeah. Okay,

well, it's kind of reassuring. sounds like, you know, these systems work. We use them a fair bit in the space that I work in. it's, know, for what we're doing in Australia, it sounds like we're on the right track. So that's, I find that reassuring. We do have a lot of buildings in Australia though that don't have any drip edges. We have a lot of flat roofs and parapet walls. So, you know, it sounds like someone who works in this sort of...

moisture management, I guess you could say, space, that always, that concerns us. Do you have that in America? In new buildings? that because it's a very, it's an aesthetic that people want.

Joseph (25:46)
yeah, I win.

No, no, and so guess what? What, you know, you're with a flat roof and a parapet, the existing membrane can be, which is called the roof membrane, is an insanely good air and vapor barrier, right? So you can put an inch or two of rigid insulation on the top of it. And then you can put a filter fabric over the top of that.

Jess Kismet (26:09)
Mm.

top. Okay.

Joseph (26:20)
with some stones. And so, you know, what you do is you choose a material that has a little bit of drainage underneath it that doesn't, that can handle being wetted. It's in other words, it's easier to do a flat roof.

Jess Kismet (26:23)
Hmm.

Joseph (26:38)
It's true from underneath because you can do the flat roof on the top and you've got you've got this magnificent air barrier that you don't calling an air barrier. It's called your roof. Now, the biggest risk is the parapet and you have to deal with the issue of condensation and accumulation in the parapet. And there's we don't want to do that in North America because we screwed it up for so long.

Jess Kismet (26:39)
Mmm.

Joseph (27:07)
Another paper that I wrote that I got into a lot of trouble with, I then became, no one knows, called parapetitis. So I coined the disease of how roofs connect to walls at parapets and how you don't have to, it's not just dealing with rainwater, you have to deal with airflow and diffusion. And you have to connect the air control

and the thermal control of the flat part of the roof to the wall. And in concept, it's very, very simple, but in practicality, you end up having to be clever. And you folks are pretty damn freaking clever once you know what the rules of the game are. And you get some real opportunities. And we don't have a lot of flat roofs residential.

We have an insane amount of flat roofs commercially and in high rise apartments. And we've gotten good at them simply because we were very bad at them early. believe it or not, we learn more. Our roofing systems are more advanced than our wall systems because roofs see a greater stress than walls. So because roofs see a greater stress than walls,

Jess Kismet (28:20)
Mm.

Joseph (28:37)
they go to crap faster. And because they go to crap faster, you have to fix them sooner because they're the ones that go, know, where the building touches the sky is the greatest stress. And that's not as stressful as the sides. And I think I've said this in the past, the biggest stress is where the building touches the sky, followed by where the building touches the ground. And then you have to connect between the sky and the ground to stay out of trouble.

Jess Kismet (28:43)
Thank

Joseph (29:06)
And if you don't get the sky part right and you don't get the ground part right, you'll be wasting your time on the sides.

Jess Kismet (29:15)
Mm-hmm,

mm-hmm. I've got so many more things I wanna talk about. Okay, we've got the perfect wall. I feel like we have to touch on the perfect wall. But then I wanna talk about OSB and ply because that's a really big discussion point in Australia and which one's better. And bushfire resilience, like I've got so many things.

Joseph (29:38)
Well, let me answer that right.

Let me answer the plywood and OSB.

Jess Kismet (29:43)
Okay, please.

Joseph (29:48)
OSB is not in the same league as plywood. And plywood is not. OK, and by the way, and plywood is not in the same league as boards. All right. Wood boards. I I tell youngsters that we used to go to forests and cut trees down and cut them into boards and build boats.

Jess Kismet (29:53)
Okay, you heard it here folks.

boards.

Joseph (30:17)
and sail them around the world. Try doing that with a sheet of OSB. I call OSB the spam of wood. I call spam the OSB of luncheon meats. You take a tree and you grind it through and you smoosh it together with, you know, the secret herbs and spices and whatever. And I call it, I call it was wood. It was wood once, it ain't wood no more. Now,

Jess Kismet (30:22)
Ha ha.

Mm.

I've heard it

called old soggy board here in Australia.

Joseph (30:48)
Well,

I view engineered wood as an insult to wood and engineers. right. And so but look, we're not going to be building out of thousand year old trees. We're going to have to figure out how to deal with OSB and plywood. And the answer we have, we just have to keep them drier. We have to protect them from liquid water, more

than we have done traditionally. I never had to do that before. Well, you built out of real wood. It gets worse. OS plywood was replaced by the OSB. The OSB is being replaced by paper face gypsum sheathing, right?

Jess Kismet (31:25)
Mm-hmm. Mm-hmm.

Joseph (31:40)
ready for a really bad joke?

Jess Kismet (31:43)
always.

Joseph (31:44)
We're lining the buildings with paper on the outside and on the inside. We're building paper buildings. Even the dumbest of the three little pigs didn't build his house out of paper.

Jess Kismet (31:56)
You know, we're basically building our houses. We're living in Petri dishes. That's kind of how I look at modern housing. It's all porous materials that are at risk at any moment of getting wet and yucky.

Joseph (31:58)
That's good, that's good.

Open.

But you see, but

we can work with that. I don't have a problem building out of paper and moisture sensitive materials as long as I drain the water out of them quickly enough and I design things in such a way that they're able to dry quickly enough. So we don't have to use thousand year old trees and rocks and not have any insulation.

Jess Kismet (32:37)
Mm-hmm.

Joseph (32:39)
I want to have an enormous amount of insulation. I want more insulation than you're even thinking of putting in the damn buildings right now. And I don't want to cut down thousand-year-old trees. I want to recycle materials. I want to do all of this. But I have to understand the energy relationship with the durability of the material relationship. And that's the piece that's not coming through.

Jess Kismet (33:06)
So, all right, quickly question about bushfires. We touched on the California fires earlier in the conversation and in our course you mentioned that they were due to vented roofs. We have obviously a very high fire bushfire risk in parts of Australia and our sort mould issue started in the higher risk areas in the roofs because they were not being vented properly to stop embers getting in.

they were getting all wet.

Joseph (33:37)
No, no, no.

Let me stop you. The roofs burned because they were vented. Vented roofs are an insane fire problem. The way that you handle fire in roofs is you don't vent them. Well, we have to vent the roof. We have to vent the roof. No, you don't have to freaking vent the roof. People vent the roof because, I don't want it to rot.

Jess Kismet (33:58)
Yeah, well, yeah.

Joseph (34:07)
Okay, well we have all kinds of ways of removing moisture without having to have air do it for you. And so one of the easy ways, what's frustrating to me, and that's why I really like Australian wine, helps me get through the difficulties of frustration, is I've been warning people for almost 35 years.

that vented roofs are a problem with fire. And it's easy to build an unvented roof from scratch. But my God, what do we do with the existing building stock to reduce the risk? And the short answer is, that we close the lower vents so that they're not having air come in at all. And the upper vents, the holes that had air leaving,

You cover them with a fireproof, vapor-open material. What happens is that you're venting the roof by vapor diffusion. The water molecules leave because they go to a lower concentration. And this freaks people out that when you add moisture to air, you reduce its density so it floats, it's buoyant.

So the moisture laden air goes up even without having air circulation. It just floats up. It's called hygrig buoyancy. And those little bastard water molecules, those really evil things that hurt you, they pass through the vapor, open material. But I don't have an exchange of air. And because I don't have an exchange of air, I don't have the embers.

being drawn into the roof. And so, by the way, it's kind of funny, not funny, but a couple of the buildings that survived the California fires, I had some indirect involvement in them because they weren't vented roofs.

Jess Kismet (36:24)
Yeah.

Joseph (36:26)
Well, I can't retrofit them. Yeah, you can. I mean, I explain this to the people in California and in Florida. Just freaking close the lower vents and cover the upper vents with a vapor permeable air control layer and it's not going to rot and it won't burn. mean, come on, people, we can do this. I guess even better. Are you ready for this? Unvented roofs don't blow off in hurricanes.

So we reduce the risk for high wind events and we solve the problem with fires. I mean, I don't get it. Well, the roofing companies require venting to have the warranty. They don't understand how their products work. They think that moving air under the underside of the roof will reduce the temperature of the shingle. And the answer is it doesn't.

dominant heat transfer is radiation and if you want to handle that don't install a dark shingle, install a white shingle or a light shingle. Good luck with that. So the color is more important than venting. And guess what? know tile roofs and metal roofs last a lot longer than asphalt shingle roofs because tile and metal run in a colder temperature and you don't have to vent them.

Jess Kismet (37:53)
Mm.

Joseph (37:54)
So, you know, when you re-roof your roof, when you have to, when your shingles are done, you know, change the shingle to a white shingle, because white shingles last twice as long as dark shingles, because they're cooler. I know, I'm a legend, I can't help myself. Metal roofs are a lot cooler than asphalt shingle roofs. know, duh.

Jess Kismet (38:16)
We

have a massive love affair in Australia with Colorbond Have you heard of Colorbond It's basically metal roofs. But it's like the branding that we have here and they're, you know, highly durable roof sheets and everyone loves the really dark colours just because they look nice.

Joseph (38:34)
But you see,

a really dark metal roof isn't as bad as a really dark asphalt roof. And the short answer is, you know, so what? The metal isn't as temperature sensitive from a durability perspective as asphalt is. So, yeah, the color doesn't, it's gonna last longer than...

Jess Kismet (38:40)
Hmm.

Mm.

Joseph (39:00)
all of us combined, all right? But what you need to do is you need to provide some means of getting the moisture out without having to have air carry it. Because if you have air carrying it, that's a fire risk. they have two major problems and well, three, two major problems and another one that they're dealing with now. The first one was the vented roofs.

Jess Kismet (39:01)
Mm.

Yeah.

Joseph (39:29)
The second one is vented walls. You know, they're all into the rain screen and the air space between the cladding to provide drainage. Well, if you have a half an inch to an inch gap, that's a fire risk, but you don't need more than an eighth of an inch gap for drainage. So they don't understand that if you, by the way, you know, the Grenfell Towers in England, the 80 people that died, they died because they had a two inch space between the cladding system and the wall.

Jess Kismet (39:59)
Yeah.

Joseph (39:59)
It was like,

it was insane. If it's less than a half an inch, which is what, you know, 12 millimeter, you guys are metric. I don't know what any. Yeah. So the boundary layer friction of the two surfaces starved the fire. So believe it or not, if you have a very narrow space, you don't have to fire stop it because the air is not able to, it sticks to the surfaces. It's,

Jess Kismet (40:09)
Yeah, about 12 mil, yeah.

Joseph (40:28)
There's so much that we know, but we haven't been using simply because things haven't gotten so bad. Well, things are now getting bad and they're now we're having to, well, gee, when was this figured out? Well, in the 1950s.

Yeah, before color television. Yeah, we used to listen to music on these little plastic discs that would rotate at 45 RPM. you know that? Paul McCartney's band before Wings. OK, I know. Elvis Presley, not Elvis Costello. my God, we knew all of this stuff. And now we're having to apply it. the you have two issues. And I'm mumbling here, but.

The issue is how do you do the new stuff? And that's a lot easier than how do I reduce the risk in the existing stuff and save energy in the existing stuff? The existing stuff is way more challenging than the new stuff. And when you do the existing stuff, you want to maintain the beauty, the culture, you know, the joie de vie, the savoir faire, that you don't want it to look like

Jess Kismet (41:20)
Yeah, yeah, yeah.

Joseph (41:43)
You want it to stay and look and maintain beautiful, but you want it to last a long time and save energy and not burn, not be blown away and not make people sick. That's not as easy as some people say.

Jess Kismet (41:54)
I'll see you then.

Okay, two more questions before we finish up. What is the one thing you wish the global construction industry would stop doing immediately?

Joseph (42:10)
venting roofs.

Jess Kismet (42:11)
Right, got it. Alright.

Joseph (42:15)
Look,

don't don't vent the damn frickin roof. You're going to save lives and you're not going to blow off. I mean, come on, stop this.

Jess Kismet (42:22)
Yeah, well,

our bushfires, we have what we call roof blankets and they're insulated foil basically. they're a foil membrane with bulk insulation on the top and we use them in our bushfire zones because that protects the ridge from embers. That's the idea behind it, but it's not vapour permeable. So we have to vent somewhere so air can... mean, the rules around how big the gaps can be around roof venting.

like they have to be no more than two millimetres, which is in inches, I don't know what that is, something very, very small. The gaps can only be two millimetres. So, you know, we've thought of these sorts of things, but we still do have some air that's allowed to go into roof spaces in bushwire zones.

Joseph (42:56)
incredibly small.

Well, but that space is that the reason that that gap is so small is the boundary layer friction starts from a fire perspective and you really don't have much air flow at all. But you still are going to need some means of the little evil moisture molecules are going to get in there anyway. They're just, you know, they just, you know, don't listen to anybody. They end up going to whatever. You need a means of getting them out.

Jess Kismet (43:21)
Mm.

you

Joseph (43:38)
And you need the means of getting them out without having to rely on airflow to do that. So you rely on vapor diffusion. And so you want a layer that's vapor open at some places to allow those molecules of water to get out without having to rely on airflow. Because the airflow is the fire problem. And you all can do it. mean, look, you're... It can be...

Invite me back and spend a little bit more time helping me surf properly.

Jess Kismet (44:15)
you got no hope with me. We do have some nice

beaches in Adelaide if you want to come to Adelaide.

Joseph (44:21)
I could do that. But no, I'm sure there's a lot of approaches that, and your industry is filled with smart, clever people. They really are. And what they need to do is they need to talk to smart, clever people on other sides of the oceans, especially the older ones.

Jess Kismet (44:45)
Yeah, if only we could get the politicians to listen and the housing industry, like the construction industry associations to listen, that would be helpful. Because they keep stopping us from doing better things. There's many sides to that argument and I understand that cost is important and we have a housing crisis. So I understand that.

It's just there are stupid things that we can be fixing that don't have to cost a ton of money.

Joseph (45:18)
Well, let me tell you that you don't have to build everything out of concrete to keep it from blowing away and not burning. We can build out of wood, even though wood burns, we can build out of wood in a way that it doesn't burn. We can use green materials with a low carbon footprint that are normally seemingly not durable, but we can make them durable if we manage the amount of moisture that is absorbed and desorbed. We can do all of these things. It's just that, you know, the

Jess Kismet (45:18)
Anyway.

Mm.

Mm.

Hmm.

Joseph (45:47)
people that are pushing this stuff don't know enough about the material science and the building physics to, you shouldn't listen to them.

Jess Kismet (45:59)
All right, one final question. What is the one thing you want people to know? What is the legacy you would like to leave behind apart from don't vent your roofs? What is the one thing you want people to know?

Joseph (46:15)
In terms of indoor air quality, dilution is not the solution to indoor pollution. Source control is what's necessary. If you build your building out of stupid stuff with materials that are stupid and the materials that go off into your space, it's not very practical and effective.

try to get the materials that are in the air and flush them to the outside by bringing in a whole bunch of clean air. Because a lot of times the outside air isn't as clean as you would want it anyway. And that's the second, that's the biggest problem they're facing now in California with the wildfires is the smoke damage and non-burned buildings. The other thing is that you shouldn't, once you've bought your house, you shouldn't fill the house with stupid stuff that

gives off bad stuff. So don't build out of stupid, smelly stuff and don't fill the house with stupid stuff and don't do stupid stuff in the house that generates contaminants because the amount of air exchange that you're going to need to get rid of that is insanely high compared to not doing stupid stuff. So

Dilution is not the solution and our pollution source control is. And, you know, don't do stupid stuff in your building and don't build it out of stupid stuff. wow, I can't believe that I can make a career out of that.

Jess Kismet (47:59)
So don't do stupid stuff.

Well, I know that the Worldwide Building Science Industry is incredibly grateful for your contributions.

Joseph (48:14)
Well, thank you very much and I'm looking forward to spending time and communicating with all y'all in the coming months and years.

Jess Kismet (48:28)
That would be fantastic. Thank you so much for your time, Joe. Yeah, I hope to talk to you again soon. Thank you.

Joseph (48:34)
You're welcome.