Robin Jade Conde

PODCAST: Insulating a 1.5-story home

Today we will talk about ways to improve home performance by installing proper insulation.
Tessa shares that there are more ways to insulate a house and discusses how to better insulate and improve home performance. She defines pressure boundaries and thermal boundaries. Bill shares that ”project overcoat” adds years of life expectancy to a 1.5-story house. He explains that having a perfect thermal barrier on the roof and everything below that is conditioned space which will create a very comfortable environment.
Reuben talks about another way to improve insulation, by installing it from the inside of the house; it will create a hot roof where there is no ventilation between the shingles and everything else. He also shares that the color of roof shingles has more effect on the temperature of the roof than ventilation does. Tessa agrees that this is a good method; however, homeowners will lose headspace due to lower ceilings. She also talks about another method to address the insulation by attacking the areas that are physically accessible. Bill shares that the best method is addressing it from the outside.
They talk about the holistic approach and look at a building as an entire system. Tessa highlights that the building performance depends on the design, the materials that are used, how materials are put together, and occupant behavior. She further mentions that the simpler the design is, the better and easier it is to have a high-performing house.
Learn more about Project Overcoat. Visit this link


The following is a transcription from an audio recording. Although the transcription is largely accurate, in some cases it may be slightly incomplete or contain minor inaccuracies due to inaudible passages or transcription errors.

Bill Oelrich: Welcome everyone. You’re listening to Structure Talk, a Structure Tech presentation. My name is Bill Oelrich alongside Tessa Murry and Reuben Saltzman, as always, your three-legged stool coming to you from the Northland, talking all things houses, home inspections, and anything else that’s rattling around in our heads.


BO: Well, two of the three legs of the stool are coming to you from the Northland, [chuckle] but third is possibly in an undisclosed location, several degrees warmer to what? 40-50 degrees warmer than where we’re currently at, Tessa? Probably…

Tessa Murry: We should ask Reuben that question.

BO: Yeah.

TM: Reuben, how warm is it there?

Reuben Saltzman: Yeah. It’s supposed to get up to about 87 today, so I’m in a little better climate, and it gives me the opportunity to get started on just golfing for the year.

BO: Awesome. The never ending winter of 2021, ’22 won’t release its grip from the Northland. We’re gonna top out at maybe 45 degrees, and that’s only relevant to this day, which when this podcast comes out, I’m sure it’ll be much nicer, but…

RS: Oh man, you guys, have we already had this conversation on the podcast? ‘Cause I feel like I’ve talked about this with so many people already this year, but have we talked about the topic of finding things to do in the winter outside to make it short? Have we already talked about that?

TM: Yes. Yes, I believe we have, and we…

RS: Alright, we won’t rehash it.

TM: It’s the only thing that keeps us alive up here.


RS: Yes, yes.

TM: Brainstorming creative activities.

BO: This has… Yeah, and this winter has been a good old fashioned true Minnesota winter where we’ve suffered through snowfall and cold snaps. And it was the yo-yo winter as far as I’ll remember it, because one day it was decent, next day it was cold. One day it was decent, next day it’s cold. Anyway, enough about the Minnesota weather, ’cause God knows, if you talk to somebody from this area, that’s the first thing to ask you about, and it’s the last thing they talk to you about, so. We shall not follow…

RS: And he we are doing it, here we are doing it. We are the worst.

TM: Remember to circle back and close out this podcast talking out the weather, Bill.

BO: Yes, we will do that. Okay. Alright. On to…

RS: Bring it full circle, yeah.

BO: On to more interesting conversation topics. I thought we would go into a recent activity Tessa just did at my house. She was teaching the bright minds of… How would you describe it? The building science department that hails out of the University of Minnesota, our friend Pat Heulman is in charge over there, and Tessa put together a presentation for his class, the diagnostics… Home Diagnostics class. I’ll let you fill in all these details, Tessa, ’cause…

TM: Yeah.

BO: They matter. But anyway, Tessa overtook my house with several bright minds and the gold standard in building science, Pat Heulman, and they spent three hours yesterday just picking apart my house and talking about home inspections and building science and the intersection of those two disciplines. And I thought it was rather interesting, and for once I got a good grade on the work that we’ve done in my old house. So, Tessa, I’m gonna throw it to you. You can explain what the heck was going on yesterday. Apparently, nobody had anything to see because we’ve done a pretty good job.

TM: It’s true, Bill, your house, all things considered was not very interesting to look at, which is actually a good thing if you’re a home inspector…


RS: I’ve said that so many times during inspections of really nice houses like, “Look guys, I’m sorry, this is a boring inspection.”

TM: Yeah.

RS: “It’s good for you, it’s what you want, but I’m kinda bored out of my mind. I got nothing to share with you guys, it’s just a really nice house you’re getting here.”

TM: Yeah. Yeah, yeah. I kept trying to show them things that would be a concern or whatever, and I was talking in hypotheticals the whole time, because you’ve taken such good care of your house, Bill…

BO: Well, not on purpose, it’s mostly because problems showed up and then we fixed them and tried to do it the right way, but…

TM: Yeah.

BO: We didn’t always do that either.

TM: Well, so I do wanna talk about your house more, but we’ll kinda back up for a second. So Pat, people listening to this podcast, they know, he was my professor when I went to the U of M, I graduated in the Building Science program back in 2011. And he reached out to me and was wondering if I could help him with one of his classes for teaching the Building Science students. And I said, “Yeah, sure, what do you want me to do?” And we kinda went back and forth for a while deciding what the class might look like, but we decided on kind of hybrid presentation/home inspection. [chuckle] So he wanted me to go through a house and kind of show them what a home inspection looks like and luckily, Bill, thank you so much, you volunteered your house for this class. And so, we had, I think it was 13 students show up yesterday and they all squeezed into your living room and did the presentation from there. And I think the Building Science program at the U of M is wonderful. It was so long ago that I was in that class, but my memories from it, it’s just kind of like…

TM: It overwhelms you, Pat hits you with with so much information. And it was one of my favorite classes that I took in the Building Science program, because it’s where we really dove into building science and the physics of building science, and it’s the study of heat, air and moisture and how it moves through a house, and that’s really the heart of it, of building science. And at the same time, I remember feeling so overwhelmed because you’re learning all these heat loss calculations and different equations to use, and you just get into the minutia of the science and it’s… I don’t know how I survived that program, because I don’t think of myself as an engineer and it really… It is… That class is really heavy on the math and the science.

BO: What’s the name of the class?

TM: Well, that’s a good question. Residential Building Science? I’d have to ask Pat specifically, it kind of changes… Morphed its name over the years.

BO: Yeah. Was that… He called it a diagnostics class.

TM: Okay, yeah, and I know that he’s kind of got the class broken out into talking about the building envelope first, then looking at mechanicals and talking about mechanicals, and then talking about indoor air quality.

BO: Sounds like a home inspector’s life.

TM: Yeah, yeah, it definitely… There’s a lot of overlap there. And so, I was just honored that Pat reached out to me. And I think one aspect I wanted to kind of show the students yesterday is just give them a real world application of these kind of scientific theories that you hear about in class and you read about in the books and you perform these equations, but what is understanding building science really look like when you’re in a house and how do you use these theories to help you diagnose issues or diagnose potential problems in a house? So that’s what we were trying to do yesterday, and Bill, you gave us a house that doesn’t have any problems.


BO: It has plenty of problems, it’s just… So picture this, you’ve seen this slide before, the story in the half-house where Tessa tries to show where all these thermal boundaries are, and it looks like a geometry picture where there’s lots of angles and triangles and stuff. And our house has all those components, but the way we fixed this heat loss problem… Because when you’re trying to seal up these complicated houses that have vaulted ceilings and intersections, sometimes it’s easier just to go at it from the top and put the closed cells spray foam at the highest point and just let everything below it be conditioned space, and that’s what we did, that ultimately… ‘Cause we didn’t wanna chop up our floor and try to seal up every cavity that could be sealed up. So Tess goes through and she explains all this, and then we went upstairs into my attic and it’s basically, “Okay, we solved that problem this way,” and they could see it first hand. And which was interesting ’cause I asked a lot of good questions, why and how? And so it was fun to see, but Tessa was asking them questions and they were very quiet in the time, and that was funny because he said once he said, “Yeah, we’ve tested on that, so I’m a little surprised that we’re not getting a more robust response to that question.” It’s a lot to take in.

RS: Tessa, you intimidated all of them. Didn’t you?

TM: Maybe I was just talking too fast, I got really excited about the topic of the discussion of the day. But hopefully they were able to grasp some things and there were some good questions along the way, but you know… They talk about in the class, in the building science class, about pressure boundaries and thermal boundaries and why that’s important, and for anyone that’s listening and doesn’t know what that is, it’s basically… The thermal boundary is the insulation layer in a house, so thermal boundaries basically, when you think about it, like the sweater that a house wears to keep it warm. And the pressure boundary is basically another name for it is the air barrier, but it’s the layer that prevents air from moving from conditioned space to unconditioned space. And typically you want that thermal boundary and that pressure boundary to be aligned and touching and continuous through the exterior walls, through the ceiling, all the way down to the ground, because if it’s not, that’s when you get potential problems with warm…

TM: In the cold climate like Minnesota, warm moist air leaking into wall cavities, condensing, creating mold, same thing happens in the attic space, basically, an inefficiency. And it can increase heating cooling costs if you have these discrepancies in your thermal pressure boundary. And it can create mold and moisture problems and lead to durability issues, and it can also lead to subsequently indoor air quality problems if you have mold and deteriorating materials in your wall or in your house, so that’s why those things are really important. And we kind of…

TM: Building science class talks about that, but they don’t get a chance to see that in the field, and so I had some slides of pictures of insulation and a poly vapor barrier on the underside of a roof deck in a story and a half house. So if you can picture kind of the side attic space, like the kind of triangle-shaped attic that’s at the eave area, and a lot of these houses in the twin cities are just… Usually, they’re a mess. We’ve talked about them on the podcast, people know how I feel about story and a half houses, but they’re a challenge to get a consistent and continuous thermal and pressure boundary because of all these different attic configurations, we’ve got the side attic, we’ve got the slant space and usually there’s an upper peak attic too. And so, in these slides that I was showing, they show kind of a variety of how people treat these spaces, and one slide was showing fiberglass batts up underneath the roof deck, also fiberglass batts against the back of the knee wall and fiberglass batts across the floor of the attic. So all three sides, if you can picture it were insulated, and Reuben, you’re shaking your head, but what do we call those spaces?

RS: I’ve been to that house many times. There was a lot of them. And to answer your question, I wanna mess with you Tess and just say it depends, but I know the answer you’re looking for. We call it a confused space. That’s your term.

TM: Yes.

RS: You coined that term for us, and we all use it now.

TM: Well, and I think it’s great because we call it confused because we don’t know, is this space supposed to be inside conditioned space or is it supposed to be outside unconditioned space. We don’t know. If you put the insulation on the roof deck, then in theory, that space should be warm and it should be conditioned, we shouldn’t have any ventilation, attic ventilation, or anything in there, and if the insulation is on the back of the knee wall and the floor, then it should be unconditioned space and it should be attic space with ventilation. And so when you have insulation on all three sides, it’s like, What is this space? It doesn’t know what it is.

RS: And you know what? What I love even more than that is where you’ve got a similar situation, they insulate the heck out of the roof decking.

TM: Yes.

RS: There’s just a ton of it, and then they’ve got holes cut out for every one of the roof vent.

TM: Yes.

RS: Like, what do you doing? Which one is?

TM: Yes, yes you know. That is so funny, I know what you’re talking about, ’cause I’ve seen a bunch of those too. I didn’t include that in my presentation. I’ll do that for next time, but there’s another picture I showed that had a house that had just fibreglass batts on the underside of the roof deck with poly over it, and little tiny holes in the poly from just people hitting it or staples or whatever, and if you look closely, you can see all these dark brown stains from water dripping down the poly. And what would cause that Ruben?

RS: It’s water going through the wood, picking up tannins in the wood, and then depositing that on the poly as the water evaporates.

BO: And why would there be water in that cavity?

RS: You got condensation. It’s not a leak.

BO: Why do you have condensation?

RS: You got warm moist air getting through it, hitting the cold roof decking and condensing…

BO: Oh Pat, oh Patrick… Oh my God, I just called Reuben my son’s name.


BO: Sorry. Reuben, Reuben, come on, why is…

TM: Have you had your coffee yet this morning, Bill?

RS: I heard that, I heard that slip.


TM: So funny.

BO: Why would that be there though, you’re just like all the students yesterday, you’re not giving the right answer to Tessa’s question, she’s digging for more, oh yes she is.

RS: What are you digging for Tess?

BO: It’s the stack effect, that’s why it’s all pushed up there. And those little holes become a thing because there’s pressure boundaries inside this house. And there’s a thermal boundary and a pressure boundary, it’s not just one or the other, it’s both. See, Tessa’s mind is blowing right now, I absorbed so much of this talk yesterday.


TM: You’re gonna teach it next time, Bill.

RS: You know what’s interesting, Bill, that little slip you had, that little Freudian slip, you called me by your son’s name, and it was in a moment when you were getting frustrated with me not getting something that you wanted me to get, is when you did that. I find that so fascinating because…

BO: A true parent.

RS: I will sometime… No, I will sometimes call my friends by my kids names when it’s in a moment where I’m kind of in a mode of giving advice or something like that, or I’m feeling like it’s a fatherly type of relationship that I have with somebody, and I will slip up and I will call them my kids names sometimes. And it’d be Sy if it’s a guy, it’d be Lucy, if it’s a girl. And it’s in the exact same mode that you just did, Bill, I love it.

TM: That’s funny.

BO: One of the funny things about that conversation is through the work that we did on this house, it happened in layers, so we had closed cell spray foam put in our attic space, I made my roof hot so there’s no space unintended on my roof rafters that aren’t filled with closed cell spray foam. But when I did that work originally, we didn’t do the gable ends and we had a break in the vapor barrier at the gable ends, and the winter after getting this really good insulation, I had water pouring out of the gable ends of my house. Not just dripping, literally pouring, every hole in the vinyl siding that was a weep hole just had all this water coming out, and almost perfectly below the unsealed gable end.

BO: And I shared a video with Tessa and she can say that there was a lot of water coming out, and I was like, “Oh my goodness.” So then I hired a contractor… An insulation contractor come back into use closed cell spray foam on the gable walls. And the reason I didn’t do it right away is I was being cheap, and so sometimes you learn your lesson by being cheap, I didn’t wanna tear all that material out at the same time that I tore the other stuff out, it’s like, “That’s finished, I’ll just leave that alone.” But there was an unintended consequence, all that stack effect, and I had this great now…

TM: Pressure boundary and vapor boundary?

BO: I had a pressure boundary and the vapor barrier was perfect, and so there was no place for this vapor to go, it came up and it went out to the side on the gable, and then it just… When the sun came out and would heat up the side of my house, just this water would pour out of it. So anyway, it was… I’ve done this stuff and layers around here, everything that Tessa was teaching yesterday, it’s like, “Yep, we felt that.”

RS: So we’ve talked a lot about a bunch of different ways to screw up the insulation on a one and a half story house. But let’s talk a little bit about what somebody should do, because that’s one of the more common questions we get. A lot of people email in saying, “Hey, I’m about to re-insulate my one and a half story home, what do you think I should do? I’m thinking about doing that… ” People always throw out to me what are they thinking about doing. But what should people do Tess? What’s the best way of doing it?

TM: You know what I’m gonna say? So I’m not even gonna say it ’cause I’m just making…

RS: Tess, stop it, don’t… Yeah. Don’t do it [laughter]

TM: But, there’s more than one way to do it. And so, do you want that space… Do you want a hot roof like Bill did? Did do you wanna use that side attic space for storage? Or do you not care about that? And if you don’t care, you could treat it like most people do, which is like a cold outside space and insulate the back of the knee wall and the floor of the attic. But with these houses, typically what I tell people is, improve the areas that you can improve affordably, so usually that means trying to address the insulation and the air barrier in the side attic spaces. Now, the slant areas are a little bit more difficult typically, because you don’t have access to those slants to insulate them or worry about air sealing, unless you’re gonna rip your ceiling down or take your roof off and hit those spots, and sometimes the peak attic is hard too.

TM: So usually what I’ll tell clients if they’re buying a house like this story and a half house, so first of all, I ask them, Have you ever owned a house like this? And if not, then I try to educate them on some of the challenges that these houses might have with heating, cooling, comfort and ice dams, and then talk to them about trying to improve the side attic spaces. And generally, you can try to add more insulation to the areas that you can physically get to, but you’ll probably still suffer from heat loss and then ice dams still. And so unless you’re going to rip your roof off and fill every single cavity with closed cell spray foam, which is like the highest R value per inch, and then add more insulation over top of the roof deck or fur it down on the inside to basically prevent thermal bridging and heat lost through all the rafters, then you probably still gonna have ice dams…

RS: Wait a minute, Tess. Let me pause ’cause you said fur it down, but I would argue you’re not furring it down, because when I think of furring it down, I think of adding framing on top of framing where you…

TM: Thanks for clarifying that, yeah.

RS: Don’t end up having a thermal boundary. Okay.

TM: Yeah, you’re right, so I should have said you’re basically just installing a rigid form over top of the rafters from the inside or on the exterior to break up that heat loss through the rafters that you’ll get in these story and a half houses, because most of the time, they’re just like a 2 x 4 with sheet rock touching the rafter on the inside and then the roof deck material touching the rafter on the other side, and you just have so much heat loss happening through that wood. And so even if you try to fill that cavity with insulation, a lot of people will dense pack it with cellulose, that’s what they do in the weatherization world, you’re still gonna have all of this heat loss that results in snow melts, which results in potential ice dams. So these houses are a real challenge unless you’re gonna do a ton of work and spend a lot of money on them. And I think for a lot of people, just getting a roof rake or installing really good heat cables is a cost-effective solution to dealing with these ice dams.

RS: Yeah, but can we agree though, that probably the best way of dealing with it is what you just described where you… I mean…

TM: Yeah.

RS: Money is not an issue.

TM: Okay.

RS: You take the roof deck off… We’re not talking about what’s the most economical solution, just what’s the best for performance would be to… If you’re having the roof covering replaced, maybe you have the roof decking removed at the same time. You get a contractor out there who’s gonna spray foam every one of those bays, and then put a layer of insulation down like big sheets, 4 x 8 sheets of foam, like you described, and then put the roof deck in right down on top of that, so you’ve got a thermal breaker. Even better yet, what would be even better than that would be to create an air channel so it’s not truly a hot roof. You actually have like a one-inch gap or maybe even a two-inch gap between the insulation and the roof deck, and there you would frame it up a little bit, you have an air space and then you put shingles on top of that. I mean that would be the absolute best. Correct Tess.

TM: Yeah, you do want an air gap, in a perfect world, you want to try and keep that roof deck cool or colder in the winter time, so it’s obviously not melting snow. And what you described, Reuben, is pretty similar to what we did when I worked… In my previous life at […]doing kinda these home performance upgrades to these story and a half houses and what we do is rip off their roof deck, fill the rafters with a closed cell spray foam, put the roof deck back on, then put two layers of rigid foam on, then basically put sleepers like 1 x pieces of wood on the foam to create that air space and put a secondary roof deck on top of that.

BO: And what you just did is you did something called Project Overcoat and that Pat Heulman did quite a deep dive into that. But what you’ve actually done is you’ve added probably 100 plus years to the life expectancy of a story and a half house in the inner city, and in 2022 when building costs are just extraordinary, if you go all in on a project like this, I believe it’s money well spent. If you’re committed to that size house and you want it to perform well, I think this is a really smart way to attack an expensive environment and get high performance. Now, once you do everything you just described, Tessa, in this Project Overcoat… And we’ll link up a talk that was put out that explains everything in pictures and details, so this is all a very high conversation, but you can see the details of what Tessa is talking about with the sleepers and with the close cell and all of that. But what it does is you have a perfect thermal barrier at the roof, everything below that is conditioned space, once you have that and you have access to mini splits, you can create a super comfortable environment in an old house that’s got tons of charm.

BO: And you can take that house that was going to fall down… Like how many of these story and a half houses do you drive through the city and you see the overhangs are just so fatigued, they’re bending down an inch and a half or two inches because snow has sat there its entire life, it’s just bad anyway, fix all of that in one sitting, put some gutters on to help with your drainage and grading issues that you have, do this in one fell swoop, and boom, you’ve got 100 years of a solid house, and that material that’s in rest of that house is old growth, it’s not going anywhere. It’s like rock solid.

RS: We’ll definitely put that in the show notes, thanks for putting that up, Bill. But just to continue on this topic, let’s go down the line. So we talked about the best way to do it, it’s this Project Overcoat. That’s like… We’ll call that the gold standard. Next, and Tessa, correct me if I’m wrong, but in my mind, I’m thinking what would be next best would be to do kind of as close as you could get to that from the inside of the house, where you’ve got the inside, you take down the existing insulation, the existing wall coverings, you’re down to just rafters exposed and you spray foam the underside of that roof deck in with closed cell spray foam, and then you put big sheets of insulation up to eliminate any thermal boundaries, maybe one inch foam, maybe two inch foam, and then you finish it off from the inside. And at that point you’ve got what’s considered a true hot roof where there is no ventilation between the shingles and everything else, and I will say however we call it a hot roof, but it’s a bit of a misnomer.

RS: I know […] has done studies on the effects of shingle temperature related to the color of the shingles, and as it turns out, the color of your shingles has more effect on the temperature of your roof than ventilation does. Like the difference between a white and a black shingle might be maybe an eight degree temperature difference, whereas venting might lead to about a five-degree temperature difference. Based on that, I’ve never been like live or die by roof vent. I know they’re required by code, shingle manufacturers require them, so you can honor the shingle manufacturer’s warranty, but it’s not a life and death thing. Alright, I’m talking too much.


TM: No, you’re not. No…

RS: Well, I haven’t given you a chance to correct me yet. Well, I’ve gone this far down the path.

TM: Well, ’cause I agree with you, and that is another good method, but a lot of people just hate to lose even more headspace in these story and a half houses, ’cause they’re usually that the ceiling is already really low, and if you’re gonna add more insulation over the rafters, you’re taking even more of that headspace away and people don’t like that, but, yes, that is another option…

BO: Here’s my argument against that. I’ve lived it. And when you tear everything in the inside out, you have to re-finish everything. The trades that are coming into your house, in that project, are painters, they’re drywall people, they’re tapers, and that’s just to get back to a finished product. Plus you have all the rough carpentry, all that other work being done, I’m telling you, go, attack it from the outside, a lot of that is rough work. Shingles are done in a day on a small house.

TM: Yeah.

RS: Yeah.

BO: And there’s nobody […] through your house, I mean… And it’s a better product.

RS: I’ll give you a couple of arguments for doing it, Bill. One would be, if it’s already garbage and you’re gonna redo it.

BO: Sure.

RS: I mean, I’ve talked a little bit about my one and a half story house I used to have in Minneapolis where we… It was just like these tiles that probably contained asbestos and we didn’t test for them, but we took down all these tiles and it was just garbage, and a bunch of it was just these wood panels. It was wood paneling, that super cheap, really dark looking wood, 4 x 8 sheets, I mean, it was just, it was all garbage. So I wasn’t losing anything anyway, that would be one argument for doing it.

RS: Another argument would be, if it’s gonna be a DIY project and you’re gonna be doing it in the dead of winter like, “Alright, it’s November. We’re gonna tackle this project,” I mean, you could get it all done throughout the winter. However, you’re not gonna tear off your roof in the middle of winter and do the spray foam, it’s just… That ain’t gonna work. However, couple of caveats to that. When it’s time to hire the insulation contractor, you’re not gonna have an insulation contractor spraying closed cell spray foam against the roof decking when it’s freezing outside, because it needs to be a certain temperature for the foam to adhere to the roof deck. So that’s one, I know Tessa, you were gonna jump in with that, I stole your thunder, sorry.

TM: No, no, no, you’re getting to the details of this, and I think that’s good for people that are listening, so they understand pros and cons and challenges of doing this. A lot of the times if you’ve got a heated house and just having everything opened up, that that roof decking is gonna be hopefully warm enough for them to spray on it, unless we have a day that’s like minus 20 then they maybe not be able to, but, yeah.

RS: Yeah. Well, and then another word of caution, I did this in the dead of winter, and I wasn’t thinking about how much it was going to drop the temperature in my attic or my half story, whatever you wanna call it, and we had plumbing in the floor. They had roughed in a bathroom up there, and I wasn’t even thinking about that and sure enough, one of those lines burst, and that was one heck of a insurance plan.

TM: What a mess. Oh, man, yeah, ’cause you took all the insulation out and before you got it back in, your pipes froze. That just, that sucks.

RS: Yeah, I didn’t think it actually got that cold up there, but it did.

TM: Yeah, I mean, another argument too that people have for doing it, all this work from the inside, is if their roof is brand new and they just put on a new roof and they don’t wanna trash it. Still a lot of life left.

RS: Yep, yeah.

BO: Well, I think that’s… Now we’re back to your holistic approach, so we really need to look at these things as an entire system. And we kind of went off on a rabbit trail ’cause we do that sometimes, especially when we start talking about building science, because it is what it is, it’s an interesting conversation. Unfortunately, I think the DIYer ends up creating more problems than they solve, and even though they save some money, if you’re not doing it the right way… And I would argue the only way to do this is to attack it from the outside. Like if you truly want a long-term durable solution, I think you attack it from the outside, and you can cut a bunch of holes in your floor to fix every cavity and try to seal it all up, but I don’t know, I like my chances on the outside personally.

RS: Yeah, I like them better too, Bill, I agree with you. We’re just. We’re talking about the next best. But let’s move along on this continuum, so…

BO: There is no next best…

RS: Oh, come on. There’s something else. We talked about gold…

TM: There’s reality.

RS: We talked about silver, what’s bronze?

TM: Bronze is probably what…

RS: What else can somebody do?

TM: I’d say bronze is what I mentioned before, which is attack the areas that you can get to physically…

RS: Okay.

TM: You can get to without ripping everything apart in your house, taking off the roof or taking all the dry wall down, is to attack those areas you can physically get to and make them the best that you can with air sealing in between floor joists, under the knee wall and installing consistent R value across the back knee wall and floor.

RS: Can I pause on that part…

TM: Yeah.

RS: On under the knee wall, just ’cause that is such a huge one, it is so labor-intensive. I mean, that is a massive hole in your air barrier or your thermal boundary…

TM: Both, yeah.

RS: Whatever we wanna call it. And it’s something I think a lot of people don’t think about and they don’t realize how much is involved. What are we talking about under your knee wall, Tess?

TM: Well, if you’re picturing a house and just kind of going down to the skeleton of it, the framing, you’ll have these floor joists, like dimensional lumber that runs usually across the width of the house, and so if you’re peaking your head into the side attic, like through a little door and looking into the side attic space, if you reach down, typically you’ll be able to stick your hand into this empty cavity in between each floor joist. And so you’ve got all these kind of rectangular openings that need to be basically blocked to prevent heat and air movement going from the conditioned space in your house into the side attic space that’s supposed to be cold if you’re putting insulation on the knee wall and the floor. So these are all areas that typically don’t get air-sealed and insulated well because it takes a lot of work, like you said. Someone has to physically… Sometimes you have to remove floor decking, in these side attics to get access to these things.

RS: Oh yeah.

BO: Most of the time you do.

TM: Yeah, most of the time you do, and you have to physically cut… Usually what I see is like a rigid foam installed in between these floor joists, cock it or seal it somehow with canned foam, so you don’t have any or leaking out, but it is very labor-intensive to do, right?

BO: Yeah, you got problems with your attic space one and a half story house. Think about that first, that is a huge hole no matter how much insulation you have, you’re gonna have air moving through it unless you start with that. That would be one of the first things I would focus on.

TM: Yeah, so these houses, we see them as inspectors, all sorts of just challenges that people are constantly battling with frost in the attic or water intrusion from ice dams or comfort issues, people having a separate AC unit in their window to supplement the Foster AC in the house, because those rooms get so hot in the summertime. And so we’re seeing those things when we’re inspecting, but to be able to understand the building science behind these problems, I think, is really, really important and can help us educate homeowners and clients who are buying these houses to know what they’re dealing with, and hopefully help guide them down a path that doesn’t make any of these problems worse and potentially could resolve some of these issues.

TM: So we talked about that yesterday. And along the lines of the pressure and thermal boundaries, I was giving them examples of different houses and what that pressure and thermal boundary could look like and showed them a picture of like a 1950s Rambler and just a simple 5 12 or 4 12 pitch a roof and just a rectangular box, and how if you’re going to try and make a consistent thermal pressure boundary, typically it’s just making sure that that flat attic space that’s accessible is all air sealed and insulated well, and then comparing it to a story and a half house that has all these complicated angles and spaces, and really just focusing on… Building science, really, building performance, I should say, depends on design of the house, and it depends on the materials that are used, and how the materials are put together and occupant behavior, and you can have poor building performance if any one of those things is not done properly or maintained properly or managed, and so design of a house, we talked about just simpler is better. The more simple the roof line, the more simple the thermal pressure boundary is, the easier it is to have a high performance house.

BO: Ruben, I have a new blog for you.

RS: What is it?

BO: We need to give home owners the cheat questions, the cheat cheat questions to ask contractors, when they own these types of properties, how they’re going to attack this solution. So that you know as a homeowner, you’re finding a contractor that’s thoughtful about all of these various issues. “Okay, we’re blending new and old here, how are you gonna make sure that we don’t get a bunch of warm air over here and cause a problem?” and see how the contractor… [chuckle] I think we should give people a pathway to success. And what I learned yesterday is the presentation was X time long and 90% of this presentation was talking about this topic, everything we just covered, and then it’s like, “Oh, by the way, there’s mechanicals in here, there’s electricity in here, there’s other stuff in here and that stuff’s important, but what’s really important is keeping the warm air in here, or keeping the cold air in here, and making sure you have space to get electricity to… ” I think people need to go in armed with questions to ask, not just seeing the finish, they need to see the performance as an important part to this conversation as well.

RS: Well, Bill, that’s a great idea. And as you know, I’m always looking for people on our team to write guest blog posts, [laughter] so I cannot wait for this come out, Bill.

BO: Is that so? Sorry about that.

RS: No, Bill, you’re doing it.

TM: Yeah, I was gonna say buildings are so complex, as we’re talking about this, that it’s almost… It blows my mind trying to think of questions that someone would ask a contractor because you’d have to have a question that represents every single condition that someone might be challenged with, and I don’t know how you do that. But one thing I have thought a lot about is how do you help these homeowners that are struggling with issues or could struggle and don’t even know that they may be creating a non-intended consequence by some of the work they’re doing, and I think really, I see a need for basically building science consultants out there to work with homeowners and to work with contractors, to kind of be that person who understands liabilities and works on preventing them from actually happening and works with the homeowner and bridges that communication gap. So…

BO: I think you start at a high… “If you own this kind of house, these are the concerns you’re going to have. If you’re gonna do construction in this kind of the house, then you need to understand how this works here,” and then reverse engineer some understanding so that when they have that next conversation, they’re like, “Okay, I’ve got a good foundation here.” And then always ask the contractor, What’s the most cost-effective solution, the best, most durable cost-effective solution, because then you go to the gold standard at that point in time, and it’s money well spent that you’re going to capture, in my opinion, qualified by this is my opinion, when you turn around and sell it, you’re gonna get money back on that. When you live in there, you’re gonna say you’re saving money. You know all of this, I think is a win for you, even though it might be more expensive upfront.

TM: I talk to these students about how houses are so complex, you’ve got all these different systems, you’ve got wall systems, roof systems, you’ve got the materials that are used in the wall, and you’ve got mechanical systems and the air quality, and all these different things happening in a house and all these systems are interconnected and they’re dynamic, and you have to understand how they all work together so that you can avoid these unintended consequences. For instance, someone takes an old house and they wanna make it more energy efficient, so they do a lot of insulation and then they do a lot of air sealing as well with that, maybe they replace all their windows, maybe they put on new siding, they do all these things, and their house is a lot more air tight because of that.

TM: So you have to make sure that you are looking at ventilation then in those circumstances to make sure that once you make this old house that used to be leaky a lot more air tight, that you’re not creating moisture problems in the house, the house never used to have those problems and now it could, and so are you looking at installing back fans or a fan in the kitchen, remove those, the moisture and the pollutants. And once you do those things, then are you looking at your mechanical systems to make sure you’re not creating combustion safety issues. Do you have a natural draft water heater that now you’re gonna cause to backtrack? So in my mind, Bill, you blow my mind talking about this cheat sheet, I love the idea and theory of making it simplified, but in my mind, there’s so many systems and when you change one thing you can impact another thing, and so how do you create something easy for a homeowner to navigate themselves?

TM: It’s a challenge, it’s like telling someone that they can go be an MD or a doctor for a human body with a cheat sheet. Like here go see a patient and here’s a sheet for how to handle this rash on your skin, it’s like, Well, is it this is, could it be this, could you treat them with this while it might affect this? Houses need building scientists to diagnose these issues and help guide people through to make them higher performance without creating unintended consequences. Buildings need house doctors just like a human body needs a medical doctor. I think there’s a real need for that knowledge in this world and to simplify it, yes, it’s hard to simplify all these concepts but it can be done, and I think that’s what we’re trying to do with our training program at Structure Tech, is I’m integrating these building science concepts in with the training so that…

TM: You know, inspectors, we need to know a little bit about everything. We need to understand how plumbing works or doesn’t work, and electricity, and siding, and roofing, and mechanical systems, but are we able to put all these things together and understand how they work or don’t work and recognize these potential symptoms of a house that’s teetering on the edge of this cliff, as Pat likes to say? How close to the cliff is the house? Is it close to failing? Is it close to having a major mold issue or combustion safety issue or a durability issue? And basically being able to think holistically when we’re doing a home inspection for where the weak points are in a house and what could be causing problems and where these problems could be happening so that we’re looking for them and we’re educating the potential buyer about them.

BO: Reuben will appreciate this. Yesterday, we had a long conversation about a text I sent him over the weekend. I see this world as a changing world, and why do we do what we do? Well, because that’s what we’ve always done. And I think this industry might be leaning more into what you’re saying, Tessa, and less about finding the problems and more about giving solutions in a way that’s meaningful and affordable, ’cause otherwise… We’re seeing this in the other company Reuben started. Mold testing is going up, people are concerned about it. Why? Well, indoor air quality is a big deal and that’s a whole different conversation. Right? What we do on a daily basis is, “Is this house gonna fall down or not? Is this a good one to buy or not?” which is… It’s clearly a depends answer to that question, but…

TM: Well, and one thing I pointed out to the students that blew their mind yesterday is that, well, number one, there aren’t consistent licensing requirements across states so you don’t have to be licensed to be a home inspector in Minnesota. And then number two, is that our standards of practice that we follow for a home inspection, we follow the ASHI SOP, doesn’t require us to ascribe or identify or disclose the presence of basically health hazards to people like mold or mold-like substances or asbestos or letter, anything like that, and they’re like… Their jaws dropped. They’re like, “Wait, what? A huge portion of building science is understanding air quality and things that could make people sick, and you’re telling me as a home inspector, you’re not looking at that stuff or you’re not reporting on it?” And real world, so many clients, that is their number one concern, it’s mold or something that could make them sick, and here we are, in our industry saying, “We’re not gonna touch it.”

BO: There’s a reason for that, and we’re not gonna go into that now, but I believe, in the bottom of my heart, that what you just described is what people want. And is this house gonna fall down? Probably not and standing there for 75 years so I’m not really concerned about much of this house. What I’m more concerned about is, do you understand what you’re taking on? What are your end goals here? How can we get you there with this house? And here’s how I would attack that.

BO: Alright, we have to put a wrap on this because if we don’t stop talking about this, it could go on for two hours. But I would encourage everybody… We’ll put in the show notes, this Project Overcoat that Patrick Huelman came up with at the University of Minnesota… I’m not even sure if he was at the U of M when they did Project Overcoat, but if you own a story and a half house or a modified two-story where you have vaulted ceilings and the angle in your ceiling before it gets to your attic space, just go watch this. You will learn so much about why this stuff matters. It won’t cost you anything but an hour. And if you’ve got projects in the back of your mind that you’d like to do, watch this first, and then go talk to your contractors about how can you accomplish what you wanna do. Alright, let’s put a wrap on today’s episode, this…

BO: We will continue these conversations ’cause I think all of this is… We’re forward casting or future casting what this business looks like years from now. Thanks for listening, everybody. You’ve been listening to Structure Talk, a Structure Tech presentation. My name is Bill Oelrich, you’ve also heard Tessa Murry, Reuben Saltzman. We are building science geeks at a certain level, we love doing this stuff. So it was a long conversation about building science but as you can tell, it touches a nerve in I think a good way. So thanks for listening, we’ll catch you next time.