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Green Architects' Lounge

An Update on the Pretty Good House — Part 1

A commonsense approach to designing and building a green home

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This episode's cocktail: The Revolver
*2 oz. Bourbon
*1/2 oz. Coffee Liquor
*2 Dashes Blood Orange Bitters
*Orange Zest

Shake with ice, serve in a chilled glass, garnish with orange twist

For many, many more cocktail ideas, browse Fine Cooking's cocktail recipes section.

This episode's cocktail: The Revolver
*2 oz. Bourbon
*1/2 oz. Coffee Liquor
*2 Dashes Blood Orange Bitters
*Orange Zest

Shake with ice, serve in a chilled glass, garnish with orange twist

For many, many more cocktail ideas, browse
Fine Cooking's cocktail recipes section.

Pretty Good House - Graphic Handbook for 21st Century Homes in Maine. By Helen Watts. Concepts so simple, they can be explained in a coloring book. This little book is proving popular in local Lumber yards here in Maine. (At least one has even been shoplifted.)
Image Credit: Helen Watts, P.E.

The status quo of newly constructed homes here in America is, well, disappointing. Despite some strong market-transforming rating systems (such as LEED, Energy Star, Passivhaus, etc.), the classic American home is still being designed and built exactly as it was 20, 30, or even 40 years ago. Why?

There’s a few reasons, the biggest of which is market demand. People buy what’s on the market, and builders build what sells. The only ones pushing the market are those few who are willing to go the extra distance, and do that extra homework to make their projects substantially better. This is actually a very small percentage of those building or buying a new home.

The second biggest reason is that these rating systems often put builders and designers at arm’s length. Let’s be honest: there’s a lot of work involved with these systems. For example, LEED requires substantial fees and administrative work. Passivhaus requires rigorous energy modeling and detailing that sometimes is not the most cost-effective approach (buying $6,000 worth of added insulation to save the amount of energy that one more $400 solar panel would provide, for example). This is where the “Pretty Good House” concept comes into play.

This topic has been covered before here at GBA. (Be sure to check out the links on the sidebar to the left.) But it is an evolving, living concept. The linked articles trace the evolution of the idea and its transformation into a set of guidelines that are still being honed. It’s even become a “coloring book.” That’s right: Helen Watts, a structural engineer who is a regular at our building science discussion group, has put together a graphic handbook.

The concept is still evolving. In this podcast, Phil and I pour ourselves a cocktail and give you an update on where the idea is today.

The Highlights:

Origins: Hear the story of how Dan Kolbert, a builder frustrated with LEED and Passivhaus, simply states, “I just want to build a pretty good house,” and asks the question, “What does that look like?”

What is the Pretty Good House? It’s not a rating system; it’s a set of guidelines.

Considerations: The designer of a pretty good house needs to consider many different issues and may handle each in a way that is right for a particular homeowner. These issues include:

  • Design: Size, orientation, and aesthetics.
  • Climate: Know your climate and design to it.
  • Envelope: Insulation and air-sealing.

We’ll pick up the conversation later in Part 2, when Phil and I will discuss other design considerations such as materials, mechanicals, electrical consumption, verification, and return on investment.

Thanks for listening. Cheers.


Chris: Hey, everybody. Welcome to the Green Architects’ Lounge podcast. I’m your host, Chris Briley.

Phil: And I’m your host, Phil Kaplan. Hi Chris.

Chris: Hi Phil. How’re you doin’, man?

Phil: I am doing excellent this evening.

Chris: Excellent. It’s been a while since we’ve been on the air.

Phil: It’s true. What are we going to talk about today, Chris? I know, but… a little softball for you…

Chris: Thanks. I’m going to try to hit this one. We are going to talk about the “pretty good house.” It’s a phrase that’s become its own thing, and it’s not that well defined out there. Mike Maines has a great blog on it. You can Google it; you can put it in the search bar up there on Green Building Advisor and you’ll get a few hits. But we’ve decided it’s time to really talk about it on our podcast, especially because it was in the New York Times – sort of – within a conversation about Passivhaus.

Phil: Yeah. It was really nice that Martin Holladay – our very own Martin Holladay – was interviewed by the New York Times, and was asked about Passivhaus – I don’t know how the Passivhaus folks feel about it, but… – he talked about Passivhaus and said, “It’s interesting, but not right for everybody…”

Chris: Maybe not the most cost-effective approach…

Phil: “… but you know what is really good? Have you heard of the Pretty Good House?”

Chris: Yeah. And that was a “Wow!” And then (if you were reading the New York Times article online) you click on “Pretty Good House” and – Boom! – it goes to Green Building Advisor and there’s Dan Kolbert at the blackboard at the Maine Green Building Supply, at one of the building science discussion groups that we have here in Maine.

Phil: One of the interesting things about the Pretty Good House is that it’s got this elusive nature that is really kind of wonderful. People have talked about it for a long time, have referenced it – John Straube was talking about it when we interviewed him several episodes ago – and yet, when you look online about “Pretty Good House,” there’s not a lot there.

Chris: That’s right. In fact, its non-defined nature and its elusiveness are probably its best assets.

Phil: Right. Are we going to screw that up and define it?

Chris: Yeah, probably.

Phil: But that’s one of the things you’re working on, isn’t it, Chris?

Chris: When you say, “me” … I’ll let the cat out of the bag: there’s a book in the works. And there’s no one true author. And it might all fall apart and not happen – but, I have a feeling it will. It’s going to pull in a lot of resources and bring in a lot of names of a lot of people that everyone’s heard of and it’s going to have a lot of contributors and no one person’s going to get rich off of this thing. It’s going to be one of those books that’s going to hopefully hit a lot of shelves and act as a reference and a guide.

Phil: It sounds pretty good to me.

Chris: Alright. Well, I hope so.

[The guys jaw about this episode’s cocktail.]

Phil: Tell me about the origins of this.

Chris: Alright, that’s a great start. As many of you know, here in southern Maine we have a building science discussion group. Every month we get together – I know, it sounds boring, but it’s not, it really isn’t.

Phil: It’s a lot of fun.

Chris: It is! There are no name tags – most of us know each other by now; we’re all building professionals. Honestly, there are no clients there, so we’re allowed to make mistakes; we’re allowed to ridicule each other and tease each other. It’s a great atmosphere: there’s food and there’s booze. If clients come, they’re warned, “This is not…” (I’ve had Roger Normand there, he’s a client of mine…) As soon as you have an architect saying, “I know exactly what…” No; no; no. The second you think you know something, that’s when life hands you humble pie. And then you eat it. And then you move on. I’ve had my share.

In one of the discussion groups, Dan Kolbert – who is a builder and the lead moderator (I’m his understudy when he’s not there, so every once in a while I get to moderate) – almost as a joke, he said, “Imagine a builder frustrated with LEED and Passivhaus.” And, like Martin’s comments, “Passivhaus is not for everybody. It’s like summiting a mountain. Not everyone likes to go all the way to the top of Mount Everest – or can. There’s a point at which – I’m going to diverge a little bit, but I think Roger would be fine with this – the Passivhaus that I worked on, we found ourselves spending about a week tweaking windows. We were looking for 6 BTUs per square foot per year. So we were fussing and fussing and moving things around and Marc Rosenbaum just said, “You realize we’re talking about the equivalent of $6 a year in kilowatt hours.” (Maybe I have that wrong, but it was such a small amount.) Wow! One more solar panel, and we could all just shut up and stop!

For the amount he spent on consultants muscling out this last little thing – tweaking the design – he could have bought one more panel and done it. Or not done it, but generate the equivalent amount of energy. It’s that point that Martin always makes about Passivhaus: there’s a certain point where you are no longer doing the most cost-effective thing, but you are doing the purest thing where you are reducing demand – it is the shell; it is energy demand, and that’s what Passivhaus is about, not generation. Alright; small diversion.

So, imagine Dan doing LEED. His house is way greener than a LEED-whatever house. It’s just ultra-green. And it almost feels silly to be working so hard to do the paperwork that you send in to LEED – I’m not bashing LEED. Maybe I am, but…

Phil: Right. There’s this crazy rigor to both LEED and Passivhaus.

Chris: Exactly. And especially, when in the case of LEED: is the paperwork changing your house? Is it modifying it? In this case – no, it’s not. It’s not adding or contributing, it’s just giving you a third-party certification.

Phil: Right. If you’re doing this anyway…

Chris: So, at this particular building science discussion group, he said, “I just want to build a pretty good house. What does a pretty good house look like?” It’s a statement about the status quo. There’s a lot of crap out there, Phil. I don’t know if you’ve gone outside our circle…

Want to learn more about building a pretty good house? Sign up for the Sustainable Building Accelerator and learn directly from author and architect Emily Mottram.

Phil: Yeah, I’ve smelled it.

Chris: Yeah. Phew! Oh man – I mean, you see some of these houses that are being built in some of these subdivisions and you’re like…

Phil: It’s painful! And I want to yell at these people, “Don’t you realize what you’re doing? These houses are going to be obsolete in a few years.”

Chris: Right! “And aren’t you embarrassed?” And it’s not like they’re intentionally going out and… They’re building what sells, and that’s why they’re doing it. People are buying what’s offered – which is that.

Chris: So we started this discussion with, “What should the status quo be? What should a pretty good house be?” And it’s a bit of a trick, because the pretty good house is actually a damn good house.

Phil: It’s a damn good house! Yeah. I remember making the list on the chalkboard. What does that mean, to be “pretty good”?

Chris: It turns out, it needs to be really darned good – a cost-effective bang for the buck, a really good house. I mean, smart!

Phil: Right. “Pretty good”: when I first heard it, it’s got this pejorative smack on it.

Chris: Yeah. I told my wife we’re writing a book, “The Pretty Good House,” and she said, “Well, that doesn’t sound very ambitious at all. You’re setting the bar kind of low, aren’t you? Who’s going to buy that?”

What it is… it’s not really standards; it’s guidelines. When you’re doing a pretty good house, you’re not submitting a checklist in to some third party for certification. This is a way to get everybody on board. Imagine a book or a movement that’s very similar to Sarah Susanka’s…

Phil: “The Not So Big House” – the biggest-selling book of all time for architecture and building.

Chris: Right. And it’s a very simple message, which is: quality, not quantity (Do you really need all that stuff?). And if we focus on details and quality – it’s the same thing, only with energy efficiency – can we do that same thing? And that’s what the pretty good house is.

So, we’re about to take you down the journey about what those guidelines are shaping out to be right now – subject to change as all these experts chime in.

Phil: Wonderful! Take me on that journey, Chris. Where does the journey start?

Chris: Imagine – and in the end, maybe there is a checklist, and – instead of saying, “a pretty good house does these things: Check! Check! Check!” it’s really, “a pretty good house considers these things.” Thermal bridging would be a great example, like, “A pretty good house takes thermal bridging into consideration and does something about it.”

Phil: But it doesn’t get into the level of rigor, per se, and quantify it.

Chris: Exactly. It doesn’t say, “You have to do this or you have to do that.” It’s more like, “If you’re a pretty good house, you’re considering that.”

So, in your checklist, you have three or four things to check off. Maybe you’re wrapping this thing on the outside; maybe you’re doing double studs; maybe you’re doing horizontal strapping. And maybe that’s where the builder, the owner, the architect, somebody writes in what you actually are doing. And maybe it’s clever and better than all those other things and maybe it’s unique to your project – and aren’t you awesome? – and you’re not submitting that to anyone. You’re just – as part of your meetings or something – using that as a guideline as part of the construction process.

And maybe, homeowners out there are going to buy this book. They are going to read it, they’re going to go to their builder and they’re going to say, “Do a pretty good house.”

And the builder’s going to say, “Oh yeah, I know what that is, I’ve heard of that.” And they’re going to be handed this checklist, they’re going to be kind of familiar with it, and they’re going to say, “Yeah, we’re going to address all these things and we’re going to do a good house. A pretty good house. A damn good house.”

So, let’s talk about the guidelines. One: of course, it’s going to be designed. Right, Phil?

Phil: Right. Design is such a broad thing. How do you quantify a pretty good design?

Chris: That’s the hard part. And that’s going to be the hard part of every single one of these things. We’re not going to put a particular thing on it. But you’re going to consider things. There are guidelines. For example: size.

Phil: So, big is bad; small is good. Right?

Chris: Pretty much.

Phil: Right. LEED does that.

Chris: LEED does that, but we’re not going to penalize you because there’s nothing to penalize. There’s just going to be this conversation that you are going to have about it. Look, if you’re a family of two and you have a 6,000-square-foot house, that’s not pretty good. That’s a little wasteful, to be honest. (And if that’s not for you, you’re going to skip over this section.) A pretty good house is not going to do that.

Phil: A responsible professional who talks about a pretty good house is going to talk about these things on this design checklist: “I’ve got it; I’m starting to learn here.”

Chris: Exactly. So there’ll be a chapter in the book where size is going to be one of those things. The same with shape and orientation. There’s going to be a little quick primer about – stuff we’ve talked many times on this podcast: Orienting to the south. Sheltering from the prevailing breezes. Put your living spaces to the south, but your support spaces to the north. Glazing. That sort of thing.

Complexity: keeping your house simple and not doing all of the overly expensive things. That’s not to say you can or can’t. It’s just that a pretty good house is going to recognize complexity as – not necessarily waste, but – something that there’s a premium for.

Phil: Right. You’re making a very clear judgment on a lot of these things. Complexity is not something you want to strive for, period. “I like the look of lots of dormers.” Well, sorry. You can have whatever you want, but that’s not what the pretty good house is all about.

Chris: Right. There may be a dormer. There may be a couple of dormers. You’re considering this thing in terms of “how complex,” and so there will be guidelines about the complexity of your house and keeping things simple.

Likewise, having an integrated design process. I mean, we’ve talked about that. LEED talks about that.

Phil: Right. Bringing everyone on the team on board early and together.

Chris: Right. And having all trades in mind while you’re moving forward. You can’t just plop things in at the last minute and expect it to go smoothly, because someone’s going to have to move a beam to make room for something else.

Phil: Right. So, consider everything.

Chris: Right. And then, of course, one of the things that you’re going to do in design – this is a pretty good house – is actually do an energy audit. “Nah, you’ll be fine. We’ll put a boiler in there; that’ll take care of it. No worries. What are your energy bills going to be? Eh, I don’t know. Whatever.” No. We’re going to have a pretty good idea. And, honestly, you and I do it all the time and it makes sense to us – a lot of times we’re doing Energy Star or we’re doing inspections along the way. It’s part of what we do; it’s actually part of the design in the beginning. And a pretty good house is going to do that.

And then, of course, with the design part, yours and my favorite topic when it comes to green design is: beauty and aesthetics. Because, let’s be honest – an ugly house is not going to last long. Someone’s going to knock it down. There’s a reason why, when you go to these old towns in Europe you say, “Oh man, every single one of these buildings is gorgeous!” That’s because, over a thousand years, the crap gets torn down and the gorgeous things stay.

Phil: Right. It doesn’t matter how energy efficient it is, really. If it’s an eyesore, nobody wants to be near that house, much less in it.

Chris: Right. And likewise, if it’s really not energy efficient, but yet still beautiful and everyone loves it, and functional, it stays and becomes a burden that way.

Phil: Well, one of the other certification systems that’s out there is Living Building Challenge, and they have a “petal” of beauty. And for a while, I’d question that. How are you going to quantify that? But the truth is, it doesn’t matter. Again, they’ve opened up the conversation – and I really respect that – and they make people think about it. It empowers designers to put that on the table.

Chris: It’s important.

Phil: It’s so huge; it’s so huge. And, if anything, it’s such a critical part of the heart of pretty good house, because you can never quantify beauty. You’re not going to try to pin it down. But, you kind of know it when you see it.

Chris: Yeah. That’s the real design part – with a capital “D” – to make sure it’s thought out and not slap-dashed together.

Another big component is climate. You have to know the climate of your house. There are a ton of builders who don’t even know what climate they’re in.

Phil: So you’re saying that pretty good house is going to vary based on the climate that you’re in.

Chris: That’s exactly right. Which means, I can’t write this thing. Right? I’m Mr. Cold Climate. I need people from the South. There are going to be guidelines for every zone. It’s not like there’s anything new in this book or this concept. It’s the way it’s assembled. It’s almost like the Seinfeld episode – this pretty good house is about nothing. Nothing new.

Phil: Have you thought that maybe your wife is right, Chris?

Chris: Yeah. That always happens. Yeah. So for every climate there’s going to be some guidelines in terms of what you should be aiming for. You know how we talk about the 10-20-40-60?

Phil: Yeah. We had somebody write us from Costa Rica at one point. Boy, we are absolutely telling you the wrong thing!

Chris: Exactly. What do we do for you in Costa Rica?

Phil: Please tell us what you do so we can include you as a co-author.

Chris: Yeah. Well, maybe…

And then, of course, in the climate chapter – in the subject of climate – we’ve talked in the building science discussion group about climate change. Does a pretty good house consider our changing climate and what we’re going to be faced with in the future? For example, for us – in the North – we don’t have termites.

Phil: But, they’re moving up this way.

Chris: Are we going to? Probably. We’re probably going to have them. That’s going to be a problem for a lot of the houses that are here, that we’ve built without regard to that insulation that’s just buried and not protected and… Won’t that be curious?

Phil: A big eye-opener.

Chris: Yeah. And then we’re going to have a subject regarding the building envelope. There’s lots to talk about there, and that, in and of itself, is a podcast. There are basic subjects like insulation, Phil. The pretty good house is probably going to follow the same 10-20-40-60 rules, with some numbers becoming less critical as you get warmer.

Phil: Yes, that seems like a good guideline. One of the things I’m interested in, Chris, because we’ve had this conversation… And there are some Passivhaus folks out in the audience. (And you’re one of them too, and I can’t say I’m not, either. I have a foot in multiple camps. We’re doing them as well.) But I, again, wonder where our limits are. And if you ask: if Passivhaus said R-40 walls, are you up to R-60 walls? R-70 walls? R-120 in the roof?

Chris: Yeah. Again, it’s a guideline thing. It’s not going to be right for everybody to do any one particular thing. To say it must be R-60 and you have an R-58, do you fail? No! You did good for what was right for you and your climate and your owner and all of that. What we’re trying to do is elevate that conversation.

But, it’s interesting: we hear a lot of people talk in the Passivhaus camp, saying, “Why are you setting a low bar? The bar should always be just as high as it can be. You should always be striving for that.”

Phil: Right. Because that’s what pushes people. That’s what pushes the envelope further. When you strive to hit 180, maybe you’ll hit 120 when you’re starting at 60.

Chris: Exactly. And that was Jesse’s point when we were talking about that at the NESEA forum. People always feel like they have to choose the middle. If they are choosing the highest part, then they are being the ones who are out there on the cutting edge and all that. And some people spend more because, at least they’re not getting the $24 lobster.

Phil: That’s right. People like the second-most expensive thing on the menu. They’ll never order the first-most expensive thing.

Chris: Exactly right. In a way, the pretty good house. What it’s really doing is, it’s setting the higher bar. It’s recognizing that the status quo right now is really low. And that’s what we talked about in the last discussion group. You leave our circle, you go out into what’s…

Phil: Right. And there’s a lot of production-housing in different parts of the country – and even in the Northeast, for sure.

Chris: Oh yeah. And a lot of it is “meets code, maybe” – which means they’re just not breaking the law.

Phil: And the killer is that this is not affordable housing that we’re talking about.

Chris: No! No. We’re talking about…

Phil: …the standard of what most people would consider high-quality houses.

Chris: Right. Market-rate, custom home design. Well, see… I say “custom” and it gets a little crazy, but… Just a market-rate, newly-built home. I’ll finish up envelope and then we’ll take a break and come back.

With the envelope, of course, there’s insulation and there’s air sealing. We’ll have guidelines for air

sealing. One thing that Passivhaus has really been good for is elevating that. By having a standard for that (0.6 air changes per hour at ach50), it’s gotten a lot of builders and local people here to really start buckling down and trying to at least come close to that. So, there’ll be guidelines in there.

Phil: And, what is that? I remember having this conversation, specifically, and I remember throwing out either 1.5 ach50 or 1.0 ach50.

Chris: Right. Interestingly enough, I think the Maine Housing Authority – or Maine Housing, as they’re called now – they said that if you had 2.5 air changes per hour at ach50, then you had to have an ERV. To you and I, that’s almost humorous. It was like an indoor air quality measure. And so, I think, you and I before, we’d said – and in the building science discussion group, they said – 1.5 is a great number that we should all be shooting for. Shoot for 1! And if you get 1.5, feel good about yourself.

Phil: Right. Every single builder that we’ve introduced this to – that tried to do a tight, superinsulated home – they’ve all hit 1.5.

Chris: Yeah. It’s almost like an awakening where, when builders soak it in and they decide, “We’re going to try and do this. We’re going to try and build this thing tight,” their numbers are amazingly different. And what a difference it makes in the house and in energy performance. I mean, you put that in the model and BAM! Huge difference. Go builders!

Thermal bridging: like I mentioned, if you can minimize the conductivity through your envelope – that’s a guiding principle that you’re going to have to do. A pretty good house is going to actually consider that. So many of these houses out there, they don’t consider it. “Thermal bridging?! What’s that? Oh yeah, we’ll insulate the headers. Done.” There’s more to it than that.

Phil: It’s not enough.

Chris: No. You’re going to have to wrap the outside, or you’re going to have to – we’ve talked about that before – offset: do some double studs, do some horizontal strapping on the inside, or something else clever.

Phil: I really just think you’re on the right track with this. And, I think, once builders see this and are aware of it, I think it’s going to be a matter of pride. Paul Eldrenkamp has been a big advocate, and we’re grateful to have Paul’s backing, because he’s just a wonderful builder and we really respect the guy. When we had the pretty good house presentation at the NESEA annual meeting last year, that was his point. There are a lot of great builders out there, and it’s a matter of pride. They want to do the right thing. You’ve got to show them what the right thing is, and they are going to figure it out.

Chris: And as much as we bash builders every once in a while – I mean, they bash us ten times more than that, but – we have some of the best builders in the world here in Maine. (I mean, in New England.) Honestly, they are top-notch; great; stubborn as hell. Damned Yankees.

Phil: That’s right. Because they’ve been doing it the right way for thirty years and learned from their grandfather.

Chris: Right. Generations. But, boy – once they learn that new way, then that is the thing. Then they’ll be stubborn on that.

One more thing about the envelope and then we’ll take a break. There’s also the roof and radiant barriers and reflectivities of roof. It’s less important here, and that’s a climate thing. For us, the heat island effect in Maine? Not a big deal. In Atlanta – big deal! San Antonio?

Phil: It goes back to your “concentrate on the climate.”

Chris: Right. So, a lot of this is going to matter to you; it’s not going to matter to us. That’s one disadvantage that LEED tends to have.

So, we’re ready to take a break. Let’s refresh these cocktails and get back to this.

Phil: Sounds good.

Chris: Alright.

Part Two is here: An Update on the Pretty Good House — Part 2.


  1. user-1115477 | | #1

    Just an Example of the Two Worlds of Airtightness
    I've been working on a "deep energy" retrofit of my 1983 house for a few years, and added attic insulation before I really had a good idea of how elusive air tightness can be--I only caulked the utility penetrations. I have some can lights in the ceiling. There are two layers of taped-seams polyiso all around the outside of walls, but not where there is brick veneer in the front. Walls are just 2x4 with fiberglass batts.

    I had no idea how the blower door test would turn out (had never even seen one) when the local utility showed up to do it. I was guessing and hoping for 2ach50, from what I had read. When he was doing the test he said, "wow, I have to change the baffle size-I've never seen a house this tight." So, I'm thinking this is cool--I did better than I hoped.

    The house tested at 4ach50.

  2. dankolbert | | #2

    To clarify
    It wasn't "almost as a joke." It was entirely as a joke. Careful what you say.

  3. Christopher Briley | | #3

    Thanks Dan
    Thanks for the clarification, Dan.


  4. ricoball | | #4

    When will the book be published?
    I'm going to be building a house in the spring of 2014. I don't think that I'll get to Passivhaus but PGH is where I want to end up. Eight inches of EPS under the slab, 12" double stud dense pack cellulose walls with 2" EPS and 18" of cellulose in the ceiling. This website has been a godsend to me and would love to have the book in my hands before the design is complete.

  5. Christopher Briley | | #5

    2" EPS?
    The book progress is quite chaotic and no promises can be made at all.

    Sounds like you're building in a cold climate (zone 6?). Is your intention to add the 2" EPS to the outside of your 12" cellulose wall? I question the effectiveness of this (given the added labor and cost). Why not add a bit more to the thickness of the wall? Are you trying to avoid the "cold sheathing" problem?

    I'm just curious. I almost never try to talk someone out of using more insulation.


  6. ricoball | | #6

    Re: 2" EPS
    Yes I am building in Zone 6. Yeah, the recent article here(?) about condensation on the inside of the sheathing spooked me.


  7. Christopher Briley | | #7

    I'd be very interested to
    I'd be very interested to hear other pros on here have to say. On my last passivhaus we contemplated the same thing and opted not to add the EPS. We decided our "excellent detailing" will be enough, and by that, I mean having a well-vented rainscreen behind the siding (3/4" vertical strapping) and tenacious air-sealing of the shell at the sheathing, and at the interior drywall.


  8. skyfarm | | #8

    I am afraid that is not a
    I am afraid that is not a negroni. Gin,campari, and sweet vermouth.

  9. Christopher Briley | | #9

    Wrong cocktail!
    Thanks Chris! I owe you a Negroni. that was our cocktail from last episode this is a 'Revolver.' I'm going to make the change to this post.


  10. GBA Editor
    Martin Holladay | | #10

    Response to Rico Ball
    Thick double-stud walls stay out of the danger zone by drying to the exterior during the months of April and May. They work best if they are equipped with a ventilated rainscreen gap between the sheathing and the siding.

    Here's the principle: the sheathing gets a little damp in February. In April, it dries out. You want to encourage fast drying to the exterior.

    Once you install rigid foam on the exterior of your sheathing, you've greatly limited the ability of the sheathing to dry outward. Now, you are in potential trouble. The damp sheathing will stay damp, and will eventually rot.

    The only way exterior rigid foam will work is if you make it thick enough to keep the sheathing above the dew point during the winter. Then your sheathing will stay warm and dry. Thick foam is good; thin foam is risky.

    If you have a 2x6 wall in Climate Zone 6, your exterior foam needs to have a minimum R-value of R-11.25. (In this case, the R-value of the exterior foam is about 55% of the R-value of the between-the-studs insulation.)

    Once you switch to a 12-inch-thick double stud wall, you have to go to extremely thick foam to stay out of trouble -- in the range of R-24 foam for Zone 6. For an exact calculation of the minimum thickness of exterior rigid foam for a double-stud wall, follow the instructions in this article: Are Dew-Point Calculations Really Necessary?

    One thing is for sure: 2 inches of exterior EPS won't make your wall safer. It will make your wall much more risky.

  11. nuschlah | | #11

    Burning Question from your Local Garage Band
    These podcasts are fantastic, pretty good book idea too, can't wait for it to hit the shelf.

    And I'm sorry to hijack this thread, but I just can't wait to hear your opinion on this question.

    In your Making Green Affordable podcast, you noted that a carport was the most efficient/affordable (sheltered) place to put a car

    But, what if you want a secure and weatherproof place for cars, bikes, extra storage, your drum set, Jerry Rice autograph that your wife won't let you hang over the mantel, or your secret stash of GBA Construction Details?

    Is it a cheaper and more efficient use of materials, labor, energy, to build a separate uninsulated garage structure, or insert a garage into your esthetically pleasing HouseCube (sealed off from the rest of your house).

    (One extra detail, I would think it would be "greenest" (cost, energy, eco, etc.) to not insulate (or very minimally insulate depending on climate) the exterior garage walls of the cube, but air seal and insulate (r40 like an exterior wall) the garage/house "interior" walls.

    Thanks for your help!

  12. GBA Editor
    Martin Holladay | | #12

    Response to John Alden
    The only way to answer your question is to run some cost estimates for different alternatives. In this case, I think that cost is a fairly good proxy for environmental impact.

    Of course, unheated storage is always more green than heated storage. Unheated storage makes sense for bicycles, but not for drywall mud and paint. It's also important consider the need to protect some items from mice.

    If you only have a few items to store, maybe all you need is an extra closet. If you are a real pack-rat, you may need a two-car garage. Run the numbers and find out which option makes the most sense.

  13. Christopher Briley | | #13

    Response to John
    Thanks John,

    Yeah, the garage is one of those structures that by itself, is a luxury to some. Imagine me taking a third world country citizen and showing them, "Look, I have a my own CAR and I keep it in a special building that I've built just for it, AND I even have extra space for my extra stuff." It becomes almost embarrassing. But the reality is that most Americans are very used to having garages, and once you have one, well, it's hard to go back to not having one.

    The truth is that to some people the garage is a "must have" in which case you could treat it in a number of ways.

    1) Detatched is better: The typical garage is a haven for nasty chemicals and VOCs, not just car exhaust but raw gas from lawn equipment, snowblowers, and the like. Not to mention any number of rouge chemicals, (WD40, turpentine, etc.) and spills. The more isolated the garage is from the house, the better.
    2) FROGs Suck: Allison Bailes introduced this term to me “Free Room Over a Garage”. Picture a master suite over the garage. The Garage is probably kept at a lower temperature and might even be completely unheated. That means you’re effectively increasing your envelope to volume ratio by adding a colder space within the house proper. They're going to suck the heat out of the space around them. That’s going to negatively affect your energy profile.
    3) Garage as a buffer: This same idea however can work to your advantage by placing the attached garage to the north or north west. It can buffer the house a bit from the extreme temperatures (especially if it's insulated.) I’ve had clients insulate their garages primarily because a few times a year they might be working on a project out there (with a small wood stove or other point source heater). This garage then becomes an excellent buffer from the extreme cold.

    In terms of cost, it’s like Martin said. It’s best to run some cost options and ask yourself, is protecting my “stuff” worth the extra cost?

  14. nuschlah | | #14

    Response to Martin and Christopher
    Thanks for the responses guys. Some good points to be sure.
    But I kind of like FROGs.


    1. If you insulate and air seal from your home, then I think the buffer benefit is greater than the energy loss. In most instances it's going to be milder than the outdoor temperature, and better to lose some heat to it than the outdoors.

    2. Save at least the cost and material/labor of a roof

    3. plus save 1/2 a foundation (if 2 story FROG), more if its a 3 story frog.

    4. you're saving some siding/waterproofing/sheathing costs (maybe 1/4-3/4 of the cost of a separate garage).

    5. I wouldn't be too dismissive of the benefits of having connected car storage (freezing mornings, rainy nights, etc.). And after all, anything above and beyond a tent and a sleeping bag is all luxury right? Even a pretty good house without a garage is going to look like an embarrassment of riches compared to living conditions of the less fortunate around the world.

    6. Save space (lot / site requirements)

    7. I haven't asked, but I think the wife would be pretty disappointed if she couldn't hear the band as well from the separate garage.


    x. Additional insulation and air-sealing costs (ceiling b/w the garage and the FROG).

    y. I store my VOCs in an outdoor shed. But you would have some car exhaust. Unless you have an elec. vehicle (and a garage would be easier for charging the car, particularly if you're also dealing with solar panel equipment (switch etc.)).

    I also like the idea of fixing the FROG because it is so prevalent, especially for those who don't have the choice b/w separate and internal garages.

    Anyway, sorry for the tangent, and thanks again for the great ideas and discussions!

  15. Phil Kaplan | | #15

    Respons to John Alden
    Hey John-
    Typically, I'd have said that a carport separate from the house is cheapest but I've recently had a builder give me a reality check. Essentially, when an architect starts designing a carport, it gets much more expensive. Of course, when we start exposing the structure, the structure now has to be pretty and so we specify higher-grade materials, do things like get specific about slat spacings, increase post sizes for visual beefiness, etc. Actual attached garages are given less thought, even by architects so the builder can do what he knows how to do, and do it quickly.


  16. Phil Kaplan | | #16

    Martin's response to Rico
    Hey Martin-
    I'm going to challenge the broad stroke made by your comments. We've be looking closely at various wall systems for our BrightBuilt Home line with the help of Robb Aldrich and Bill Zoeller at Steven Winter Associates. Due to cost constraints and line efficiencies, both a double-stud wall and 4" polyiso over 2x6 are not ideal options. However a staggered-stud 2x4 wall on a 2x8 plate with 2" of polyiso is pretty good on many counts. The concern of course is the temp of the surface inboard of that rigid foam within the assembly.

    That's a big concern in general, but if we have an ERV running, we are controlling the humidity levels and reducing the vapor drive through the wall. This will help keep that first condensing surface stay drier and allow more effective drying to the interior. Thank you, psychometric chart!

    They are also finding in their tests that the rot reported has been due primarily to exterior-driven water intrusion, not moisture due to dew point condensation. They're going to be assisting us with some additional modeling on it, but I'm getting more and more comfortable with the 2" exterior rigid.


  17. GBA Editor
    Martin Holladay | | #17

    Response to Phil Kaplan
    I'm conservative when it comes to moisture issues in walls. I'll let you be the guinea pig. We'll revisit this issue again in 10 years. Until then, I'm to stick to my usual guidelines.

    The trouble with wall details that depend on the operation of a mechanical ventilation system for their effectiveness is that houses are sometimes sold, and new owners sometimes forget to operate the ventilation system in the way recommended by the architect.

  18. Mtnlyon | | #18

    you guys are talking about my house
    I have been working on the design of a better house, for a while and hope to build it this starting this spring. I just stumbled onto your podcast and could not believe all the things you were talking about that are the things I have been working on. I am also writing a book on the social justice and environmental justice surrounding modern housing. I can't wait to see your book and hear more from you guys. Keep up the good work.

  19. Phil Kaplan | | #19

    I hear ya', Martin
    One of the big concerns, as you mention, is that we can't predict the habits of future homeowners. We also can't let the Perfect be the enemy of the Pretty Good. Affordable net-zero homes will require some compromise at this point in time. Where that lands and the potential risks and rewards are exactly what we all have to wade into if we're going to get more of these homes built.

    So hand me that guinea pig and I'll try not to kill it.

  20. Mike Steffen | | #20

    Regarding Rico's Wall...
    The concerns about low permeance insulation at the exterior of the wall are understood. As are the concerns about cold sheathing. And yes, as Martin notes, it is highly advisable to be conservative about moisture issues in walls. So...why not take the EPS insulation and change it to high density mineral wool? Now you have a very good wall. Maybe even a great wall. Sheathing stays above dew point almost the entire year, greatly reducing the potential for high moisture in the sheathing. If high moisture content does occur at the sheathing layer it can dry readily to the exterior as well.

  21. GBA Editor
    Martin Holladay | | #21

    Response to Mike Steffen
    If you think that you can install enough mineral wool insulation on the exterior side of OSB or plywood sheathing on a 12-inch-thick double-stud wall to keep the sheathing above the dew point during the winter in Climate Zone 6 -- good luck. Have you done the calculations? I think that you will need about R-24 of exterior insulation, or about 6 inches of mineral wool.

    Perhaps there is a way to build such a wall -- but it won't be cheap, and you'll have all kinds of fastening headaches with such a thick layer of mineral wool.

    I will say this, though: even if you don't achieve your goal of keeping the sheathing above the dew point, at least the mineral wool is vapor permeable. So it's certainly a better choice than thin EPS.

  22. Mike Steffen | | #22

    Response to Martin
    I don't have calcs. I'm one of those guys that you probalby don't want running calcs, esp. WUFI calcs! I guess my thinking was along the lines that if the double stud wall is a good wall but does have some risk of moisture damage due to cold sheathing, then the double stud wall can be improved (i.e. a better wall) with the addition of exterior insulation. Any addition of exterior insulation is going to improve the moisture performance of the wall, as long as the insulation that is added at the exterior is vapor permeable to the degree that it does not inhibit positive drying to the exterior. The more insulation that is added to the exterior, the better the moisture performance of the wall. Rico's idea to add the insulation to the exterior, even if a limited amount, would in fact improve moisture performance, as long as it is a vapor permeable insulation layer.

  23. GBA Editor
    Martin Holladay | | #23

    Response to Mike Steffen
    I agree with your latest post.

    If you are building a 12-inch-thick cellulose-insulated double-stud wall, then a few inches of mineral wool on the exterior side of the sheathing won't keep the sheathing above the dew point in a cold climate. But it will keep the sheathing warmer than it would otherwise be.

  24. STEPHEN SHEEHY | | #24

    garages in a cold climate
    One issue not mentioned above is the desire to get the vehicles out of the way for the snow plow guy and the benefit of not needing to clean the cars after snow. Having lived for decades in MA, NH and now ME, where I finally have a garage, I would never live w/o a garage even if only to avoid the snow related aggravation. Of course, having a place for stuff is nice as well.

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