vented vs. ventless attics, attic dynamics, architectural efficiency

Unveiling the Truth: Vented vs. Ventless Attics – Performance and Cost Revealed

Foreword by Ian Thompson, Editor

Picture this: Two seasoned builders, Jake Bruton and Matt Risinger, kicking back in an attic, passionately debating about, of all things, attics! You might think, “Why attics?” Well, with the current housing crisis and the rising costs of space, every corner of a house, including attics, are being reconsidered for better utility. Whether used for storage or converted into a functional room, the attic is an important design consideration. The question is, which method is best?

In this video, Jake and Matt dive headfirst into the world of attic ventilation. They question traditional norms and challenge each other’s views. Has attic ventilation become an outdated concept? Has Matt been advocating the wrong approach all this time? All these questions and more are tackled right where it matters the most – in Matt’s very own attic.

This video is a treasure trove of information, not just because of the expertise that Jake and Matt bring to the table, but also because of the casual, free-flowing conversation they share. They’re not just industry experts; they’re friends who love a good-natured debate. Their real-life experiences and lessons learned are shared in a manner that’s more akin to a friendly chat over coffee than a formal lecture.

They explore the intricacies of conditioned attics and delve into the specifics of insulation. Jake shares his approach of building impressive vented attics without compromising on performance. It’s a lively exchange of ideas and practices that offer you a front-row seat to the pros and cons of each system.

So, whether you’re a seasoned builder, an architect, or a curious new home builder, this video is for you. It’s time to join Jake and Matt in the attic for a fresh perspective.

The Great Attic Debate: Conditioned vs. Vented – Which Side Are You On?

We invite you to enjoy the video and keep the conversation going by sharing your thoughts and questions. Let’s learn, debate, and grow together. Now, let’s head to the attic!

Unveiling the Truth: Vented vs. Ventless Attics – Performance and Cost Revealed

Video Transcript

What’s up I’m Jake Bruton and today I have invited Matt Risinger to his own attic so that we can talk about to vent or not to vent and whether or not Matt’s been wrong the whole time. I might have been. We’ll see. We got some good stuff and we might have a less expensive way to get really high performance. We’ll see if I’m wrong or not though. Let’s get going. Jake welcome to my attic my friend.

Thanks buddy. All right you guys, Jake Bruton, builder out of Missouri and Kansas. Jake, I’ve made a video. I’m actually made a lot of videos about conditioned attics. We’re in my attic here. We’re in the air conditioned space of the house.

All my duct work is in this air conditioned space. It also has allowed me uh to put some good storage up here, but I don’t have a basement like you do so in this video I need to maybe write a wrong where I’ve said you can’t do a good vented attic because I’ve actually seen you do some pretty incredible vented attics in the past.

Let’s first walk these guys through this house and how we built this conditioned attic and then I want you to talk us through how you’re doing your vented attics but getting really the same or maybe even better performance from this one. So uh first off, you you were here for a lot of the construction. Tell these guys kind of from your uh eyes how we built this attic.

Well first of all I thank you for inviting me to be in a video where I get to tell you you’re wrong about something. Uh so this is I mean we have to say like this is as good as you’re going to be able to do it right when we talk about you know the insulation choices, the the execution, the the thought and effort that went into your house, your build. There are not very many houses being built in the United States that are disconsidered so I’m going to take that as a compliment. Thank you.

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So we have uh a fibrous insulation on the bottom. We have rock wool. Yep uh what do we have here? We have an R30 uh there R30 bats in between my LVL Rafters. Okay and in climate zone 2 R30 isn’t enough for your attic so you have more insulation.

That’s right but that insulation is on the outside of your air barrier and it’s Imperial like it’s it’s polyiso. It’s it’s impermeable is it Atlas? It’s Atlas polyiso. Okay uh I’ve got 4 in on top of the roof deck and then I added another layer of decking on top of that. Okay so that’s an R20 on top uh it’s a little higher than that it’s like r25 let’s say.

Okay so you have like an r55 assembly with 25 of that being continuous? That’s right uh you have no vents at the eaves because we don’t want any air getting into the assembly. That’s right and you have a Vaper diffusion port at the ridge. Yep uh and I think Vapor diffusion Port is a 2018 in IRC so it’s basically it’s still sealed.

Yep it’s just a vapor open material on the top side because the code and science right recognizes that any moisture migration that gets into this then is going to travel its way upward exactly and then we’ll have a potential for collection up here.

Yep right but but one thing I want to point out that you said that I want to make sure that people understand is there’s no vents in this attic to the outside. This is in effect another room in my house. It just doesn’t have drywall and it doesn’t have necessarily a bunch of AC vents up here. It’s never hotter than maybe 3 or 4° or colder than 3 or 4 de and the rest of the bedrooms which are below us.

Okay so you do or do not have mechanicals end here? I don’t I just have some duct leakage into the space but no specific Mechanicals and behind you on my Erv which is behind us my Zender system I have an extraction uh in out of this attic space so my attic ladder is probably fairly leaky. It’s not an airtight ladder. It’s not an insulated ladder.

It’s a big opening it’s a big opening and that Zender is probably suck in around 20 CFM continuously out of the attic so we never have any stale air up here. That’s right and the fact that we’re not insulated between here and the floor or here in the rooms below they share temperature. Our ducks leak into here and then this is causing de pressurization on the space so it’s pulling HVAC up so exactly. You’re fine to store things up here the same way we would in a basement.

That’s right in effect this is an upside down basement. Yeah this the closet it’s just happens to be above the the bedrooms. That’s right uh so you have storage space you have mechanical space you have all of your uh HVAC lines run through the envelope instead of into an unfinished attic.

That’s all right all my ducks are running up into this space nothing is outside of my envelope and you have access to all of it too. Yep so coming up here to change a filter is a set of steps.

It’s super easy. I mean a set of steps and I’m in a nice air conditioned space drop my filters out of whatever maintain things super easy. However, the one penalty that you spend on this to your point is dollars. Yeah right this is probably the most maybe not the most but this is one of the more expensive ways that you can build.

Now we do have ultimate performance so let’s say where I’m wrong then or where where I think I’ve said in videos we really can’t do a vented attic. Well and let me couch that and then we’re going to talk about how you do vented Attic So one of my big concerns in Texas Jake is that for decades and decades we’ve insulated at the floor line.

Yep we’ve done a pretty poor level of air seiling between the house and the attic and then we put these Flex Ducks everywhere into attics that are our seven ducks and in Texas really throughout the whole South on a summer day it can be 120 to maybe 140 up in that attic.

It’s hot forget about radiant bear decking it’s still hot up there even with all these mitigation practices so now I’ve got ducts with maybe a 60° Delta maybe more between the inside of the duct and the outside of the duct. It’s a recipe for sweating. Uh I’ve never been in an attic that had duct work where I haven’t found mold somewhere on the duct work, on the filters, on the duct board inside the Ducks.

It’s a recipe for disaster and whenever those Ducks leak and they’re going to leak somewhat now I’ve got an air exchange between the outside and the inside so putting ducks out of the condition space and into vented addicts I think in my defense is why I’ve been kind of preaching about how we shouldn’t do vented addicts.

Now let’s fast forward and talk about how Jake does a vented addict because the first time I saw there are people that still put the whole mechanical system in the attic. i’ I we still see air handlers in the attic and it’s like there’s no way you’re insulating that air handler box so that it doesn’t condense.

No so no for sure on the other hand Jake let’s uh let’s think about first off uh let’s go back to Jake did a whole series our first actual follow the build series called the build show build house uh Hilltop Arrow you call it. Yep uh this is a house that had uh uh a bit of a basement, a first floor and then a portion of the house that had a second floor above and I remember specifically going to that second floor INF Framing and thinking where are the interior walls? There’s no interior walls.

Now what talk us through uh how we do this uh vented attic of yours. Yeah so we talked briefly about the the air moving from one layer to the other layer right we want our if we’re going to make all of this outside the envelope then there actually has to be a continuity of the envelope below us so if we’re outside there has to be an air barrier here.

Yep and for that air barrier to be continuous there are certainly ways that you can do it you know drywall or or you know roll barriers or anything but for us that continuity is very easy if we can do it in one big monolithic sheet. Mhm we’re not putting up one big piece of of gypsum in that case. We’re putting up 4 by8 sheets or 4×10 or whatever and then we’re fire taping it before we put up any walls.

That’s right so it’s continuous meaning uh Steve basic is is our architect on quite a bit of our projects and Steve’s really good about knowing how far we can go with our design before we have to have interior partitions that are loadbearing and so we have no load bearing partitions in the majority of the houses that we build. Everything sits on the exterior wall.

There you go so in other words when you walk into that house and you’re in the framing stage that house could be completely framed on the exterior but you wouldn’t have any load coming from an attic through the center or through an interior portion of the house. So in effect it kind of looks like a big barn when you walk in right?

Well actually that’s how I explain it to people because we get push back from time to time like don’t you have to have walls on the inside either from a client or from the comment section you know uh they build barns that are way bigger than that all the time inside.

We’re talking about you know 30t from front to back and then 60 ft long like we’re only spanning 30t you know so it’s it’s very simple in single family residential to engineer a system so that there are no Lo Bing partitions on the inside if you think about it to begin with and then you also need to get your engineer involved.

So for instance uh you know we work with Builder First Source for our trusses uh and instead of using really expensive Rafters or even LVL Rafters like I used here most of your houses are using pretty off-the-shelf uh two by 4 trusses that are probably you know a quarter of the cost of the way I frame this attic right?

Yeah yeah it’s uh and the benefit of doing truss is in our market that the engineering comes with it so we don’t have to have a hire a separate engineer. There are times where we does the trust engineering for you. There are times where we go to permit without even having an engineer on the team because everything is easily explained in the code. I realize that not all houses are like that.

I realize that we live in a very safe space from a design perspective because we work with good team members but there’s like one more cost savings I didn’t you know we pay for the engineering obviously when we pay for the trusses but we didn’t have to have an engineer draw the trusses and then have them verifi to somebody you know it’s there’s some simplicity there that is a real benefit on the cost and front.

That’s right so it starts in some respects with your architect, with your designer, with the person really thinking about the over house making sure that we can design it in a way that there’s not going to be interior load bearing partitions.

So that then here’s the part that I remember the very first time I saw it, it blew my mind. You can hang that drywall on the ceiling in a continuous fashion without any partitions in the way. Yep still in the framing stage there’s no insulation on the walls just on the ceiling and this is before the trades come as well.

And what’s the purpose of that uh? Well you you have better control over what holes you have to fill if they have to make a hole rather than you try to repair a hole it’s a great way to say it. Uh you know if they drill a hole through a top plate that then you have to get to from the top and the bottom and potentially between two plates to seal that’s darn near andoss but if I have a membrane that they have to poke a hole in and I only have to worry about that one membrane it’s fairly simple.

Uh for us a lot of times we’ll have the we’ll chalk lines on our on our Rock to show where the Wall’s going to go anyway you know we just chalk them on the ceiling instead them on the floor and then the electricians or the plumbers or whoever can come in and drill those holes before we frame interior partitions even awesome.

So everything’s there it’s accessible you can roll two layers of scaffolding around and hit everything in a couple hours to air seal everything. Uh with cost effective measures either a can of foam or a little bit of sealant or something like that and then all the framing that happens after that I’m not asking my framers to do air sealing details though.

Yeah and Jake uh if you know Jake you watch his videos you know that he has this phrase one thing for one hole. Y so when his electricians are coming and drilling that they’re knowing hey when I penetrate through that 5/8 sheetrock on the ceiling every time I need to run a wire I put a separate hole in because that way you can seal that on the bottom and the top and know you’ve get a really airtight layer?

What about recessed cans, what do you do about recess cans? Yeah so there are a couple different ways that we do it. If we’re not doing the drywall method we may use like a Sea’s myrex or something uh on the bottom of our trusses and then fur down a Raceway so 2x4s are enough to get uh the pancake cans in. Uh traditional out can lights with the big box they’re they’re kind of not our not our not our cup of tea anymore. Uh they leak a ton of uh air even when they say they don’t. Yeah that airtight can thing is I call BS on that.

So there’s also like we are making some concessions here. Most of the time I would say those those Puck lights have come far enough that they really nobody really notices a difference yeah. Uh and you’re trying to switch the LEDs anyway why are you putting in a fixture that then takes a bulb that it’s separate that you have to buy.

That’s right uh but we have the same problem with bath fans you can’t get away from a bath F potentially we’re building six-sided or five-sided boxes that recess between the trusses.

Uh or one of my project managers was here earlier they have some uh AV Equipment speakers that go throughout the building that they have a little bump between the trusses that the the membrane goes up and and in and then we’ll rock over it and then it’s just drilled the normal hole you would it’s just gen not cutting from here into attic insulation it’s cutting from here into an extended part of the the envelope.

Yep now here’s an important key to this though and it’s the thing that I think gets me so fired up about why I hate vented attics what do you do with that duct work how does that duct work cuz you don’t want that duct work to penetrate out there so what do you do where the heck do you put your HVAC system?

99.9% of the time everything is inside of our our envelope so it’s below the ceiling. Sometimes that’s uh a high wall or a ceiling mounted uh mini split that is ductless uh and our Market we have the benefit of actually having soil so we can have basements. So sometimes things run through the basement.

Uh and then a lot of times especially when we’re working with Steve basic uh Steve’s really good about engineering the house from a standpoint of he knows that duck or has to go to Rooms which some Architects aren’t and he’ll make it so that you transition from say the living room into a hallway that leads to the bedrooms and the ceiling height will be 8 ft instead of 10 ft and then when you go back into the rooms there’s this sense of grandeur when it goes back back up but in actuality you have duck work coming in above your head that just blows into the room now.

So in other words you’ve got this kind of twoot fur down in the hallway, the sheetrock’s already up before the HVAC guy comes so when he puts his duct in and puts that in the hallway he’s able to put it below the sheetrock screw through wherever he needs to into structure into your trusses add that insulation or pardon me add that duct work and now all that’s below the air barrier and none of that this is key none of that’s running through the attic.

Yeah and this is where I think I was wrong but I was also right and I’m eating a little bit of crow here. Uh because I think I’ve said that you can’t have a good vented attic but in fact you can and there’s I think two reasons why you can Jake and I think a big reason why a lot of people are watching this is cost.

Talk to me about the difference in cost between what you see here at my attic? Yeah or even if this was just a basic spray foamed attic versus what you’re doing. Yeah so in our in our systems let’s let’s start with the insulation. We talked kind of first about the insulation here.

Rockwell is a great insulation but it’s not the most cost- effective thing on the market. The poly ISO is the same way. Y uh one of the most cost- effective things you can do is blown in fibergl or blown in cellulose in in my market. Uh that’s most markets not all. Uh there are certainly places where you can get close cell spray foam cheaper than you can get cellulose but they’re few and far between.

So we can get you know your r55 we can get to an r70 for 20% of the cost. Cost probably Max so we’re talking about how many inches of 22 in 24 in and if you need more just blow in a little more. Yeah and you know we have all the space in the world you want to fill whatever you want to fill.

There’s a point where you get very little back on the return once you get to a certain r value but if you wanted to plop r70 up here and do it with cellulose they’re going to do it in a day they’re going to have two people here and it’s going to be an In-N-Out thing and it’ll be pretty darn you know accurate consist.

Yeah uh we we’ll take and on our trusses we’ll put a spray paint Mark you know we’ll shoot a laser and spray paint it so that we can inspect it but we don’t care if there’s 2et of insulation up here because we’re not putting anything up here that people need to be up here for.

That’s right uh I had there’s no service UTI. We don’t do storage if we can avoid it. You know I had a client say well I’d like to put some storage up there and I said so you’d like to carry things up a ladder? I was like, cuz you have a basement that has stairs and actually there a walk out where you could just drive a car around back and he said oh yeah I guess maybe I don’t want to carry everything up there.

I was like cuz anything you carry up there you have to carry back down and your attic in your Market in Missouri could be 0 degrees in the winter and could be 120 in the summer so anything you store up in those attics too is going to get destroyed, my old house had a pair of ski boots I remember I had up there for two or three years, and I went to ski them and they broke all apart ’cause they’d been in in my hot attic for a couple summers.

Yeah, it’s outside. Yeah, you have to remember it’s outside. Uh, the other thing is you’re paying to condition this space like we talked about it as being a good thing because you have storage, you have good access and all that kind of stuff, but you increase the volume of your house by what, 15%? Yeah, so I, you have to take that on account when you do the manual J, and I’ve got additional tonnage on my air conditioner for this additional load.

I also think one of the things that like, if you haven’t figured it out yet we’re kind of saying both work and that both can work. Sure, uh, but I, we had a, I had a conversation with a mutual friend of ours about the McMansion roof that goes all different directions and has nested gable over nested gable over nested gable.

When you have this roofline, this straight gable, it’s very easy to get air flow that’s continuous from there to here. That’s right. When you have these weird trapezoidal things that dead end at, you know, a sidewall or another gable or a nest underneath of another hip, there is no direct path and the opportunity for air to actually move through there.

And what we’re talking about is keep the bottom of the sheathing dry. Yes, that is a real challenge all of a sudden for when we’re looking at like, well, what’s the pathway from there to there ’cause there’s the peak but here’s where it stops, you know.

Um, so trying to build that into something that is, we could say a contemporary roof. A lot of roof lines do look like that in my market still. Uh, they don’t when we build them because we do everything we can to make them simple, more successful.

Uh, so there is a real question mark there where, yeah, we sometimes there are times where we’ve done unvented roofs and that’s uncommon in our market, but I also think that looking what you have and the team that you have in place and the opportunity you have, that kind of dictates what you’re going to say and actually or what you’re going to choose.

And I had, um, Steve Baczek said, um, vent until it doesn’t make any more sense to vent, and I think that’s an amazing way to look at it like, well, okay let’s look at this house and if we’re going to vent this roof, what problems does that cause? Yeah, okay, well maybe not, we’re not going to vent this roof. That’s right, you know. That’s right. So I think there’s a great opportunity for success and a lot of utility in the space that you’ve created here.

And I also think that the way we generally try to do it is cost effective and quick and easy. And I really don’t want to get stuck carrying things into the attic. And it’s really hard to throw a dollar per square foot less metric between this and what you’re talking about, but it’s in the order of, you know, maybe $203- $40-$50 a square foot more that I spent for this style truss system, or pardon me, this style well it is a truss but it’s a man-made truss. Uh, LVL rafters turned into a big open truss with this insulation.

My rooftop insulation monopoly framing – I really did it right but I spent the time and the effort and the forethought to do it. And honestly I spent the dollars to do it. So uh, guys, if you’re not familiar with Jake’s videos, wow I got one surprise for you Tommy. This is cheaper than building a basement though. That’s true. That is a good point. I have soil and I can build basements, but this is cheaper than building a basement. That’s a good point. I hadn’t thought about that.

So you know, yeah, that’s a really good point. And actually one more thing I would say that if you got nothing from this video, the one key you’ve got to implement on your jobs that Jake and I both said in both these different ways, and you’re going to see in all our videos, all of our ductwork is in the conditioned space. It’s inside the air barrier. It’s inside the house so to speak. We don’t want any ducts going outside the house.

So no matter what type you choose, you’ve got to get those ducts. You can’t build Jake’s vented attic that we just talked about and throw a bunch of duct work up there. It’s not going to work. It’s not going to perform the way we’re talking about.

However, if you do it like Jake does it or like I did it, we had very sim, we have very similar blower door scores in fact. Jake’s might even be a little bit lower than some of mine. And really high insulation values and really good results that ultimately lead to a really happy customer, that lead to a really healthy home, a house that’s going to last for generations and not just decades like I see in Texas all the time that drives me crazy.

So pay attention to those details. Bring those ducts into the conditioned space however you do it guys. If you don’t follow Jake currently, go check him out on Instagram, uh @robbuilding.

We’ll put a link to that below. He’s shooting incredible videos on a weekly basis, a bunch of the stuff we referenced and showed as b-roll is videos that he’s already shot including that Build Show build series we’ll put that in the description. But if you’re into building science nerdery like we are and talking about these very specific details, look for the link for Build Show Live which is going to be below. – Jake and I and all our contributors are going to be there. It’s going to be an incredible event in Austin, Texas in 2024 in the fall, November. You got to be there. It’s going to be incredible. There’ll be a link for that below. If you’re not currently a subscriber, hit that subscribe button below. We’ve got new content every Tuesday and every Friday. Follow us on Instagram or Facebook, otherwise we’ll see you next time on the Build Show.

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