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@TechConnectify It’s not only academic, but entirely unrealistic. The only way you could ever find thise R values is if you paid someone to build your house for you.

I can wave a magic wand as well.

@TechConnectify You’re essentially requiring a second structure to be built around the structure simply to hold the insulation. What in the world do yo propose to use as a regular building material with R50?

@transcendentape Blown-in cellulose! That's pretty common and has an R-value around 3 per inch. Create a sea of it in the attic above the celling and once you're above the rafters you can easily be at R-36. Go to 18 inches and you're at R-54.

Code in Illinois is actually R-49 right now.

@TechConnectify You’re hung up on insulation, while I’m trying to tell you that the existence of the unconditioned attic is the problem. Do you think no one in the south has considered insulation?

As you tighten up the building envelope, which is a requirement for efficiency, you exacerbate humidity problems that were previously dealt with by expected losses. Your gut feeling is simply not at all appropriate in my climate.

@TechConnectify From the most basic level, observe where vapor membranes are applied in your climate versus where they are in my climate.

@TechConnectify Now, given the fact that if I am not actively venting my attic, then I can expect it to be at least 50F higher than my conditioned space for maybe five months out of the year. 24/7. That’s not equivalent to outside temperature. And blown in insulation doesn’t have the vapor barrier on the correct side.

There’s a reason different climates have different building norms.

@TechConnectify Actively vent the attic? Why? When nightime temps are above 85F for three months what does actively venting the attic prove? The problem for me, in my climate, is the attic.

@TechConnectify We used to deal with this problem by having twelve foot ceilings and double hung windows and leaky construction with no A/C. Now that we are striving towards efficiency, the attic is the problem, and there’s a good history of home construction to show that attic insulation alone isn’t the solution.

I understand you also have hot days. I’m not talking about hot days. I’m talking about the fact that the lows do not drop below desired temps for months on end.

@TechConnectify Putting the mechanicals in the attic is silly in my eye, but it saves a bit of space in new builds. Putting the ducting in the attic simply makes sense when compared to whatever it is you are advocating. If it is your argument that the ductwork should be in the conditioned space, I agree. There’s a clear advantage to bringing the attic into the conditioned space that exceeds the idiocy of having ductwork inside the living space in my climate.

@transcendentape I feel like you missed some replies in the order I sent them - you seemed surprised by R-49 being code, or at least I pieced that together when I floated R-50 ceiling insulation and you said nobody would do that (or similar).

Regardless, I will grant you that I don't know the fundamentals of combatting moisture well enough to speak intelligently on the subject. However, I still question which approach makes more sense:

@transcendentape Make the attic part of the conditioned envelope, or create a moisture barrier between it and the living space then leave all mechanicals out of it.

Assuming a vapor barrier could be added to the R-50 ceiling insulation that's code here now, then why bother conditioning the attic at all? That's really the crux of my bafflement, and the normality of putting mechanicals up there where you live may cause the less effective thing to be standard due to legacy factors.

@TechConnectify How do you add a vapor barrier above the ceiling in an attic with wooden trusses?

It was almost impossible until a few years ago with closed-cell foam insulation.

@transcendentape I mean, it seems pretty straightforward to me. Simply adding a floor up there to box-in the cellulose insulation ought to work as OSB itself is a vapor barrier. And lots of people do that anyway to make walking around in the attic (and using it for storage) more practical.

@TechConnectify If you think OSB is a vapor barrier, then it’s clear I’ve wasted my time and I’ll bow out until you do the very minimum to educate yourself.

@transcendentape It's listed as an impermeable vapor barrier here:
https://en.wikipedia.org/wiki/Vapor_barrier
And like... I don't see why it wouldn't be! You could use mastic to seal it against the joists if you want to be extra-careful.

But, I'm willing to be wrong.

@TechConnectify I’m not interested in arguing with you any longer. I’ve never seen your house, but I know for a fact that your attic is not sealed with OSB and I think if you gave it half a second to think about why it wouldn’t work, instead of posting a wikipedia article that shows a wall, you would be able to understand why.

You do you, I’m done. Contact home builders or do better google-fu.

@transcendentape I will gladly be done!

I'll just say this - you wanted to know how to prevent moisture from forming on the backside of the colder ceiling drywall. At least, I think that's what you were asking.

Doesn't seem like rocket surgery to me to add an air and vapor barrier above the foot of cellulose insulation on top.

I really think we're talking in circles because how we imagine attics to function is too different.

@TechConnectify Get your ass up into your attic and place a vapor barrier above your blown in insulation with OSB. And when you’re done with that, come on down to Texas and fix all of our other problems as well.

@TechConnectify Maybe I could have made it more obvious, but despite the fact that you clearly don’t have any fucking clue what you’re talking about, it’s easy to insulate a wall. If you insulate the roof deck, it’s almost the same. When you insulate the ceiling, fuck off with your vapor barrier with conventional home building.

@TechConnectify But of course you wouldn’t be expected to know why that’s a problem. You’ve just spent two fucking days arguing it isn’t while I’ve been trying to explain to you why it is. So please, do your homework. I’m done.

@transcendentape Alrighty, I can't help it - you said earlier that it was the act of adding air conditioning that led to mold problems. Is that correct?

It's not simply that the attic is /there/ it's that there is now a place being maintained colder than ambient temperatures near to it.

Now, as far I as can tell, homes here are built like highly-insulated boxes. That box than gets a roof plopped on top of it.

I truly don't know what you mean by "it's easier to insulate a wall"

@TechConnectify No!

Most homes built in my area prior to 1960 or so don’t even have insulation.

The problem is that when you start gunning for cooling efficiency by restricting air movement, then in a hot, humid environment, you’ve got a significantly different set of problems than if you’re trying to keep an area warmer than the outside environment

@transcendentape Okay, we are just on very different wavelengths, then.

I think you might have assumed I've been talking about retrofits and stuff. I'm not - every existing building will face tons of challenges. I've been trying to pick apart new construction differences

No doubt where and how vapor barriers need to be placed varies between where you live and where I live. I can see that very well!

This whole time I've been trying to nail down why new a home built here would be bad down there

@transcendentape And it seems to me that the immense effort we spend to keep heating from escaping /into/ the attic would do just as fine a job at keeping the heat up there from coming back in.

Undoubtedly the details of the vapor barrier would need to change! There's no disagreement there. But you seem to think it would be impossible to adapt the principles of Midwest home design to Southern climates and, well, I don't.

For real, though, let's just end this. It's been nice chatting

@TechConnectify WTF are you arguing? Better insulation in new builds? Guess what, that’s what we’re doing! And the fact that the air handler and the water heater is in the attic has exactly nothing to do with that.

@transcendentape

Oh boy. Let me put it this way.

When I hear you say "you should advocate for making the attic conditioned space" all I can think of is - why? Unless you are going to actively use that space for living, that's more air to heat and cool.

And we're stuck with some circular logic. You say it's fine to put air handling stuff up there, but that only makes sense when that space is conditioned. Which I believed you agreed to early.

I'm saying... just don't.

@TechConnectify This is a perfect example of the difference between our climates. You look at the attic as an unnecessary area to condition, while I look at the attic as a burden to shed.

@transcendentape I agree! And I just want to pick at this one last time:

You had attics before air conditioning, right? Was their existence problematic prior to then?

If yes, then great - ditch 'em! Don't just make them part of the conditioned space, get rid of them entirely and do vaulted ceilings or something.

But if not, I'm left asking how much the mere fact that ducts (which leak) and equipment are up there is contributing vs. the fact that the space below is cool.

@TechConnectify I’m not quite old enough, but I feel confident saying that prior to 1960 or so most homes here weren’t built with insulation or air barriers at all. The common concept was that a structure had to ‘breathe’

@transcendentape OK, so to bring this full circle - we still build our attics to breathe! And moisture is, in fact, the main reason. Plus, we need to minimize ice dams when the snow melts.

The attic is separate - entirely - from the rest of the house. So it's old principles and techniques up in the attic, and new principles down below. Never the twain shall meet.

@transcendentape That barrier for us is mainly thermal. You're right, we don't deal with hot and beastly conditions enough for moisture to be a concern thanks to cooling.

But the barrier is /everything/ and I feel like it could be adapted and perfected in your climate. You'd end up with a very modern structure sitting below a very old-school structure, and (if you ask me) the key to making that work is keeping modern systems and concepts out of the old-school part of the structure.

@TechConnectify It’s remarkable to me that you think you are arguing for keeping modern systems and concepts when in fact you are arguing for precisely the opposite in my case.

@transcendentape It might sound like that, especially from your end, but to me - it's just as baffling to know anyone ever thought the attic is a good place for equipment to go!

And, brass tacks, are the modern concepts where you are born from that norm?

If yes, then from my perspective it's like "y'all took an unideal approach, made that normal, and are now adapting how you do things to fit that norm rather than question the norm"

@transcendentape When we get right down to it, that's where I keep coming back to.

Our disagreement - I think - comes primarily from how attics are used differently. For us, they just... aren't. We don't put stuff up there, they're solely to frame the roof.

For you, they've become a frustrating part of the building system design which you have to battle. And if anything, I'm asking why that battle started. Because perhaps, they say, the winning move is not to play :)

Anywho, I should go

@TechConnectify 1.) I have been irrationally upset with my failure to convey that what I view as obvious is not the same as what you view as obvious. Here’s my restart.

As you know, in the south where the ground doesn’t freeze, there’s no economic reason to have a basement. Many homes are still built with crawl spaces where ducting could be placed, but that building style has seemingly fallen out of favor because slab on grade is cheap and easy.

So, where do the ducts go? In the attic.

@TechConnectify 2. That wasn’t a problem through the 80’s, as homes weren’t air tight enough to matter. This is where our concept of insulation and HVAC functionally diverges due to climate differences. You seem to be worried about heat loss through the ceiling. I want heat loss 3/4 of the year. My problem is humidity. The more efficient the building envelope becomes, the worse humidity becomes unless I am able to exclude ambient air from the structure. That’s easy for me to do in walls

@TechConnectify 3. But it’s very hard for me to do in the attic. Vapor barrier goes on the hot side, and my hot side is my attic for easily 9 months of the year. It is not feasible to install a vapor barrier above insulation in an attic unless you make the roof deck the insulation and vapor barrier and treat it the same as walls. This is, I think, the fundamental difference between building for my climate and building for yours.

@TechConnectify 4. Since the 80’s, we’ve had a problem with the more efficient the building envelope is, the more likely you are to have mold problems. It’s got nothing to do with the ducts, as that would be an easy fix… and including them in the living space would not eliminate the problem. The issue is that for all of at least 3 months and for the majority of 9 months, it is both hotter and more humid outside than is desired inside. Insulation deals with temp, but not the humidity

@TechConnectify 5. The easy way to deal with humidity is to simply be leaky with A/C. That’s the reason why all the old school home builders insist that structures must breathe. But you can’t both be leaky and efficient.

In my climate, eliminating the existence of the unconditioned attic is the most effective way of both increasing cooling efficiency and dealing with humidity.

A hot and dry environment likely has a different ideal construction.

@TechConnectify 6. A cold environment is by definition different, as any leaking incoming air is almost ensured to be drier when heated to desirable temps than the air inside. So yes, you don’t have R50 in your walls, but you might in your ceiling. I also don’t have R50 in my walls because a simple overhang protects my walls from solar load, but R50 in the attic doesn’t fix the problem that I either have a 150F+ attic with a bad vapor barrier or I have an actively vented attic.

@TechConnectify 8. Of course, as you know, wood absorbs water. Imagine each of those trusses acting as a slow wick for thirty years. This is why the attic itself is bad here, and why your insistence that we can insulate our way out of it is both stupid but has been shown to be false for longer than you have been alive.

@transcendentape I'm about to release a video today but before this gets lost in the shuffle I wanted to reply.

Firstly, I understand what you mean and will admit I wasn't considering the nuances of the vapor barrier. However, I still feel like you're missing something.

Granted, what I'm about to suggest may not be "normal" construction. But that's really what I'm trying to do, here! Challenge some norms.

Let's start with a baseline:

@transcendentape The roof has pitch to shed water. That's why it's there, and the negative space creates the attic.

Now, let's agree that we're not using the attic space in any way which truly requires it to be conditioned.

With that in mind, I'd like to circle back to your assertion that it's easy to insulate a wall, but harder the ceiling. What if you simply built the ceiling like a wall? Like a really thick wall. Same techniques, but sitting on top of the other walls making a big box.

@transcendentape Not just some drywall with cellulose on top, but a proper enclosure with sufficient vapor barrier. Like a home with a flat roof.

Flat roofs are cool, but also have some downsides so you decide to put a hat on this flat-roofed house and that's now the attic.

Do we agree that that sort of home could be built? I'm not making any conjecture about cost-effectiveness, here - just that it could be done in your climate.

@transcendentape Because if the answer is yes, I question the value of conditioning that attic space at all. It's a lot more air volume, the insulation will be in direct contact with the hot AF roof structure, and surely those factors increase the total thermal load.

And if you add forced ventilation to that attic space when the sun's up, you'll decrease the temperature gradient the insulation is fighting against.

@transcendentape Treating the attic solely as a structure to frame the roof, letting it breathe, and keeping it entirely thermally (and... vaporly?) separated from the conditioned part of the structure doesn't seem any different to me than the realities prior to the advent of cooling. You just have old-tech above the living space and new-tech within it.

But, I'll grant you right out of the gate that there may very well be other factors I'm not considering.