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We changed our roof and cut CO2 emissions

martindaniel.co

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Re: We changed our roof and cut CO2 emissions

#91

Post by Glench »

This is great.

I'd also like to point out that with switching from gas to heat pump heating/cooling you'd probably save even more on your bills and have 0 on-site carbon emissions and likely 0 off-site emissions as your electricity starts coming from non-carbon sources. Heat pumps are around 3x more efficient than the most efficient gas heating because they're just moving heat around, not creating heat.

As Saul Griffith says[0], "You can't 'efficiency' your way to 0" (meaning 0 emissions, which is what we need).

Efficiency is a great win for our bills and cutting some emissions but even if every building made their current systems more efficient, we'd still be on track for over 1.5C of warming. What we need is transformation, and most of that to electric heating/cooling/transport/cooking. And we need it fast, all across the residential and commercial economies in the next 2 decades with more in the next decade. It's going to be a war-time-like effort. Thanks for getting it started!

[0] https://mitpress.mit.edu/books/electrify

Re: We changed our roof and cut CO2 emissions

#92

Post by throw0101a »

mannykannot wrote: post #90
throw0101a wrote: post #68

Earlier quoted context omitted.

> We also put 90mm of external wall insulation round the outside as part of the re-render. This cost an extra £4k compared to just a normal re-render. Having insulation on the outside of your structure, and especially outside of your air/vapour barrier, is ideally where you want it (behind whatever cladding you're using): * https://www.buildingscience.com/documents/insights/bsi-001-t...

This is going off-topic somewhat, but I am thoroughly confused by the article you link to. The author insists we should put the rain control layer inside of the insulation, even on roofs. He does not go into much detail on roofs, but in his wall examples, the outer cladding and the drained cavity behind it appear to be a de-facto rain control barrier outside of the insulation layer (which could be, he says, rock wool…

> If this is so, then what does it mean to say the insulation is outside of the rain control barrier?

Yes, the cladding is acting as a bulk water control layer, but there is still moisture in the air from humidity.

* In a cold climate the warmer/moister inside air will at some point reach the edge of the building: by having the insulation on the outside of the control layer(s), the air will be kept warm, and so there won't be a cold surface for it condense on. If the insulation was on the inside then the control layer would be cold, where the air would condense, possibly causing mold growth.

* In a hot/humid climate the humid outside may get by the insulation and hit the cooler control layer and condense, but will just roll off the control layer outside of the building (and not cause mold inside).

> Furthermore, if we combine these diagrams with the one showing a roof-wall junction, there does not seem to be any barrier against rainwater reaching the wall insulation that way.

This is probably regarding Figure 5. All the various layers are connected to each other, so what's on the inside cannot get out, and what's on the outside cannot get in.

The black line (air/vapour layers) is continuous up the wall, around the corner, and onto the roof. The light blue (insulation) goes continuous up the wall, around the corner, and onto the roof. And the cladding is also continuous so that bulk water and UV rays are also blocked continuously.

See related articles:

> RR-0410: Vapor Barriers and Wall Design

* https://www.buildingscience.com/documents/reports/rr-0410-va...

> BSD-106: Understanding Vapor Barriers

* https://www.buildingscience.com/documents/digests/bsd-106-un...

Re: We changed our roof and cut CO2 emissions

#93

Post by mannykannot »

throw0101a wrote: post #92
mannykannot wrote: post #90

Earlier quoted context omitted.

This is going off-topic somewhat, but I am thoroughly confused by the article you link to. The author insists we should put the rain control layer inside of the insulation, even on roofs. He does not go into much detail on roofs, but in his wall examples, the outer cladding and the drained cavity behind it appear to be a de-facto rain control barrier outside of the insulation layer (which could be, he says, rock wool…

> If this is so, then what does it mean to say the insulation is outside of the rain control barrier? Yes, the cladding is acting as a bulk water control layer, but there is still moisture in the air from humidity. * In a cold climate the warmer/moister inside air will at some point reach the edge of the building: by having the insulation on the outside of the control layer(s), the air will be kept warm, and so there…

That is what I originally thought it might mean, but the article uses the term "rain control barrier", and has a separate item for vapor control.

With regard to their relative placement, see, for example, the caption to figure 2:

"Figure 2: "The Perfect Roof"—The perfect roof is sometime referred to as an “inverted roof” since the rainwater control layer is under the insulation and ballast." [my emphasis.]

The author also writes, in the caption to fig. 1: "The claddings function is principally to act as an ultra-violet screen", thus seeming to differentiate it from any of the control layers he listed at the start of the article.

In addition, the author also lists a separate item for air control, but later writes "What about this air control thing? Well air can carry a lot of water and water is bad for the structure" - further muddying the issue, as now he seems to be discussing water vapor.

I guess this could all be attributed to being sloppy about definitions, to the point of being unambiguously wrong when it comes to roofs.

Re: We changed our roof and cut CO2 emissions

#94

Post by masklinn »

ulzeraj wrote: post #27
pw6hv wrote: post #10

Earlier quoted context omitted.

Actually my experience is the opposite. In colder climates such as Russia, Finland I have seen room temperatures to be quite mild, above 20C for sure. However, in Italy in winter it is quite cold inside. Needless to say that thermal insulation is awful in IT.

I’ve experienced more chilling temperatures in a southern brasilian house during winter than my current apartment in poland. I didn’t even had to turn on heating this winter while in São Paulo I often had to use multiple blankets to sleep. I think that its all about the windows. In warm climate regions they are made to allow air circulation.

> I think that its all about the windows. In warm climate regions they are made to allow air circulation.

Windows, walls, roofs, ceiling heights, …

In warm climates until you have AC you want shade and air circulation / drafts.

Having no roof insulation is not much of an issue (might even be advantageous to trigger forced airflow) as long as you’re far from the roof. Likewise high ceilings keep the heat climbing above head level.

And imperfectly adjusted doors and windows with dodgy (or missing) seals isn’t a bother when it’s not an advantage.

In cold climes none of those is really acceptable unless you want to absolutely nuke your bank account on heating, at least if the house is anything more than a place to sleep in.

Re: We changed our roof and cut CO2 emissions

#95

Post by specialist »

dghughes wrote: post #63
KaiserPro wrote: post #28

One thing to point out is that yes, saving CO2 is grand, but this doesn't sell just how much more _comfortable_ decent insulation makes things. I live in a '30s UK semi detached. It had an air brick , a blocked up fire place and blown double glazing in each room. (barring two that were replaced) We had to re-render the place, as it was starting to fall off at the front, and the back was scarred from unfinished renova…

I wish I had done that to my father's home last year when he was alive. I didn't realize how much heat can come into a home from the attic. The joists act as a heat bridge radiating heat down from the ceiling. I plan on installing fibre wool in two layers one in joist cavities and one perpendicular over the exposed wood frame. My parents also have a door to the attic for storage and heat leaks up through the un-insul…

Am a huge fan of Risinger.

Early on, Risinger did a bunch "building science" explainer videos. Challenging then conventional building practices. Like advanced framing (using 2x6 studs at 24" spacing). Like properly insulate attics to prevent condensation and heat loss (keep HVAC vents within the thermal envelope).

Those early explainers are the foundation (harhar) of subsequent product and project highlights. Alas, now they're hard to find (via YouTube's lame UX). Risinger should probably pin primers to the top of his playlist, linking into his archive.

https://www.youtube.com/c/MattRisinger/videos

Re: We changed our roof and cut CO2 emissions

#96

Post by kingnothing »

danShumway wrote: post #77
KaiserPro wrote: post #28

One thing to point out is that yes, saving CO2 is grand, but this doesn't sell just how much more _comfortable_ decent insulation makes things. I live in a '30s UK semi detached. It had an air brick , a blocked up fire place and blown double glazing in each room. (barring two that were replaced) We had to re-render the place, as it was starting to fall off at the front, and the back was scarred from unfinished renova…

Specifically with insulation, have you had trouble with air exchange? I keep hearing (to my naive/inexperienced/non-builder mind) contradictory advice about how insulated houses should be, and I've been trying to figure out how to square decreasing heating/cooling costs with keeping a house from feeling stuffy. I guess for stuff like the triple glazing that's not really affecting air exchange in the first place, it's…

You can always consider installing an ERV to provide fresh air inside the house with minimal energy loss.

Re: We changed our roof and cut CO2 emissions

#97

Post by lobocinza »

eitland wrote: post #25
blunte wrote: post #15

Earlier quoted context omitted.

I work in temps as low as 5 C and as high as 34 C in this old Dutch house attic. It's not at all pleasant, but there's no upgrading this rented place. It's not worth it for the owner as they will never recover their costs by increased rent. So I wear 3-4 layers, including fingerless gloves and a hat. It looks ridiculous, but nobody sees me. And in summer, well... I don't wear much or anything. I at least put on a shi…

I feel you. Back in 2012 to 2015 I worked most of the time I think in the radio lab at the company I worked for at the time. Temperature was often above 30 degrees in the summer. I didn't think much of it back then, went into office, started working and forgot everything but after a while I realized I was drinking 1.5l water during the work day without needing to visit the restroom and I would be exhausted when I cam…

> Temperature was often above 30 degrees in the summer. I didn't think much of it back then, went into office, started working and forgot everything but after a while I realized I was drinking 1.5l water during the work day without needing to visit the restroom and I would be exhausted when I came home.

These conditions are improper for extended work hours and intellectual work. I don't know how it is on your country but generally there are regulations regarding that. For offices the ideal climate is ~25 degree C, 40-60% humidity and <1m/s wind.

Re: We changed our roof and cut CO2 emissions

#98

Post by throw0101a »

mannykannot wrote: post #93
throw0101a wrote: post #92

Earlier quoted context omitted.

> If this is so, then what does it mean to say the insulation is outside of the rain control barrier? Yes, the cladding is acting as a bulk water control layer, but there is still moisture in the air from humidity. * In a cold climate the warmer/moister inside air will at some point reach the edge of the building: by having the insulation on the outside of the control layer(s), the air will be kept warm, and so there…

That is what I originally thought it might mean, but the article uses the term " rain control barrier", and has a separate item for vapor control. With regard to their relative placement, see, for example, the caption to figure 2: "Figure 2: "The Perfect Roof"—The perfect roof is sometime referred to as an “inverted roof” since the rainwater control layer is under the insulation and ballast." [my emphasis.] The autho…

> The author also writes, in the caption to fig. 1: "The claddings function is principally to act as an ultra-violet screen", thus seeming to differentiate it from any of the control layers he listed at the start of the article.

The cladding can not stop any water and, if the control layers beneath the insulation are properly installed, it won't make any difference. The fact that the cladding does help in blocking rain is just a nice bonus to its primary function.

In some locations it may be difficult for the cladding to do this: think of any place very foggy. There's no way to make the cladding air tight, so high humidity (100%) air will get behind it (stopped by the c. layers). Or if you have shingles on your roof that leak (or get blown off in a storm), they can still block UV, but there will be dripping. And that's why you want the control layer(s) further in.

Water can destroy a structure very quickly if you don't allow for easy/quick drying. Defense in depth.

> In addition, the author also lists a separate item for air control, but later writes "What about this air control thing? Well air can carry a lot of water and water is bad for the structure" - further muddying the issue, as now he seems to be discussing water vapor.

At the top of the article he lists the control layers in order of importance. Controlling for air is more important than control for vapour, as this video explains:

* https://www.youtube.com/watch?v=FXXgjvOJcYI

It's just if you control for air you also just happen to do a lot of controlling for vapour. There's can be a lot of moisture in air, i.e., humidity.

Further there can be some subtleties with moisture/vapour: in many case you want to stop any flow either in or out of the building; in other cases you want to control air but let moisture out:

* https://www.youtube.com/watch?v=zhkGcklWB_Q

* https://www.buildingscience.com/documents/building-science-i...

* https://www.buildingscience.com/documents/insights/bsi-077-c...

Re: We changed our roof and cut CO2 emissions

#99

Post by robomartin »

Interesting.

It would have been nice to add a calculation of the energy required and CO2 produced to manufacture, transport and install that roof.

I feel this is an important metric that is generally ignored in these conversations. And yet, it is crucially important in order to determine the true outcome.

That said, I understand just how complex this input can be to obtain. You can’t reduce it to a number per window. That’s not how it works.

In order for someone to produce those ten (or whatever) windows somewhere in the order of twenty companies must exist and operate constantly. Aluminum mining and processing, steel production, extruders, paint/coatings, chemicals, oil/petroleum, fasteners, cardboard and foam packaging, forklifts, trucks, CNC machines, computers, etc.

The point is: These companies don’t exist just for the 42.5 minutes it took to assemble and pack the windows. In order to be able to buy ten windows, they have to exist whether or not someone is buying that model window or not. The energy required and CO2 produced comes from the combination of all of these factors. And, yes, this is hard to estimate. Yet the numbers are very far from zero.

It’s like saying you are going to go live in a tent on a small island to reduce CO2 emissions while ignoring the car ride, flight and ferry that get you there and the freighter that delivered your possessions.

Re: We changed our roof and cut CO2 emissions

#100

Post by mannykannot »

throw0101a wrote: post #98
mannykannot wrote: post #93

Earlier quoted context omitted.

That is what I originally thought it might mean, but the article uses the term " rain control barrier", and has a separate item for vapor control. With regard to their relative placement, see, for example, the caption to figure 2: "Figure 2: "The Perfect Roof"—The perfect roof is sometime referred to as an “inverted roof” since the rainwater control layer is under the insulation and ballast." [my emphasis.] The autho…

> The author also writes, in the caption to fig. 1: "The claddings function is principally to act as an ultra-violet screen", thus seeming to differentiate it from any of the control layers he listed at the start of the article. The cladding can not stop any water and, if the control layers beneath the insulation are properly installed, it won't make any difference. The fact that the cladding does help in blocking ra…

> The cladding can not stop any water... The fact that the cladding does help in blocking rain...

Clearly you are using some words differently than I do, but it is not clear to me which ones.

>...blocking rain is just a nice bonus to its primary function.

In our house and our neighbor's houses, blocking rainwater is its primary function - we do not live in a desert.

> Or if you have shingles on your roof that leak (or get blown off in a storm), they can still block UV, but there will be dripping. And that's why you want the control layer(s) further in.

And that is when you need to fix your roof, regardless of what is underneath.

In your replies here, you seem to be trying to turn this into a discussion about water vapor, but I have made it very clear that a) my questions are about what the author has to say about rain and water, and b) the author himself makes a distinction between water and vapor control.

Tellingly, you have nothing to say about this quote from the article:

"Figure 2: "The Perfect Roof"—The perfect roof is sometime referred to as an “inverted roof” since the rainwater control layer is under the insulation and ballast." [my emphasis.]

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