Insulating materials: organic vs synthetic

[SteamyTea]

18 minutes ago, Garald said:

I am not sure I can keep up, though I am sure that I would learn a great deal by doing so.

Get your university to pay for it, or you will be living in a cabane in the Bois de Fontainebleau.

[Garald]

What do you mean?

[SteamyTea]

7 minutes ago, Garald said:

What do you mean?

Sound all very expensive.

[Garald]

Well, I hope only a fraction of those ideas will be put into practice!

 

[Iceverge]

The core principles remains and unfortunately it's not very sexy.

 

Seal up every tiny pinhole to prevent drafts. I don't know anyone who's ever regretted building a tight house. 

 

Use lots of insulation, in my opinion the "stupider the better" cellulose and mineral wool trump PIR, and aerogel any day for a building. Cheaper and almost complete inert they'll last for centuries without degradation, shrinkage or off-gassing. 

 

MVHR is my one concession to "gadgets" but that is essentially 2 X electric fans and a heat exchanger. 

 

There after a token amount of heating and cooling (if you've been sensible with glazing) will suffice. 

 

 

 

 

 

[Carrerahill]

Just now, Iceverge said:

The core principles remains and unfortunately it's not very sexy.

 

Seal up every tiny pinhole to prevent drafts. I don't know anyone who's ever regretted building a tight house. 

 

Use lots of insulation, in my opinion the "stupider the better" cellulose and mineral wool trump PIR, and aerogel any day for a building. Cheaper and almost complete inert they'll last for centuries without degradation, shrinkage or off-gassing. 

 

MVHR is my one concession to "gadgets" but that is essentially 2 X electric fans and a heat exchanger. 

 

There after a token amount of heating and cooling (if you've been sensible with glazing) will suffice. 

 

 

 

 

 

Sums it up really.

 

During our renovations I carefully sealed up our 60's house, I say carefully because you must ensure ventilation remains to stop Interstitial condensation.

 

By the time I did the extension and pretty much finished it I had created a reasonable level of air-tightness in the living space, the net result was able to be proven through the use of the cooker hood fan to create a negative pressure in the kitchen and then see what sort of airflow there was through the ground floor. I went around and found all the air leaks coming in past rad pipes and things, made note, then filled them all with the relevant sealant. Very very easy house to warm.

 

 

[SimonD]

2 hours ago, Garald said:

I will ask her, but, believe me, I trust her on ventilation. She has lots of ideas that I have barely been following: "ventilation par insufflation" (no idea what the technical term for that is in English) as an alternative to "ventilation mécanique contrôlée"; leaving open the possibility of an adiabatic cooling system; placing ducts under photovoltaic panels to heat air taken in; using the cold air from the quarries which lie somewhere under the building (as in the case in the entire southern third of Paris and immediate environs)...   I am not sure I can keep up, though I am sure that I would learn a great deal by doing so.

 

Your architect sounds amazing and has some very interesting ideas here. Insufflation basically means to blow into something so it is a fan assisted system, possibly a positive pressure system. The drawing of air from ducts under the building could provide you with a very effective natural and low cost summer cooling system - I'm regreting not installing this ducting under my house to feed cool summer air. I assume she's designed some type of vent at the top of the building to create a stack effect to exhaust hot air from this system. I actually have a book published around the mid 1800s that details similar designs. How well the pre-heat system under the the solar panels would be, I'm not so sure.

 

The additional note about the natural insulations is that while you do have the 'scientific' calculations to go by which include decrement delay and moisture transport, the quality of the feel of the indoor environment is so much better with a well designed and installed natural insulation system than one using synthetic materials. IMHO....

[Garald]

14 minutes ago, SimonD said:

The additional note about the natural insulations is that while you do have the 'scientific' calculations to go by which include decrement delay and moisture transport, the quality of the feel of the indoor environment is so much better with a well designed and installed natural insulation system than one using synthetic materials. IMHO....

 

What do you think, then, of the "Solomonic" solution I proposed above - 145mm of natural insulation (Biofib trio) on the southern side (library+piano room; this is where I will presumably spend most of my time), and a thinner (8cm?) layer of phenolic (or what have you) on the northern side (where I have less room to play with)? 145mm is the minimum for obtaining R=3.8 (which is the boundary level for the place being considered well-insulated according to local norms) - it will amount to about 18cm once one adds a fire-proof panel and so forth.

 

Here is a plan of the main (first) floor (left is south-east-south):

 

[Garald]

(The attic is already mostly insulated, except for the side walls and some odd corners. I suppose I'll go phenolic for most of the small chunk of ground floor I have (see my post on another thread; link below) - no idea what I should use for the mini-garage/bike-shed).)

 

[Garald]

Incidentally, do we know enough about the long term effects of phenolic mousse to use it to insulate bedroom walls? If not, a solution may be simply to use a thinner (10cm, say, meaning R=2.65; it would be about 12cm or 13cm once everything is considered) layer of BioFib Trio in the bedroom; a bedroom simply doesn't need to be as warm as other rooms on winter nights, and, since this bedroom faces NWN, it probably won't get all that hot in summer either. (Of course I'd need to see whether having one room with walls at R=2.65 would wreck the energy rating.)

[Garald]

On 06/07/2022 at 23:46, Iceverge said:

 googling double flux = MVHR.

 

Ask her what Airtightness strategy she plans on. 

 

If she has a good plan I think you've got a very good architect. 

 

I was just talking to her over Zoom. Summary (to the best of my ability) on what she said on airtightness:

 

1. Well, of course she has been thinking about airtightness and waterproofing all along. (I'm translating in my head from French; "waterproofing" may not be the right technical term here.)

2. Reasons why we cannot do a perfect job: This is an old building (1930), and a partial renovation project (a pretty thorough one, but it's not as if we were gutting the place; we are even keeping the kitchen and so forth). Brick walls are porous. We need to take into account that they let through not just air but humidity. In the end, it is a matter of controlling air flux and permeability, rather than attempting to forbid the first one entirely.

3. Reasons why people often shoot themselves in the foot while trying to do a perfect job:  if you do not take humidity exchange into account, you end up having either moisture problems inside your walls, or a situation where you end up being told "the insulation job was perfect, now open your windows every day". (Actually, I am living right now in an apartment where the landlady told me to do exactly that - in winter.)

[Garald]

On 07/07/2022 at 15:11, SimonD said:

 

Your architect sounds amazing and has some very interesting ideas here.

 

She was also telling me about a way to supplement heating by means of hot air coming ultimately from the heat pump. (She has given up on the idea of putting ducts under the solar panels.) She's shown me a simple and apparently effective device for doing so:

 

 

https://www.vmi-technologies.com/gamme-vmi/purevent/

 

It also comes with an air filter.

[Garald]

On 07/07/2022 at 00:09, Iceverge said:

Fire hazard, summer heat protection, construction waste, off gassing, thermal looping and high cost are all negatives with phenolic and to a lesser/greater extent with aerogel. 

 

I also talked to my architect about insulation materials. In brief:

 

1. In France, phenolic mousse is used outdoors but never indoors. The reason is presumably that it can emit a lot of gas when heated. She says our contractor would be very reluctant to use it unless perhaps I somehow arranged to get him off the hook for any responsibility.

2. She will read up on aerogel. There do seem to be some French providers, though very few. (Again, the contractor would be loath to use something bought from abroad just like that - for one thing, it would not necessarily come with all the particular technical specifications that he would want or that we might be required to eventually provide.) It's an interesting possibility, particularly for places where we don't have that much space to work with.

3. She's a bit surprised by the negative opinions on https://www.actis-isolation.com/produits/hybris/ - the contractor already installed it at least once, and had had no problems with the product.

4. She was also a bit surprised by the negative opinions on Slimisol Siniat and Isover Isovip (due to their being vacuum packed) - they are apparently well-known products (much less "research-stage" than aerogel) and meet all local regulations.

 

 

[Iceverge]

9 hours ago, Garald said:

1. Well, of course she has been thinking about airtightness and waterproofing all along. (I'm translating in my head from French; "waterproofing" may not be the right technical term here.)

2. Reasons why we cannot do a perfect job: This is an old building (1930), and a partial renovation project (a pretty thorough one, but it's not as if we were gutting the place; we are even keeping the kitchen and so forth). Brick walls are porous. We need to take into account that they let through not just air but humidity. In the end, it is a matter of controlling air flux and permeability, rather than attempting to forbid the first one entirely.

3. Reasons why people often shoot themselves in the foot while trying to do a perfect job:  if you do not take humidity exchange into account, you end up having either moisture problems inside your walls, or a situation where you end up being told "the insulation job was perfect, now open your windows every day". (Actually, I am living right now in an apartment where the landlady told me to do exactly that - in winter.)

 

 

The more I hear the more I think your architect is really clued in. 

 

Three things being talked about here,

1. Breathability (vapour permeability),
2. Airtightness, and
3. Ventilation. 

 

1.  Impermeable internal insulation materials ( phenolic, PIR, polyethene sheets) are a bad idea. They pass the test of interstitial condensation only in theory because you can draw a perfect vapour barrier internal to them. In practice this is impossible. Doubly so on a retrofit.  Every nail and screw (not to mention internal abutting walls and floors) will let humidity into the wall and condense into moisture at the cold side.  Mould and fungus will grow and your old walls will weaken and crumble if the moisture cannot escape. 

 

          Breathable materials like mineral wool, gypsum, woodfiber, cork, hemp lime, clay + intelligent membranes are a far superior and safer option. If moisture gets in it can get out. 

          It's the difference like between wearing goretex and wearing a plastic bag. 

 

2        Airtightness is different. This a continuous layer somewhere into your building that allows no drafts to blow through. It is probably the most important for energy savings and comfort. It is also important to                protect the structure of the building by not allowing humid internal air into the walls as much as possible.  

 

           High quality retrofits like yours will tape/mastic all penetrations diligently back to an airtight but breathable layer of render like clay or lime.  Make a DIY blowerdoor fan to hunt down leaks.  

 

3.        Ventilation. Firstly air for human health . It needs to have appropriate temperature, humidity, free from pollutants, pathogens and excess CO2.   Secondly for the health of buildings, this really is only appropriate humidity. In practice it's only practically achieved by some electric fans running continuously somewhere.  Sucking out, blowing in or both with the added comfort and energy savings of a heat exchanger. Vent holes in the wall only are as practical as a hole in the roof for drinking water, always too much or too little. Opening windows as required doesn't happen in reality.  

 

 

8 hours ago, Garald said:

She was also telling me about a way to supplement heating by means of hot air coming ultimately from the heat pump. (She has given up on the idea of putting ducts under the solar panels.) She's shown me a simple and apparently effective device for doing so:

 

 

 

I looked at the video, it's effectively a PIV (positive input ventilation) module but ducted. It has the advantage of filtering the incoming air but will rely on good airtightness to blow stale air out through the bathrooms. 

 

Given the same constraints and the access to ducting a DCV or MEV would run ducts to the wet rooms and extract the moist air while letting fresh air in through trickle vents or wall vents. Aereco is a French company that has an elegant system of passive humidity controlled inlet vents and humidity controlled fans to only vent to the required level.  It's the most efficient system without using MVHR. 

 

Another alternative is an exhaust air heat pump for DHW like this https://www.atlantic-comfort.com/Water-Heaters/Heat-pump-water-heaters/Explorer, again made in France. 

Whilst not MVHR, it will ensure you're not dumping hot air overboard whilst heating the hot water. @Thedreamer is pleased with his version from Joule. 

 

 

8 hours ago, Garald said:

1. In France, phenolic mousse is used outdoors but never indoors. The reason is presumably that it can emit a lot of gas when heated. She says our contractor would be very reluctant to use it unless perhaps I somehow arranged to get him off the hook for any responsibility.

2. She will read up on aerogel. There do seem to be some French providers, though very few. (Again, the contractor would be loath to use something bought from abroad just like that - for one thing, it would not necessarily come with all the particular technical specifications that he would want or that we might be required to eventually provide.) It's an interesting possibility, particularly for places where we don't have that much space to work with.

3. She's a bit surprised by the negative opinions on https://www.actis-isolation.com/produits/hybris/ - the contractor already installed it at least once, and had had no problems with the product.

4. She was also a bit surprised by the negative opinions on Slimisol Siniat and Isover Isovip (due to their being vacuum packed) - they are apparently well-known products (much less "research-stage" than aerogel) and meet all local regulations.

 

I'm glad to see someone is taking off gassing seriously. When burnt phenolic, PIR and polyurethane are very poisonous.

 

Aerogel for a house can see limited use. For instance upgrading an existing heritage door in a money no object passivhaus refurb. For normal humans to buy in any meaningful quantity it's far too expensive. I found a US store selling Aerogel blankets for $325 for 0.75m2 @ 10mm. To achieve a U value of 0.2 ( 7cm) would cost about €3000/m2.  Mineral wool at 22cm would cost €18/m2 for the same U value. 

 

Vacuum insulated panels are very vulnerable to puncturing, expensive and come with the same breathability issues as plastic board based insulation. 

 

Forget the space age materials is my opinion unless you have NASA's budget.  Just carefully install something breathable everywhere. Maybe 10cm at 0.035w/M2k will be fine. 

  

 

 

TLDR

 

My advice is:

 

A good layer of cheap breathable insulation.

 

Meticulous attention to airtightness.

 

A continuously running mechanical ventilation system.

 

A heat pump. 

 

 

Bon chance! 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Edited July 15, 2022 by Iceverge

[Garald]

3 hours ago, Iceverge said:

 

 

          Breathable materials like mineral wool, gypsum, woodfiber, cork, hemp lime, clay + intelligent membranes are a far superior and safer option. If moisture gets in it can get out. 

 

What _are_ intelligent membranes, and what are their advantages relative to the natural materials you just mentioned? (Feel free to point me to a FAQ.)

 

3 hours ago, Iceverge said:

 

          High quality retrofits like yours will tape/mastic all penetrations diligently back to an airtight but breathable layer of render like clay or lime.  Make a DIY blowerdoor fan to hunt down leaks.  

 

That sounds like something useful - care to elaborate? (Note: I don't have the DIY gene enabled - a link to a good comercial product would be useful.)

 

3 hours ago, Iceverge said:

 

I looked at the video, it's effectively a PIV (positive input ventilation) module but ducted. It has the advantage of filtering the incoming air but will rely on good airtightness to blow stale air out through the bathrooms. 

 

Given the same constraints and the access to ducting a DCV or MEV would run ducts to the wet rooms and extract the moist air while letting fresh air in through trickle vents or wall vents. Aereco is a French company that has an elegant system of passive humidity controlled inlet vents and humidity controlled fans to only vent to the required level.  It's the most efficient system without using MVHR. 

 

Another alternative is an exhaust air heat pump for DHW like this https://www.atlantic-comfort.com/Water-Heaters/Heat-pump-water-heaters/Explorer, again made in France. 

Whilst not MVHR, it will ensure you're not dumping hot air overboard whilst heating the hot water. @Thedreamer is pleased with his version from Joule. 

 

That sounds interesting and I'll read up on it, but I think the architect has got this one down pat.

 

I get the impression from working with her that a good architect is like a good GP:

- there is one thing, their specialty (in her case, ventilation), that they know and understand at a much higher level than you'll ever hope to know,

- they know a bit about many things, and are willing to learn more and discuss what you find out, while also having a solid sense of what works in practice.

 

 

3 hours ago, Iceverge said:

Aerogel for a house can see limited use. For instance upgrading an existing heritage door in a money no object passivhaus refurb. For normal humans to buy in any meaningful quantity it's far too expensive. I found a US store selling Aerogel blankets for $325 for 0.75m2 @ 10mm. To achieve a U value of 0.2 ( 7cm) would cost about €3000/m2.  Mineral wool at 22cm would cost €18/m2 for the same U value. 

 

Vacuum insulated panels are very vulnerable to puncturing, expensive and come with the same breathability issues as plastic board based insulation. 

 

Forget the space age materials is my opinion unless you have NASA's budget. 
 

 

Well, in this nearby suburb of Paris, one m^2 is 6k EUR. (That's presumably in part because it votes Communist - otherwise it would be higher.) Say we are working with 3m ceilings (they are really 2.7m to 2.9m, but they are much higher in the main staircase, obviously). That means then insulating with 10cm rather than 20cm (total, including an air layer on each side) gets you, per m^2 of insulation, a gain of (1/30)th of a m^2, meaning 200 EUR. So that's the maximum difference in price I should be willing to accept for a material that gives me R=3.8 (conventional French boundary value) in 10cm rather than 20cm.

 

 

3 hours ago, Iceverge said:

 

 

Just carefully install something breathable everywhere. Maybe 10cm at 0.035w/M2k will be fine. 
 

 

That's what she was leaning to for the NWN wall, which has the main bedroom/bathroom/wc/staircases. (We'll go for a thicker layer of insulation in the main room, aka library/dining/music room; she's loath to lose space, but I think we can just install shallow made-to-order bookcases, and then use large side panels and create reading nooks in the now large windowsills. The main room faces SES, which is also a two-way street, and so we need as much summer comfort and sound insulation as we can humanly get.)

BIOFIB Trio (which is based on hemp, linen and cotton) is 0.038w/M2K, and seems to have good properties overall:

 

 

 

I still haven't given up on getting something that will have a better performance at 10cm than BIOFIB, at least for the main staircase and also for the wc and bathroom (where we don't have much space to work with). I prefer a cooler bedroom anyhow (if anything, I'm more worried about late-afternoon sun exposure during heatwaves).

As I computed above, a 100-200 eur/m^2 budget would be fully justified, if one can actually get 10cm total, counting air layers.

 

It looks like it will be advisable to get something other than SLIMISOL for les points particuliers, but it looks like aerogel might do (if they are really particular).

 

Right now the place has an E/F rating (probably an F according to the latest standards, properly computed; we got a second diagnostic that confirmed an E/F, but it was made by optimists, or rather people who type things into optimistic software). An average renovation ends up with a D. It looks fairly certain we will get at least a C. Getting a B (which is what optimists predict) is more of a point of pride than anything else - the additional subsidies are minimal (as of now); my architect is skeptical.

 

 

[Garald]

Speaking of being realistic about the fact that a perfect job is not possible in a partial renovation: the (short) eastern wall (which is partly adjacent to a neighbouring building) will remain uninsulated. The kitchen and the small staircase leading to the attic are there - insulating the wall would involve redoing both from scratch (or at least redoing the kitchen and displacing the staircase, though it's unclear that that's possible) and I am not willing to do that for the moment. That will have to wait for stage 2, a few years down the road, when I raise the roof in the attic (currently a place for a home office and low-ceilinged bedrooms - it's above 180cm only in the most central part).

 

 

[Garald]

1 hour ago, Garald said:

 

- there is one thing, their specialty (in her case, ventilation), that they know and understand at a much higher level than you'll ever hope to know,

 

 

Or two things: ventilation and sonic insulation, I believe.

[Garald]

On 06/07/2022 at 17:55, JohnMo said:

>On 06/07/2022 at 10:46, Garald said:

> The architect also mentioned this one before - how does it compare? https://www.actis-isolation.com/produits/hybris/

 

Generally taken on here as snake oil.  You need an unvented air gap either side to get quoted performance, by this point you are taking up as much space as mineral wool, which cheaper.

 

But we are leaving an air gap on either side in any event, for multiple reasons (see the diagram above). Given that that is the case, why would Actis Hybris (an "alveolar isolator") not be worth considering? It is not vacuum-packed, it is not prodigiously expensive (see above for budget considerations), it does not have fume-emitting issues that I know of - and 105mm + air gaps gives an R of 3.8; considered without air gaps, 125mm give R=3.75,  whereas you need 145mm of BIOFIB to get to R=3.8 (interpolating, one can estimate that about 143cm of BIOFIB are necessary for R=3.75). That's a smallish but very real difference. 2cm, in places with nearly 3m height, give you a gain of (0.02/3) m^2 of surface per m^2 of insulation, meaning 40 eur per m^2 of insulation; that would be the price difference that would be justified (assuming that the performance of BIOFIB and Actis Hybris is similar in other respects - that I do not yet know).

 

Perhaps the idea of using BIOFIB on the SWS side and side walls and Actis Hybris on the south wall makes some sense, then - at the very least I would learn more in the long run. (One could of course also do it the other way around - though I'd certainly want BIOFIB on the western side wall: it apparently regulates humidity very well - and the neighbor's garden has vines that climb all the way up that wall, and seem to have affected the humidity of at least part of it.)

 

One would still need to compare other aspects of the performance of BIOFIB and Actis Hybris in wet rooms (WC, bathroom), however; I have those rooms on the NWN side.

Edited July 15, 2022 by Garald

[Garald]

While we are at it: I suppose the Biofib technical specifications in https://www.biofib.com/biofib-trio/ are really about what the Actis brochure (see website above) calls "R intrinsèque"?  If that is the case, and performance increases as for Hybris when one adds air on both sides (as we plan to, in part for soundproofing) then 120mm of Biofib -> intrinsic R = 3.15 -> (R taking air into account)=3.8 or thereabouts. Then 120mm of Biofib (+ air on both sides) should be enough (that's what my architect seemed to prefer the next to last time we talked).

[SteamyTea]

29 minutes ago, Garald said:

R intrinsèque

An important point.

It does not matter how brilliant the insulation properties are on paper, or of paper, if it is fitted badly, incorrectly, or is just unsuitable (water absorbing), then it will not perform as well as expected.

Edited July 15, 2022 by SteamyTea