Talk:Building insulation materials

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I am currently creating a page with information exclusively about cellulose insulation. I am interested in the history of the regulation of insulation. From what I have read and researched, (mostly involving reading federal government documents of committee meetings and a few mentions in books printed around that time) it begins to seem like fiberglass manufacturers benefited from regulations and building codes while cellulose manufacturers got nailed with regulatory burdens. It isn't totally clear to me that the claims of cellulose insulation fires were ever above ordinary as compared to fires beginning in the walls or attic of an uninsulated wood frame house or as compared to fires in a fiberglass insulated house. Recent studies even suggest that cellulose helps protect a home from fires while fiber glass allows increased oxygen to fires making them worse. I guess my main question is whether small time cellulose manufacturers were particularly crummy in their quality standards back then or if the whole thing was a Public Relations nightmare spurred by fiberglass interests trying to shut down the competition.--Bwildleaf 00:35, 7 March 2007 (UTC)

Glad you did this, Bwildleaf. I was planning on doing the same after researching Cellulose and other options endlessly. I was surprised by the lack of good info both here and in other Web sources. I've added a good amount and will add more now that I finished installing cellulose (it beat the other options hands down). When it comes to your question on past bias, it seems from my reading that both are true - there was unsafe use of cellulose that allowed fire, plus a fiberglass industry that won through influence. The new cellulose options are substantially different than those old options. --Alphastream (talk) 03:17, 17 March 2008 (UTC)



In regards to section 11 (safety issues, cellulose materials), how are the last two bullets relevant to the topic of loose-fill cellulose in 11.2?It states "Although cellulose is 100% natural, and usually made from recycled material, loose-fill cellulose is not as environmentally-friendly as some people would have you believe." The final two points under this statement, if anything, seem to read as positive points about cellulose's environmental friendliness (not negative points as the initial statement implies). If cellulose isn't susceptible to mold, then aren't the final two points contradictary to the initial statement above the three bullets? Ricojonah 13:25, 26 August 2007 (UTC)

I believed this to be author bias. In reviewing the literature, while the level of mold protection can be somewhat argued, the overall environmental benefits of cellulose are very high. --Alphastream (talk) 03:17, 17 March 2008 (UTC)


Contents

[edit] Radiant barriers

There are a lot of myths about radiant barriers. The section here seemed to repeat some of them; whereas the article on radiant barriers is pretty much free of them. I removed some of the myth-influences stuff from here, while resisting the temptation to explain it more fully, because the main radiant barriers page is the right place for that. If you like some of what I removed, I suggest adding it back to the radiant barriers article, where that can be debated and developed more fully.Ccrrccrr 23:05, 7 November 2007 (UTC)

[edit] Spray foam disadvantages

There appeared to be a minor edit war going on, with two anonymous parties deleting each others contributions in this section, while both also added value. I attempted to construct a best-of-both edit. If I did some thing wrong, please discuss here.

I replaced specific R-value and cost numbers with more general statements. I would welcome quantitative data there if reliable sources are cited.

I restored the information on toxic fumes in combustion, HCFCs (added some info there), and solvent and sunlight protection. Ccrrccrr 19:03, 30 November 2007 (UTC)

The R-value (insulation) page has R-Values. If you find other sources, please add there. --Alphastream (talk) 03:17, 17 March 2008 (UTC)

[edit] Spray foam advantages

There was a line saying "* Can fill wall cavities in finished walls without tearing the walls apart (like loose-fill).". Everything I see suggests that you use a similar sized entrance hole to insert the foam or fill. Granted, I'm thinking cellulose here (video is available at This Old House of the installation) but it seems likely that the same is true for other loose fill. Therefore, I changed the parenthetical to refer to batts, since those do require removing the wall to re-insulate. If someone sees it otherwise, please change and cite.

I suspect the "like loose fill" mean to refer to "can fill wall cavities without" not to "tearing the walls apart". In other words, I think you agree with whoever wrote it originally, but obviously the wording wasn't very good or clear. Probably still needs clarification.Ccrrccrr (talk) 12:07, 17 March 2008 (UTC)

Similarly, there was a statement "* Expands while curing, filling bypasses, and providing excellent resistance to air infiltration (unlike batts, blankets, and most types of loose-fill, which can leave bypasses and air pockets).". Everything I have read suggests that loose fill, and especially wet or semi-wet cellulose, do a very good job of filling against infiltration. While spray foam is likely superior, the statement (and perhaps the section) seemed to denigrate loose-fill more than it should. I changed the wording to "(unlike batts and blankets, which can leave bypasses and air pockets, and superior to some types of loose-fill)". Please change and cite if you see it otherwise. Regarding wet spray, it seemed to me from viewing finished installations to be just as good as spray foam, for what it is worth. --Alphastream (talk) 04:19, 17 March 2008 (UTC)

Well done.Ccrrccrr (talk) 12:07, 17 March 2008 (UTC)

[edit] Heat transfer and climactic conditions

I just removed this section from the R-value (insulation) article because 1) it is better suited to this article, and 2) it has some errors.

In cold conditions, the main aim is to reduce heat flow out of the building. A large portion of heat losses are due to convection (particularly with poor weatherstripping) and conduction of heat from the internal air. A smaller but still important fraction comes from radiation from the human body (see thermal comfort) and interior furnishings. Windows are by far the greatest source of heat loss for all modes of transfer followed by the roof and walls. It is critical to reduce conductive/convective losses by good weatherisation, proper door and window seals, bulk insulators and miminising the amount of non-insulative (particularly non-solar facing) glazing.
There are buildings in which windows have the greatest loss; in other buildings they don't. That can't be stated as an absolute.
In the super-insulated passivhaus example with highly insulated windows: http://en.wikipedia.org/wiki/Passivhaus , thermal imaging demonstrated highest energy losses still occurred via the windows. —Preceding unsigned comment added by 219.90.145.245 (talk) 08:44, 17 December 2007 (UTC)


In hot conditions, the overwhelmingly greatest source of heat energy comes from solar radiation. This can enter buildings directly through windows or heating objects in its path which then re-radiate the heat downwards. Interior furnishings are thereby heated and become both conductive and radiant heat sources.
That is all true.
To reduce this heat gain requires adequate shading from direct solar gain, light coloured roofing, use of low-emissivity glazing and radiant barriers to interrupt the re-radiation of thermal energy that emanates from the outer structure of the building. It is important that radiant barriers face an air-gap to reduce conductive transfer from the material itself.
But this is phrased as if a radiant barrier is the only way to reduce that heat gain. That's not the case. The absorption/re-radiation mechanism involves conduction as an intermediate step.
Spray foam insulation has been proposed as having the properties of a radiant barrier but it has not shown to outperform traditional systems.[1]
That's a good article. Thanks for linking it. It does not propose that spray foam has the properties of a radiant barrier. Rather, it proposes that spray foam is a good insulator and air sealer. And the test results show that it works better than a conventional system--cellulose on the attic floor. Note that nothing tested in that article is a radiant barrier in the sense of having low emissivity in the far IR range. Rather the concept tested is the cool roof concept.
The article makes the point that the intensity of solar radiation is far higher than that usually generated by most household heat sources. Sol-air temps can reach up to 140 F in summer. Radiant barriers (a white roof) can reflect much of this energy away even before it reaches a conductive insulator. However, if you place foam directly directly in contact under a dark roof much of that solar radiation is not reflected but will conduct inward and result in high surface temperature at the foam. Even at good R values the underside surface temperature of the foam can be still quite significant - and the energy re-radiated downward on to the ceiling. However, the article does not consider the effect of a white roof to reflect most the energy away and then spray foam below the much cooler roof to deal with the rest of the heat energy. —Preceding unsigned comment added by 203.26.122.8 (talk) 07:29, 17 December 2007 (UTC)
A combination of materials may be required to achieve both properties of low thermal conductance and low thermal emissivity.
Certainly true, but one can reduce heat flow into a house from solar radiation with low thermal conductance without a radiant barrier. A radiant barrier, or a white roof, is sometime a great thing to include in such a system, because it requires less material. But the purpose of using the radiant barrier inside an attic is to get the same benefit for cheaper, not to stop a separate channel of heat flow that isn't stopped by conventional insulation. Suggested reading: ORNL radiant barrier fact sheet and Guide to Estimating Building Heating and Cooling Energy with a cool roof.Ccrrccrr (talk) 12:43, 15 December 2007 (UTC)
Our statements do not conflict - combination of material is better than relying on one type. Solar radiation energy is more effectively reduced first with a radiant barrier before it is allowed to move through a material of low thermal conductance. This will significantly reduce surface temperatures and the considerable energy load. —Preceding unsigned comment added by 219.90.145.245 (talk) 08:55, 17 December 2007 (UTC)
Radiant barriers and cool roofs are different concepts. Solar radiation energy is most effectively reduced first with a reflective roof. But once you've gone through the roof, it doesn't matter whether it was solar radiation or any other source of heat to the roof. The heat flow can be reduced by any combination of insulation and radiant barriers. Radiant barriers are a good choice, because the heat flow is downward, but the energy is no longer solar radiation, so there's not special need to block it with a radiant barrier, and there's no reason to believe that a combination of types of insulation is better than more of one type--they are in series not in parallel.Ccrrccrr (talk) 14:36, 23 December 2007 (UTC)
Foil and white roofs work on the same principle - reflect radiation/not re-emit it downward. I agree that having both may not be necessary. I am not sure if it has been modelled properly i.e. foil + batt, foil + foil, cool roof + batt etc etc. From where we come from, foil is usually anywhere between 25-50% the cost of batts/foam so it is for amount of radiant energy stopped per $spend is quite good. I am not sure how thick you need a bulk insulator be to stop that level of solar energy. There are not many light-coloured domestic roofs from where I come from due to aesthetic preferences. They are mostly used in commercial buildings with flat roofs. Foil is the first product of choice in roof +/- added bulk insulation.Dymonite (talk) 01:44, 24 December 2007 (UTC)

[edit] Organization and radiant barriers

The organization of this article is kind of a mess. I tried to improve it by collecting the introductory discussion of types (bulk vs. radiant) into one section and then having discussion of particular types later on. But the organization of the radiant barrier discussion is still poor--I think more of the information should be in the dedicated section later, and the first section should only address issues related to choosing between radiant barriers and regular insulation (or combinations).

The other sections are organized poorly too. There's a section on rigid panels, and then a subsequent section on one particular type of rigid panel. I think it would help to pick a scheme and stick with it, with more sub-sections.

I can see two schemes: One has, for bulk insulation, main categories of loose-fill, batts, rigid panels (with structural panels as a sub-section), spray-on. Another has main categories fiber insulation (e.g. fiberglass), foam insulation, cellulose, etc. That would fit the title of the article better.

I could even see having a main section on materials (foam, fiberglass, cellulose, etc.), and then another main section on form (batts, boards, etc.)

I'm interested in others' opinions. Ccrrccrr (talk) 14:05, 15 December 2007 (UTC)

Agreed on the bad organization, and your improvements are welcome. I will think on it more, but I like what you did up front. --Alphastream (talk) 03:17, 17 March 2008 (UTC)

[edit] Order of the insulation materials

Further thoughts on organization. The reasoning behind the current order of materials isn't clear. I think we should either go for alphabetical or by type (batts, loose-fill, etc.). Thoughts? --Alphastream (talk) 20:28, 18 April 2008 (UTC)