[GSBN] Question about SB insulation at foundation/ceiling

[Chris Magwood]

Hey Bruce,

What about "shredded plastic bags" in the form of used/discarded carpet? 
There's a bunch of that long-lasting petroleum that's already been 
processed, used and is about to insulate landfills around the world. I 
know there are questions about the insulative value, but there has to be 
some, and its a matter of figuring out how many layers are needed in a 
particular building. I usually sandwich my used carpet with a poly 
barrier above and below, figuring that moisture is the chief enemy of 
r-value in this material. It's worked to keep the Madoc Arts Centre 
building meeting its net zero energy targets since 2008, and we 
calculated it as r-10 for five layers.

Wouldn't it be great if someone were to undertake some testing on this?...

Chris

On 12-01-24 11:32 AM, Bruce King wrote:
>
> The idea of using any cellulosic material at or near grade just makes 
> me nervous and ill.  We have a world of experience telling us that 
> wood, paper-faced gypsum board and straw don't last long there, or 
> anywhere near there.  Recall Kim Thompson's well-documented problems 
> using bales between floor joists over a Nova Scotia crawlspace.
>
> But how, then, to insulate?  I guess I would argue for the use of a 
> naturally-occuring substance that can make a durable and also 
> effective insulator in the presence of moisture, namely petroleum.  It 
> takes a bit of unpleasant processing to turn oil into foam (that is, 
> something that entraps air which is the real insulator), and god knows 
> we need to improve on the weird stuff currently on the market.  But if 
> there is any good use for petroleum, this is surely one.  Not for our 
> cars, not for crappy plastic packaging & throwaway junk, but for 
> effective, durable, reuseable insulation.
>
> Or anyway I'm still waiting for a viable "natural" ground insulation 
> suggestion that isn't a super labor intensive fuss job.
>
> Shredded plastic bags, anyone?
>
> Thanks,
>
> Bruce "Oil gladly pay you Tuesday for some polyisocyanurate today!" King
>
>
>
> On Jan 24, 2012, at 8:08 AM, Frank Tettemer wrote:
>
>> Hi all,
>>
>> I have just received a message from the designer of the yoga centre, 
>> that I was busy criticizing in my previous post.
>> The Sivananda Yoga Centre is still alive and well over a decade later.
>>
>> I apologize to the GSBN group, and to Michel Bergeron, for handing 
>> down that mis-information about the Sivananda Yoga Centre. Michel has 
>> had no such reports of mold problems, and as the designer, he would 
>> certainly be the first to hear about it.  It takes a foolish commnet 
>> from someone like me, to deeply upset the credibility of straw bale 
>> construction. And worst of all, this negative comment coming from a 
>> straw bale builder!
>>
>> There's a strong lesson in all this for me, to examine all my sources 
>> of information, and to not speak about things of which I have no 
>> first hand knowledge.
>>
>> Deeply chagrined, deeply humbled,
>>
>> Frank Tettemer
>>
>>
>> On Jan 24, 2012, Derek Roff wrote:
>> I'm not sure if this discussion is still alive on the linked site 
>> that Joyce posted.  The newest posting is just about a year old, but 
>> perhaps the discussion will warm up again.  Bruce King posted a 
>> comment last year, when the discussion was current.
>>
>> Something that wasn't mentioned in the article or comments is the 
>> naive assumptions regarding the effective insulation value of the 
>> strawbale waffle slab design, even before the bales start to rot. 
>>  The assertion is made, and not challenged, that the under-slab 
>> strawbale insulation would provide R-50.  Whatever number we accept 
>> as the insulative value of each bale, the thermal bridging of the 
>> concrete in the matrix would cut the effective insulation of the 
>> waffle slab design dramatically.  Thermal bridging isn't a problem 
>> with the design sketch that Joyce included, but the risk of rot 
>> probably remains.
>>
>> There is an alternative approach that uses bales as floor insulation, 
>> but above grade.  After a European Straw Building gathering a few 
>> years ago, traveling with Catherine Wanek, I visited SB buildings in 
>> half a dozen countries, including several that used strawbales in the 
>> floors, to meet Passiv Haus design goals.  All of these structures 
>> were build on piers, so that the bales were above grade and isolated 
>> from the moisture concerns that afflict buried bales.  Here is a link 
>> to one example, the S-Haus in Austria.
>>
>> http://www.s-house.at/presentations.htm
>>
>> Bale-on,
>> Derelict
>>
>> Derek Roff
>> derek at unm.edu <mailto:derek at unm.edu>
>>
>> On Jan 23, 2012, at 10:40 AM, Frank Tettemer wrote:
>>
>> Well now,
>> that is pretty interesting.
>> Thanks, Joyce, for sounding the alarm.
>>
>> Before I actually (physically and personally), had built any SB 
>> houses, I naturally ass-u-me-d that bales in the floor and ceiling 
>> were a good idea.
>> It is too bad that the article in finehomebuilding references the 
>> experimental work of Michel Bergeron, of ArchiBio, in the 
>> ground-breaking book of Steen/Steen/Bainbridge/and Eisenberg.  I love 
>> the book, and it is what gave me hope for the idea of burying bales 
>> below grade.
>>
>> Fortunately for me, Linda Chapman, (archi. from Ottawa), talked with 
>> me about doing this in the early nineties.
>> She had boldly gone where no one had gone before. And the floor rotted.
>>
>> And there was the evidence from the huge three-story yoga retreat 
>> centre, built in Quebec,
>> which was such a rotten embarrassment, that I won't mention it anymore.
>>
>> Then there's the theory that if you stick each bale into a garbage 
>> bad before you bury them under the floor ...
>> just to say I did, I took a bale, put it into a garbage bag, and 
>> placed it into a weather-protected shed, to see what happened.
>> First of all, it took three trys with the garbage bad to place a bale 
>> into it, without it being punctured by straw.
>> Secondly, during the summer of 2000, which was a fairly wet year, the 
>> bale self-composted, with out having had a drop of rain on it. I 
>> imagine that relative humidity was all it took. It was full of mildew 
>> in two months time.
>>
>> I have to say, though, that the idea is so intriguing, that it 
>> captures the imagination of quite a few clients, who would wish me to 
>> design a foundation using straw bales.
>> Maybe it's just a stupid idea, here in a climate with huge weather 
>> extremes, (+35C to -35C), and many days of damp rainy weather?
>> Maybe all the ideas have not been tried as yet?
>>
>> Frank
>>
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www.chrismagwood.ca
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