[GSBN] Fwd: Decrement factor of SB walls

Tue Dec 6 16:21:49 UTC 2011

Yes, Dereck, you're right. In this example there is no exterior
plaster/render. Instead, there is a 16mm rainscreen panel (could be
fiberwood).
I attach here a picture of the example presented in the book.

Thanks

Jorge VK

On Tue, Dec 6, 2011 at 2:34 PM, Derek Roff <derek at unm.edu> wrote:

> Thank you, Jorge, for greater details on the French research.  It appears
> to me that the construction describes a wall with earthen plaster/render on
> the inside, and no plaster/render on the outside.  Is this correct?  If so,
> the lack of an exterior plaster/render layer would have a significant
> effect on the thermal characteristics, I would think.  As well as fire
> resistance, structural rigidity, moisture buffering, and perhaps a bit of
> insect and rodent deterrence.  I know that some people build this way, but
> it seems imprudent to me.  Have I misunderstood the nature of the wall that
> Jean-Pierre Oliva and Samuel Courgey are describing/testing?
>
> Thank you,
> Derelict
> Derek Roff
> derek at unm.edu
>
> On Dec 6, 2011, at 5:52 AM, Van Krieken wrote:
> John,
>
> As I wrote before, the best source of information (I have) about this
> issue it is the book writen by Jean-Pierre Oliva and Samuel Courgey (
> L'Isolation Thermique Ecologique).
>
> Jean-Pierre Oliva is perhaps the best known french bio climatic architect,
> and since many years a great enthusiast of straw bale building. His books
> (also La Architecture Bioclimatique) can be found at Amazon.
>
> Unfortunately, this book is only in FRENCH. I am sorry if my translation
> was not well done, so I include here the original text in french.
>
> Citing their book, page 175, concerning a wall with wood structure and
> straw bales with medium density (80 to 110 Kg/m3, strawbale section
> 34x46cm. Vented façade (or rainscreen claddind) in exterior, and interior
> with clay render.
>
> Note.: I attach to this discussion a paper wrote by Jim Carfrae, attached
>  to this forum last January, 22, where you may have more information about
> the benefits on using of a rainscreen clading in a straw bale building,
> specially on humid climates.
>
> The  rainscreen cladding is  included in the calculation of JeanPierre
> Oliva for this next example:
>
> Wall:
>
> 1. Bardage bois (2cm)
> 2. lattes support et contre-latte (6cm minimum)
> 3. Panneaux pare-plui contreventans (16mm)
> 4. Poteaux bois massif (4x20 tous les 60cm)
> 5. Liteau de maintien des bottes (toutes les 2 bottes)
> 6. Botte de paille posé sur champ (36cm)
> 7. enduit terre (30mm)
>
> Caracteristiques Thermiques et environnementales:
>
> Coeficient de déperdition thermique U (W/m2K) / R (m2K/W)
> .................................. 0,13 / 7,76
> Pertes dues aux points thermiques
> intégrés....................................................................
> 4%
> Capacité thermique intérieure quotidiennekWh/m2K)..................................................
> 15 (forte)
> Capacité thermique intérieure séquentielle ....................................................................25
> (moyenne)
> Déphasage (heure) / Atténuation du flux de chaleur
> (%)..............................................16h / 13%
> Epaisseur supplementaire pour atteindre le niveau
> "passif"....................................... 0
> Bilan "CO2" du m2 de
> paroi.............................................................................................
> -83 kg CO2 eq
> Bilan "energie grise" du m2 de
> paroi..............................................................................
> 62 kWh
>
>
>  Translation (?):
>
> 1. Thermal loss U (W/m2K) / R (m2K/W) ..................................
> 0,13 / 7,76
> 2. Losses due to thermal
> bridges............................................... 4%
> 3. Daily indoor heat capacity (kWh/m2K)................................
> 15 (strong)
> 4. Sequential indoor heat capacity (kWh/m2K).......................25
> (medium)
> 5. Phase shift (hour) / mitigation of the heat flux (%)...............
> 16h / 13%
>
>
>
> All the best
>
> Jorge VK
>
>
>
> ---------- Forwarded message ----------
> From: John Swearingen <jswearingen at skillful-means.com>
> Date: Tue, Nov 29, 2011 at 1:35 AM
> Subject: Re: [GSBN] Decrement factor of SB walls
> To: Global Straw Building Network <GSBN at sustainablesources.com>
>
>
> This is very interesting, and fortunately in English.  Unfortunately, I
> don't really know what it means.  Can you explain more?
>
>
>    - U-value I know.
>    - Thermal bridges to nowhere, I know, but what is a "vented facade"
>    (above).
>    - What are daily indoor heat capacities and sequential head
>    capacities, and what does "strong" and "medium" mean?
>    - Phase shift mitigation?
>
> Thanks!
>
> On Mon, Nov 28, 2011 at 3:40 PM, Van Krieken <vankrieken at gmail.com> wrote:
>
>> Hi
>>
>> The best source of information about this issue (and many others
>> concerning insulation, thermal mass, etc) it is the book writen by
>> Jean-Pierre Oliva and Samuel Courgey ( L'Isolation Thermique Ecologique).
>>
>> Citing their book, page 175, concerning a wall with wood structure and
>> straw bales with medium density (80 to 110 Kg/m3, strawbale section
>> 34x46cm. Vented façade in exterior, and interior with clay render.
>>
>>
>> Thermal loss U (W/m2K) / R (m2K/W) ..................................
>> 0,13 / 7,76
>> Losses due to thermal
>> bridges............................................... 4%
>> Daily indoor heat capacity (kWh/m2K)................................ 15
>> (strong)
>> Sequential indoor heat capacity (kWh/m2K).......................25
>> (medium)
>> Phase shift (hour) / mitigation of the heat flux (%)............... 16h
>> / 13%
>>
>> Unfortunately, this book is only in English. Jean-Pierre Oliva, is one of
>> the best known french bio climatic architects, and since many years a great
>> enthusiast of straw bale building. His books (also La Architectire
>> Bioclimatique) can be found at Amazon.
>>
>>
>> All the best
>>
>> Jorge VK
>> Portugal
>>
>
>
>
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>
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