[GSBN] Can bale buildings be air tight?- How to ventilate

[Derek Stearns Roff]

I'm in partial agreement with Graeme, and I appreciate his comments.  I'm opposed to waking up dead from any cause, although I admit that this reflects prejudice and supposition in my case, since I have never tried it.  But I think we need to be careful of false dichotomies, spurious connections, and wishful thinking.

I advocate healthy buildings and a healthy world, and I suspect everyone on this list would say the same.  I advocate connection with the natural world, while preferring to sleep in a healthy natural house, rather than spending my life in the much more natural state of our ancestors 100,000 years ago.  I don't have the skills needed to survive as humans did deep in prehistory, nor do I have the community and habitat to support that lifestyle.  Like most of us, I am striving to understand the best balances and combinations between old and new.

I think it is a false dichotomy if we equate tight houses with health risks and leaky houses with health.  How many cases can we document, of people who have woken up dead because the mechanical ventilation system in their tight house failed overnight?  Around here, the people who are killed by their houses each winter live in leaky houses, with bad wood stoves or fossil fuel furnaces.  Most of the people with chronic home-induced health problems don't live in well-designed tight houses, rather they live in average to leaky homes, with compromised heating and coolings systems, mold, toxic materials, and ventilation problems.  Having random leaks does not guarantee good ventilation, nor good indoor air quality.  Neither does having a mechanical ventilation system.  Creating a healthy house requires knowledge, understanding, and attention to many details.

Derek

Derek Roff
derek at unm.edu<mailto:derek at unm.edu>

On Mar 14, 2013, at 3:51 PM, Graeme North <graeme at ecodesign.co.nz<mailto:graeme at ecodesign.co.nz>> wrote:

Well my 2c worth is that in NZ we have a long history of cold damp houses, in a very humid mostly temperate climate.  (As it is at the moment we are in the grip of the worst drought for over 70 years so any hint of damp would be welcome.)

That aside - the best strategy I have found for drying out damp houses is to use hygroscopic materials in the fabric of the house - and the best and easiest is earthen walls or at least earthen plasters on any suitable substrate such as dry wall.  Of course to help get over cold we insulate and that's where sheep's wool, or strawbale,  or low density earthen materials, come into their own.  Condensation on windows and the accompanying wet window sill syndrome simply vanishes.  Needless to say we don't have several cm of snow lying around but we do get some pretty good frosts.  Then reducing the size of houses and the size of windows in them also helps. Lets face it, oversized badly orientated triple or quadruple glazed self ventilating thermally broken windows are still not nearly as good as a bit of well insulated wall at keeping heat in or out.

I suggest that the approach of using more and more of the earth's resources to sort out these building issues  may not be a good primary design strategy, especially when it leads to oversize buildings, with oversized windows needing mechanical ventilation systems etc., -  mechanical systems that are only as good as their energy supply.  I don't want to wake up dead of asphyxiation in an air tight building because the electricity failed while I slept.

This is not to dismiss some very good building science and its associated research, but I am finding this conversation on interior air quality in air tight buildings a bit disturbing when we end up with buildings so tightly sealed that the occupants are at risk from either the building fabric itself, or even more alarming, from their own breathing!   People would be much healthier outside the building under these circumstances.  Interesting, isn't it, how, if a person feels ill we often take them outside, where they usually feel much better?  We really do need protection from the built environment.

I prefer a design approach that minimises the use of expensive, resource gobbling, and complicated materials and systems.  A colleague of mine sums it up thus:
The.... division is between those who fling open their doors to embrace the day, and those who huddle behind triple glazing worrying whether they are going to be comfortable.   Tony Watkins FNZIA



Graeme "Stirrer"

Graeme North Architects
49 Matthew Road
RD1
Warkworth 0981

www.ecodesign.co.nz<http://www.ecodesign.co.nz/>


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