This page includes research reports from the year long study covering cob wall performance in moisture control, temperature moderation, dew points, specific heat capacity, R Value, full energy analysis of solar thermal performance, energy profile, energy comparisons between Eco-Sense and a conventional BC residence, solar PV analysis, building code discussion,water usage, policy and barriers… nerdy stuff! In partnership with Cascadia Green Building Council, and generously sponsored by Van City and The Real Estate Foundation
Cascadia Report: Affordable, Sustainable Homes: Eco-Sense and the Future of Green Building affordable-sustainable-homes. (PDF)
The Living Building Challenge
Pingback: Energized, over carbonated and gassy? | Ecosenseliving's Blog
Pingback: Affordable, Sustainable Homes: Eco-Sense and the Future of Green Building | Ecosenseliving's Blog
Pingback: Eco-Sense Oct 2011 Email Update | Ecosenseliving's Blog
Pingback: Emerging Green Builder’s (Eco-Sense Presentation) | Ecosenseliving's Blog
Question: what firm installed your grid-connected PV system? I have a place near Parksville, and I need an installer who is familiar with the process, particularly in dealing with BC Hydro. Preferably someone in the local area.
Thanks,
Derrick
Mike Isbrucker (Alternative Electric) – Electrician – Sustainable Energy supplier – grid tie
250-85-SOLAR (250-857-6527) mike@altelectric.com
Mike lives near Cowichan Lake here on Vancouver Island.
Ann
Curious how you got approval for your composting toilet. Looking to do a retrofit on a cottage with no septic and it looks like the BC Building Code is pretty draconian…
Next year we want to realize air solar heating in the cob house. What is yours opinion: pros and cons
Yuriy
Hi Yuriy, There are many factors that would limit the effectiveness of air solar heating in a cob house, unless the cob house has an insulate cape to boost insulate value, or unless the climate is such that heating demands are limited. With Air solar heating, the amount of energy air holds or the specific heat capacity of air, limits its ability to conduct large quantities to the slab under the home. Though I wouldn’t rule it out as an additional source… what we have really learned for an all cob home, is that the north sides of the home, and areas that do not get sunshine should be insulated in some manner, (wood chip clay infill, light straw clay, blown cellulose…), and then depending on the solar insolation and the heating degree days, you could feasibly work out a solar battery under the home but using solar thermal hot water collectors and water as the transfer mechanism rather than the air. I had started to write a program to calculate such… but well gardens and spring came along. I do like the idea of the Annualized Geo Solar battery concept that originated from solar air systems… but for the climate we live in in Canada… it does not quite do the job and hence water seems to be catching on.
Cheers,
Gord B
Question:
These results of cob under a vapor barrier system are very interesting, do you think a passive house (passivhaus) could be built using cob as its substructure? Would you think that the risk of interstitial condensation would be the only barrier in achieving this goal?
Thank You,
Oisin
Hi Oisin, actually we did not use any vapour barrier in our cob walls. To achieve passive house standards one could use load bearing cob along with appropriate site, orientation, and other passive solar design features. It would be essential to install a thermal wrap the load bearing cob with a thermal layer on the North, east, and west exposures. On our home, we have installed this wrap so far on the north wall. We studded it out with 2×4′s to create a 8-12″ cavity…put burlap over the studs…then stucco wire…then used blown in cellulose to fill the cavity. Then it was plastered with a very thick high straw plaster, then a finish plaster (lime or earth…as this wall is very protected). We are just getting ready to do a similar process on the east wall but will use a PE house wrap that breathes instead of the burlap as this wall is exposed to driving rain and wind. Important to note that the home achieved a functional r-22 as measured by energy inputs before any additional insulation. We think that a properly designed and insulated load bearing cob structure could theoretically achieve passive house standards…certainly easy to achieve air leakage standards…our home is extremely tight.
Ann
Hi Ann, thanks for you reply. Does this method not prevent the cob from having direct solar gains because of the external wrap? How can the moisture in the wall evaporate to the external surface if there is not a significant difference in temperature?
Oisin
It reduces the solar battery effect…especially if it was done on the south wall…which we would never do. However, it wouldn’t reduce the solar battery effect (which is the ability of the outer surface of the wall to heat up and retain the heat over a period of time), by too much for the sun that does hit the eastern/western walls. With at least 2 inches of earth plaster there is still a significant heat storage capacity which would certainly impact the deltaT (temp differential) in the mass wall assembly.
The moisture does not need a significant deltaT due to the clay in order to move through the mass wall. Clay has a surface charge and attracts the water (a polar molecule) and has the ability to wick and equalize moisture in the wall without temp as a mechanism.