Hi Michaell when a Canadian says cool, do they mean -20 and snow drifts ? :)Im not a scientist either but I would have thought that for a convection current to operate you would need a fair sized air space for the circulation to take effect. Double glazed windows can go up to 22 mm cavity gap before convection begins to become a problem. I could see there might be a problem if you had a bale wall with an external cladding of wood to protect it and there exists a big gap between the wood cladding and bale wall (aswell as a big fire risk from a chimney effect) Porous iinsulators like straw bales could easily have their insulative value eroded if there is a convective current running over its surface like this. Is it not conventional thinking that putting ANY barriers inside a bale wall will create more problems unless done very carefully. Just so thoughts from France.
A queation to Canadian SB builders or any one buildig in similar climates. I bought Chris Macwoods details book in which all the designs pay particular attention to having a vapour checkinstalled. This might be a stupid question but is not possible to build a straw bale wall that doesnt need the vapour check? does anyone know of SB buildings in Canada being built without a vapour check? where will the condensation be, on the interstitial gap behind the external render?
regards Paul
From: "Michael lough" <michaelklough@sympatico...>Reply-To: mkl18@pobox..., European strawbale building discussions<strawbale@amper....muni.cz>To: strawbale@amper....muni.cz Subject: [Strawbale] convection and humidity in straw bale walls Date: Fri, 06 Jan 2006 20:06:50 +0000 Hello there from cool but getting warmer Canada?A little while ago I read some information on the subject of convection within straw bale walls and would like to know if this is a resolved issue in Northern Europe ?Hasit been established with support from testing or evidence of problems that this phenomena exists in the straw bale world ? I am not a scientist so I cannot reach a conclusion from scientific data myself but I could understand simple terms?8)I hope this will be possible as there is much debate here on the subject and there has been no testing here as far as I know. The idea that bale walls arein fact likely to rot without there being barriers in between each course is worrying some people!Thank you all for your consideration Michael Lough ____________________________________________________ European strawbale building discussion list Send all messages to: Strawbale@amper....muni.cz Archives, subscription options, etc: http://amper.ped.muni.cz/mailman/listinfo/strawbale ____________________________________________________