Strawbale? Good or bad???

[nightfury]

I am sure this has been discussed on the forum before, but is strawbale a good option to use for infill?

[Satamax]

Well, i'm looking into this for myself.   I wouldn't say infill. The straw needs to breathe. They seem to say that you can put osb, plasterboard etc, with a vapor barier on the inside. You need a vapor barier there. But on the outside, you have to have a vapor permeable film. or protection.

Usual finishes are lime based renders. Earth based like cob, a mix of the two, or wood panneling with a  film which lets the vapor out. And the last layer on the ground is often  done with air entrained entrained concrete blocks (Ytong over here) for moisture seepage protection and mice protection. As well, they often use a sort of metallic mesh on the bottom of wood panneling, so mices don't go living in it.  Few information at permies.com for example. And if you can read french, i can show you a few sites where  there's a good wealth of informations. The straw bale on it's edge insulates better than laid flat. And in this case is good for "passive" house. Tho, it's not quite good enough for roofing. But but in a roof, 16" of wood wool will do for passive.

Hth.

Max.

[irishcountry]

Seems like a no brainer when it comes to insulation and energy efficiency .  Not sure how helpful this is but here is a article from a nearby area in Michigan .  I'm sure there's more on this guy on the internet as well .  We can have some wet times of year here so wonder if their are any cement based products for the exterior  that "breathe" like shotcrete ect.  Heres the link --http://www.mlive.com/living/jackson/index.ssf/2011/01/post_5.html

[Hilltop366]

Can't find the original article I was reading a while back but I think it was related to this http://www.cmhc-schl.gc.ca/publications/en/rh-pr/tech/00-103-E.htm look around the CMHC web site for more.  Where you are located and building design & materials seem to be the main factors of success or fail.

[SPIKER]

I believe it was Mother Earth News mag that had some good information on them back err maybe 10yrs ago.   Other than that I can't help much over Google...

Mark

[mesquite buckeye]

Great insulation, but I worry about termites. They love straw. ;D

[shinnlinger]

I was involved with two in Oregon and was going to insulate my current house with bales but got a real good deal on poly iso out of a lumber kiln so went that route instead.  There are a lot in the southwest and a lot in quebec with a fair amount everywhere else.  You would be surprised

THe key question I have for you is where are you getting your bales?  If you have to have them custom baled and trucked in from 2000 miles away it may offset any good juju you hoped to capture.  It will also cost you a pretty penny as diesel is key for everything I just typed.

Dave

[shinnlinger]

You encase the bales in a natural plaster where it is pretty impervious to any bugs or anything like that. 

Dave

[scsmith42]

I looked into using strawbale insulation in my new shop, and it was actually more expensive than other options. 

[shinnlinger]

If you live in an area like Oregon, which banned big burns of fields and farmers have to bale the straw just to get rid of it, it can make sense, but if you have to have it trucked in it probably doesn't.  Another factor is labor.  Smearing plaster is unskilled.  If your building it yourself, and have a bunch of friends, it can be fairly cheap to have a smearfest, but if your paying a contractor it will not be cost effective.  A contractor will probably want to blow concrete on it as well which is a bad idea because then the bales can't breathe.  There is a house near me where the woman had conventional walls built around the bales.  Other than being 20" thick, you wouldn't know it was straw bale, but it certainly wasn't the cheapest way to go.

[ziggy]

Straw bales need to breathe from both directions -- no vapor barrier (or non-breathable finish) should exist in any quantity on either face (inside or out). Natural materials, in general, should be capable of "breathing" to transpire moisture naturally throughout the year.

I have written a fair bit about building a timber frame / straw bale house on my website, linked in my profile. Straw bales, like others have mentioned, make sense depending on availability, ability to do the labor yourself or with inexpensive help, etc. There are enough tricks to know about bales to warrant taking a class before attempting anything yourself, and you can end up saving time/$ down the road.

All that said, I think straw bales are a lovely option, and timber frames and straw bales actually make a great combo.