Exterior Insulation for Adobe Masonry Walls
Does anybody have experience with exterior insulation of adobe masonry walls? I know that materials such as spray foams are used. But I’m considering the possibility of applying 2-4″ of mineral wool insulation board to the exterior, lathing over it with vertical 1x4s to create a rain screen effect and then applying a 3-coat stucco over that. I can’t see any downsides, except that I haven’t heard it done before. (I know it’s done over wood framed walls.)
What are people doing these days to increase the energy efficiency of adobe masonry walls in new construction? Do any of you fellow readers have any favorite websites on the subject of adobe masonry homes?
And yes, I Googled every combination of search terms I can think of. All I find is the same material I was reading in the 1980s and early 90s. It’s still good material, but doesn’t answer a lot of the questions we face these days.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Replies
Antonio,
I have been looking for the same information for a while, and you're right, much of what is available is old and largely anecdotal. Adobe isn't discussed much on GBA either. I found some resources you might find helpful:
1) Joe Lstiburek has written quite a lot about continuous insulation on masonry buildings. BSI-079, Deep-Dish Retrofits, shows some construction details for insulating over structural brick and CMU walls with both rigid foam and mineral wool.
2) Colorado Earth has a lot of data on their website in the Resources tab. They are a company in Golden, CO who manufacture and build with compressed earth blocks. There are white papers written by Emu Engineering and Energy Logic that discuss projects built recently in Colorado. The 'Performance of Earthen Structures' section has a lot of archived material from New Mexico on how to characterize adobe structures both with and without exterior insulation.
3) AdobeBuilder.com features a slide show, 'Adobe House by the Rio Grande'. This builder fastened a 2 inch layer of EPS foam board to the outside, followed by metal lath and stucco. I believe this a common upgrade in that region.
4) At the outer edge of DIY, there is a fellow in Silver City, NM who is building a traditional adobe home (website, visioncreationadobe). He is insulating the north wall with a framed straw-clay outer wall, covered with wire mesh and clay plaster. It's quite labor intensive, as the author admits.
I live in Colorado, not far from the recent Marshall fire. Fire-resistant construction is on everyone's mind these days. If you go ahead with your project, I'd be interested to hear how it goes.
Thank you so much for your detailed reply. This is a really great resource.
GBA is full of all kinds of good information but I do wish they would give a little more attention to approaches that rely a little more on natural materials, local resources, etc. It seems like the thrust is to turn every house into a petrochemical foam wrapped box.