Plastering Straw Bale Houses in Cold Climates –

Written by Andrew Morrison

Snowed Inn straw bale house
The Snowed Inn straw bale house

Plastering straw bale houses in cold climates is a difficult process and site conditions have a big impact on the results. Most people are aware that plastering in direct sun is not a great idea, especially with natural plasters. What many don’t realize is that plastering in cold conditions and/or wind can be equally as damaging to the plaster.

It may seem obvious that it is not good practice to plaster when the temperatures are below freezing. This is because the water in the plaster can freeze as soon as the mud is placed on the wall. What if the temperature is around 40 degrees F? If you are using Natural Hydraulic Lime (NHL 3.5) you cannot apply the material below 40 degrees F or above 85 degrees F.

Furthermore, you must protect the plaster from direct sun, high wind, frost and rain for 72 hours. This can be difficult if you live in a cold climate where the temperature drops in the evenings and over night. Wrapping the building in tarps will help keep in some of the heat gathered during the day and produced through the curing process; however, you may be required to add heaters to the building to fully protect the plaster.

Other plasters are able to handle direct sun, wind, a little frost, and other adverse conditions; however, those plasters are usually modern synthetic plasters. Natural plasters, because of the fact that they are natural and do not have chemical additives to deal with adverse conditions, are not likely to be able to handle such climatic conditions. For this reason, natural plastering must be completed under moderate conditions or must be at least protected from extremes as noted above.

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12 Responses

  1. I do not have any current plans to do a workshop in that area. I have started doing workshops on my property because I have had some problems with past hosts dropping out at the last minute. I have several workshops scheduled for this summer including May 5-11, June 16-22, August 4-10, September 1-7 in New York State, and September 15-21. Check out for more on the workshops.

  2. Thank you for the free 7 essential steps for building with strawbales Andrew.
    I live in Victoria, Australia and I can say is, I am so looking forward to the adventure of building a strawbale home! Just wish you did workshops here :O)…Cheers!!

  3. Hi Teresa. I am considering making a trip down under for a workshop this year. Weather and a site are a factor. I have a man who is interested in hosting, so we will see where it goes. Feel free to kick some tires down there and see if there is a desire to have a workshop amongst your friends. Thanks and maybe see you soon!

  4. Andrew!Thanks for every single image or word in the free 7 essential steps for building with strawbales. You have to know that it is very difficult to introduce strawbaling in Greece. Local/Regional brainwashing towards the Profit Way Model(Non-eco)of Looking at Buildings has to be reversed in order to introduce the Green Way of Building. Maybe you should think how you might be able to mix summer vacation on the Greek Islands in the Aegean with lecturing and/or workshop/seminars to help us reconsider the way of building.

  5. Dimitrios,
    I would love to come to Greece if the cards line up. I hope that you find success in the meantime and thanks for your feedback.

  6. Hey Andrew, thanks for all the great info, would you recommend a NHL5 in northern climates? or would you stick to 3.5. I have your video and after speaking with the supplier they recommended a 5 due to the variation in local climate -40 to 30 celcius!

  7. Hi Andrew. Do you have on your site information about daily temperature and humidity (measured for long time, e.g. 1 year) from your area?

  8. Hi! How does one avoid frost damage in an already existing straw bale home? Or rather, what do one do to avoid it, if one is planning to build one? There is a very high humidity factor where I live, and the temperature fall will cause expansion in the water trapped in the pores of the plaster, causing it to break off. Is there any way to avoid this, and still keep things earth friendly?

  9. Angie,
    Humidity is the hardest thing to manage in a bale home. There really is no way to keep it out of the plaster or bales as it pervades everything porous. I would reconsider building with bales if the area has high relative humidity much of the year. You could install a dehumidifier to help with interior humidity but this will not help with the plaster concern you have.

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