Sharing information and promoting earthbag building
|aHow to Make Vents in Earthbag Buildings
Questions answered by Kelly Hart
Q: The climate in Malaysia is hot and humid as we are only a few degrees from the equator. I do wonder about the suitability of the dome shape - especially the roof in this climate. How do we ensure enough ventilation?
A: I provided ventilation in the earthbag domes that I have built by arranging inlet air vents near ground level, and outlet vents at the very top of the dome. This worked very well, and is easy to do with large diameter pipe (I used inflated tether balls as vent closures). You could feel the air rush by with the convection current!
Q: With the air vents in your papercrete dome, do you close them in the winter and open them in the summer?
A: In general this is true, it depends on the season whether you want the fresh air or not.
Q: Should vent block or concrete or brick infill panels within earthbag be added after the earthbags have been fully built and tamped, and had the roof weight added to it? I'm wondering about differential settling.
A: I would say that this depends on the fill material and how well tamped it is. Also, in some circumstances it may be difficult to inserts these elements later. I would think that as long as the fill material is fairly dense and well-compacted, it would be safe to do this as the project is being built, which would likely be easier than later.
Q: I was thinking that tile chimney flue squares would be nice to use for vent openings, but might get cracked when tamping layers above? I know adding sections of round pipe for little vents like people do would be really strong--don't know how cheap it is overseas.
A: It likely depends on how thick and/or how brittle the flue sections are; some experimentation is in order here. Short sections of plastic pipe are often available as remnants or salvage.
Q: Do you think a turbine roof vent would be sufficient to circulate air and dry the place out? It’s a 200 sq ft dome structure.
A: With a dome that small a turbine vent at the apex of the dome should perform well, as long as there is sufficient inlet air somewhere lower in the dome. Having a way to stop the airflow when you want is needed, and I have used an inflatable tether ball for this.
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