Bob Alexander, who owns and operates LX&R Design based in Chamita, New Mexico is much happier these days.
After designing sustainable solar efficient homes for more than a decade he says he has found the perfect material for the owner-builder do-it-yourselfer.
"Pumice-crete casting is the best thing that ever happened to sustainable housing." he says. "This material is fire proof, rodent and insect proof, rot proof, non-toxic and relatively cheap and easy to use. It doesn't cost an arm and a leg to build a really nice home with it."
As for proof, Bob's friend, Ron Vanderzanden, recently built a pumice-crete casted home for his sister at a cost of around $50.00 a square foot. This includes the cost of the well, septic system and electric. And it was done using a low-tech method and untrained labor.
"For years I have been interested in the wall casting idea and I did a lot of research on it. Casting has several advantages over many other forms of construction, but, many of the casting materials I looked into had problems such as excessive shrinkage which led to cracking and low R-value which results in higher heat loss."
"Another big draw back is that these materials aren't well known to the Construction Industries Division who issue building permits here in New Mexico and they are reluctant to put their stamp of approval on something they don't know much about."
"Pumice-crete, on the other hand, has been in use here since at least the 1940's and, although it is still considered an 'alternative building material', getting a building permit for it is pretty straight forward."
"It's not rocket science to build a really nice home with it. Another big plus for me as a solar designer is the fact that it has high mass, meaning that it will store solar heat. And it doesn't use a lot of wood which is getting more expensive."
"With the rising cost of heating fuel, it only makes sense to use solar energy if you can, but, you don't build a good solar house by simply adding a lot of glass. That creates a greenhouse effect and the house will soon overheat. You need a fair amount of mass to soak up that heat. At night that mass will release its' heat back into the home keeping your heating bill down. The reverse is true in summer. If you cool the house down at night it will stay reasonably comfortable through most of the next day."
"It still takes a good solar design to achieve high solar efficiency, but the pumice-crete casting technique is something almost anyone can do and it doesn't cost much to get going with it."
"We used a paddle batcher ten years ago, but, it takes a bit more work."
which does a better job than an cement mixer, but, you could mix it by hand in a wheelbarrow. The forms were made out of ¾" plywood and a metal yoke system, which Ron designed, was used to hold them in place. The forms were reused as the walls grew taller. This is referred to as 'slip forming'. Even the interior walls were casted, but, full-height plywood forms were used there which required stronger bracing."
"An old electric forklift was fitted with a platform which would accommodate two wheel barrows making it easier to get the mix into the forms at the higher levels. It can be done using 5 gallon buckets. In fact, that is how Ron and his wife built their own house ten years ago, but, it takes a bit more work."
"You can stop whenever you want to and start back on it when you can. Doing a little work each day makes it easier on you and your budget. You can even use the stuff as roof insulation, but, it is heavy in the wet state, so strong roof bracing is recommended."
"It is also possible to make building blocks out of the stuff and stack them like adobes. If the building site is remote, you could make them in your back yard on weekday evenings and put them up on weekends once they are dry enough to handle."
"Pumice is a lightweight rock available locally for around $14.00 a cubic yard. The only other ingredients are water and Portland cement which is only 1/15th of the mix by volume. Making a good casting mix requires a little practice. You don't want to over mix the stuff since this will cut down your R-value."
"Rons' sisters' house has 16" exterior walls which were required to meet current energy codes. No additional wall insulation is required. This home features arched windows and doors and flared window and door openings resulting in a nice smooth appearance."
"Our goal isn't to build homes for people. It's to show people how they can build their own high-quality homes using inexpensive materials and relatively low-tech methods. We have started to write a booklet on this method and we may eventually produce a video tape on it."
"Traditionally, people have had to take out a long-term mortgage to get a high quality home. This cycle has gotten us to where we are now. I would like to see this change, so people can live within their means. It does take some 'sweat equity', but I know it is possible."
For more information on pumice-crete casting and sustainable solar home design, visit the LX&R Design website at www.lxrdesign.biz or you can reach LX&R by E-mail at email@example.com.
Reprint from "The Sun News"
See also: "A Revolution in Architecture" & LX&R Design Casting Page
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