Papercreters: [papercreters] Re: Earthbag, Superadobe, Hiperdobe, why not Hiperpapercrete?

Thursday, March 15, 2012

[papercreters] Re: Earthbag, Superadobe, Hiperdobe, why not Hiperpapercrete?

Hi Jay,

I would be happy to post an update about that earthbag/papercrete home I started building about 15 years ago and completed three years later. We lived in it for about 6 years before selling it to live in Mexico for the next five years. Now we're back in Crestone, CO, living in a different house, but I have visiting rights to the old place and check it out quite frequently. Overall, the structure is as sound as the day I finished it.

I'm sure there were also a few cracks in the PC plaster that developed over time, but I never worried much about them because of the nature of the wall system employed.

As you know, the papercrete was used a plaster over the earthbags, both inside and out. After about a decade of exposure to the elements, the exterior PC plaster was showing signs of erosion in certain places, most notably at the base of the embedded glass where moisture would accumulate and on the more horizontal aspects, such as over the door eyebrows and the top of the vaulted entry way.

The folks who bought the house were concerned about this, and so was I since I expect that house to last for centuries. We discussed how to protect the plaster generally, and at my suggestion they went to considerable expense to have a professional stucco crew do a stucco job over the entire house, complete with more wire mesh embedded in it.

Papercrete makes an excellent substrate for almost any further plaster work, since it is so amazingly dimensionally stable under most any condition. The lime plaster I troweled over the interior PC has held up very well, and I expect the exterior stucco to do the same.

This does mean that the structure is not quite a breathable as it was with just the PC plaster, but I think it is sufficiently breathable, especially since it can still breath quite well inside.

I was always amazed at how well the combination of earthbags filled with scoria and plastered with PC performed as a skin for the house. At least in this rather arid environment there was never a drop of moisture that came through that package. I think that the PC acted like a sponge and just held the moisture at that level, allowing it to soon evaporate rather quickly. It was never damp long enough to develop any tendency to support mold.

I would never recommend that folks use PC as a solid material for a roof, either on a dome like mine, or on more conventional roofs. All of the major problems I know about (and there have been several of them in the Crestone area) where mold has taken hold, have been either in situations where the PC formed the roof or was in contact with the earth near the foundation. In several cases attempts were made to seal the roof with tar or Elastomeric paint or some such impermeable barrier, and these always failed eventually. Moisture would find a way to enter through small cracks and then get trapped into the absorbent PC. The moisture barrier would then effectively prevent the PC from drying out and in the warm interior environment mold is the natural result. One person saved his house by creating an elaborate tent-like structure over the entire house, with an air space between the two so the PC could dry.

I do know of a few instances of the use of PC as a plaster over strawbales, and this has also worked pretty well. The PC is naturally more absorbent than the straw, so it tends to wick any moisture away from the straw and actually help with the molding potential...at least that is my take on it.

--- In papercreters@yahoogroups.com, "JayH" <slurryguy@...> wrote:
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> Welcome to the group, Kelly.
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> Your home has been a topic of conversation on this group for years. Congratulations on doing such an excellent job with it.
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> Would you be willing to give an update about how the building is holding up? Have you had any maintenance issues? Any cracks in the papercrete?
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>
>
> Thanks for the kind words about the Hiperpapercrete idea.
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> I'm not certain whether or not the idea is brilliant. It's only brilliant if someone can make it work efficiently and successfully. I do think that there is potential behind the concept. That's why I tossed the idea out there.
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> As I alluded to, I think the concept would be of greatest benefit in areas where porous volcanic rock is not available inexpensively or locally. The more extreme the climate, the more important insulation becomes.
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> I think it is also fair to point out that the Hiperpapercrete concept need not be used exclusively. It could easily be partnered with other construction techniques.
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> For example, strawbale structures are also excellent insulators. As Bob Merrill has demonstrated, papercrete can be an excellent rough plastering system to fill in the gaps and quickly cover the bales, saving many manhours of labor stuffing cracks and hand applying rough coats of plaster or stucco.
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> Strawbale works best and easiest with rectangular structures. Yes you can make curved walls with bales, but it's rather a pain to fill in all the gaps, and the curved bale walls I have seen tend to appear segmented and blocky. It's difficult to get a nice graceful "sexy" flowing curve without a lumpy appearance or segmented flat spots.
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> Hiperpapercrete could be an excellent technique to create a curved wall as part of a strawbale structure. One or more curved walls can dramatically alter the architectural look and feel of a space.
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> Obviously if someone wants to blend papercrete and strawbale, extreme care would be advised to make certain that the water from papercrete operations does not damage the strawbales during construction. Wet bales are a nightmare.
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>
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> --- In papercreters@yahoogroups.com, "k1e2l3l4" <kellyhart@> wrote:
> >
> > I think that this is a brilliant idea! I have a lot of experience with both earthbag building and papercrete (see the house I built using both at http://earthbagbuilding.com/projects/hart.htm ). I can easily visualize making very substantial walls using the raschel mesh tubes (or even individual bags) filled with damp papercrete.
> >
> > Everything about this idea fits well with the physical needs of curing papercrete: the damp papercrete is held in place while it cures; the excess water can easily drain away; the wall can breathe on both sides once it is cured; the finished wall ends up being substantially reinforced and monolithic; and all of that mesh reinforcement acts to stabilize the wall against potential seismic forces.
> >
> > I'm sure that in reality it would be a messy proposition to be filling and placing that damp papercrete, but then working with papercrete tends to be a messy proposition period.
> >
> > If anybody tries this out, please let use know at www.earthbagbuilding.com or www.greenhomebuilding.com how it works out for you.
> >
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