In papercreters@yahoogroups.com, Greg House <ghunicycle@...> wrote:
In my opion papercrete would be structural as well as insulation. The factory made SIP's made with EPS are no more structural than papercrete would be, its the OSB that gives the sandwich its strength, the EPS or the Papercrete fills the void and assists with the structural and insulation value of the panels. I don't believe papercrete
has nearly the insulation value of EPS but in the right mixture I believe it would beat EPS in strength, as illustrated by Clair with her bullet test.
------------------------------------------------------------------------------------
There's another component to the strength of the SIP, the bond between the foam and the skin. If that EPS isn't well bonded to the OSB, I would expect it to have very little structural strength. Polyurethane foam can be cast in place, since it is naturally very sticky and expands, but EPS requires glue. That's another reason I wondered whether the PC panels should be made and dried before sticking the skins to them.
I got to thinking about my statement above and realized I forgot to include the nine little blocks I described in my first post. I really never described how these would be placed inside the two OSB panels, it would take two people to do it. One person on side holding a block over one of the nine holes, the other person on the outside placing a screw through the hole into the block, this will be repeated until all nine blocks are in place. Once this is done the top sheet can be attached to the blocks. My reasoning behind this idea is to keep the insulation machine from seperating the OSB, I have had the machine blow paneling or drywall off the wall of a house because the compaction so powerful. I also am interested in seeing if it will stick to the OSB, can't wait to try it.
I don't know if you've experimented with papercrete poured into place yet, but I'm wondering how well it would bond with your skins. I do know it usually shrinks away from forms people use for making blocks, which would indicate to me that the bond isn't too strong, so I'd be interested to see how your experiments work out.
I have not pour papercrete into OSB panels, and I know it shrinks away, that is why I may consider using Hydraulic cement rather than Portland cement, it swells while setting and maybe it would stop the shrinkage.
Bob
Greg
__._,_.___
