Papercreters: Re: [papercreters] Re: Structural Insulated Panels

Monday, February 23, 2009

Re: [papercreters] Re: Structural Insulated Panels

One way you could try is build a form the size of the SIP and pour it and
then add the OSB as was mentioned.
My question is what is it you are trying to accomplish? The strength of a
SIP is in the skin much like a straw bale wall's strength is in the plaster.
I don't see why you need any cement for an SIP. If you used borax and
possibly clay as a fire retardant you could make a form and pour a paper ,
borax/clay mixture into fairly dry and leave it a bit proud of the form.
Then shave it flush is needed. You have enough strength in the skin alone
but you would be surprised how strong the paper is without cement.
Personally I think you would be better off building a modified stick frame
and in filling it with rice hulls than do what you propose. Of course this
would work fine with papercrete or simply the cellulose. One huge advantage
of a modified stick from is you can allow for as much in fill in the floors
, walls , and ceilings as you like and imperfections in thickness would not
be as critical as with SIP's. If you have never assembled SIP's I guarantee
you there is almost 0 room for error in thickness or the panels will not
join properly and you could be in serious trouble and waste a fortune in
time and money.

The modified stick frame is super wind resistant. All you have to do to
build one is lay out 2 2 x 4's flat on the table and get some scrap OSB
board or plywood cut in 12 inch squares. [or whatever you want the
inside thickness of the wall to be] and using an air stapler attach one at
the top , bottom and center. there will be a 5 inch gap between the 2 x 4's
as they are 3 1/2" wide to run your wiring and plumbing which you won't
have with the panels.
Just build your wall trussed in the garage and then lay down a double
bottom plate -2 x 4 's 5 inches apart and nail them up and attach the OSB
skin to one side and the exterior siding to the other which saves half
the OSB and the labor to nail it up. . You can fill the void with rice
hulls and no fire retardant is necessary ,, and the insulation value is
similar to cellulose.and because it does not pack will remain working
without having to add more.
It cost 5-10 dollars a ton. A ton will fill a little over 200 square feet a
foot thick and give you about an r-32 . You can also build floor trusses
the same thickness and the ceiling the same or a bit more. Of course you
could use paper to in fill but the cost of the fire retardant will raise
the price . Both are waste products . It adds about .45 a foot to your
framing cost and it eliminates the need for a vapor barrier . .The outside
skin can be cement board or you could use the latex paint and cement
slurry over chicken wire or fiberglass screen. Of course you can use brick
or wood etc.
If you build the roof trusses without an attic you can use metal roofing
with no decking. Personally unless I was going to make bricks our of
papercrete I think the stick frame rice hull house will be cheaper and less
labor by far and the codes people should be okay with it, it is a proven
method.