Forrest you bring up a lot of good points, I will try to address each one in the text of your message.
In papercreters@yahoogroups.com, Forrest Charnock fpcharnock@...> wrote:
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.
That was my first thought as how to make my own SIP panels, was to just build a one sided form and pour in a mixture of wet Papercrete, then I thought of how long it would take to dry and started thinking about other ways.
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.
You are complete correct, the strength of the SIP is the double OSB, the interior will serve as a little added strength and insulation value, not to mention fire retardnant and insect and rodent proofing the walls. True borax/clay mixture could be used instead of cement but I think you would have to pour these wet instead of blowing and I don't think steam would work on them.
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.
We here in Oklahoma are far removed from any rice hull resources, this could not even be an considered here.
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.
I have never assembled an SIP form, and I know there would be no room for error, but I have built several stick houses and steel frame houses in my time and I have also built furniture, so I feel confident I can build anything made of wood or wood composition with skill and professionalism.
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.
I looked at the site you posted below and was impressed with the work. But my idea for trying to prefect the method I'm working on is for speed as well as ICC approval. I have been, and still fill in for the City Code enforcement official here in my home town. I know what is expected for a house to pass code inspections. Above you stated I would have trouble running wire and plumbing in my panels. Not if I install the PEC for my plumbing and conduit for my electrical before I fill the cavities. It would be very simple to install both well in advance of filling the cavity of the SIP.
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.
I want to build my SIP in place right on top of the base plate, or I could build them all in another place and number them and then set them in place. Either way would work well and if I wait and install them on the base plate before I fill them they will be much easier to handle and the drying time would make no difference, they could dry inplace just as easy as drying somewhere else.
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.
I am hoping to build roof trusses and place them on 4' center and installing unfilled SIP's to them, spline them all together and once the roof is all installed, go back and blow in the pulp/cement/steam mixture into each. In this way the entire house will be an envelope of insulation. No need for attic insulation what so ever.
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 out 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.
I've been doing a little figuring as to what the cost of a double OSB, SIP would be. It goes like this, a single sheet of OSB is around $7.00 a sheet right now. (it will go higher in hurricane season) two of these would make the cost about $14.00 plus the top and bottom plate add $6.00 for that, that brings the cost to $20.00, if you make your own paperpulp thats zero, cement would add about $3.00 per panel, that would bring the cost to $23.00, add another $1.00 for broax, that brings the cost to $24.00, add another buck for misc glue, screws, nails...etc. Your now at $25.00 a panel I drew up a plan for a 12x16 out building it would require 14 4x8 SIP's @ $25.00 each for the walls. That figures out to be $350.00, home made trusses would cose about $20.00 or less each, placed on 4' centers would require 5 each. That would bring the cost to $450.00 install SIP on top of the roof would require 10 more SIP's @ $25.00, now the total is $1125.00, three sq of composition singles would run about $140.00 bringing th cost to $1265.00, a door and knob would run another $100.00 with trim. Thats $1365.00 of course there would still have to be eave fascia and gable fascia trim and a stucco siding. All in all the cost not including the slab or wood floor would be between $7.00 and $8.00 a sq ft. I personally think that is darn cheap. If you applied that same process to a house, I believe you could complete and finish the house for about $35.00 a sq ft. By todays standards of $75.00 to $125.00 here in Oklahoma, that is darn cheap. And it would pass ICC code!
http://www.esrla.com/shotgun/frame.htm
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