I did a little gross calculating and have determined it will take two mixer loads to build each papercrete wall panel. The mix of choice is:
160 gallons of water
60 lbs paper (newsprint)
65 lbs sand
94 lbs (1 bag) portland cement
Two batches should give me a panel that’s a little over 6″ thick. I will have to find something to do with any leftover mix. I will also have to figure out how to make sure all the panels are the same thickness. The panels all have different window and door configurations, so this could get interesting.
Because I am using only 16 bags of portland cement for the papercrete (2 per wall), I may want to use white portland for the first layer of each wall (the portion of the wall that is inside the building) and regular portland for the subsequent mix layer. That would give me lighter brighter walls inside allowing me to use a latex wash on the walls instead of actually applying layers of paint. The inside colors would then be brighter and clearer without the gray cast of the portland cement.
Using papercrete does cause a problem. Because I need an expansion layer between the papercrete and the ferrocement layer, and because I can’t cover the papercrete until it’s dry, push through connectors aren’t going to work. I can’t lay the EPS over the wet papercrete or drying will be inhibited.
In searching the net for nylon screws I hit on a neat thing! Threaded nylon rod, a 12″ length for $1.50! With 1″ EPS, I can take a 12″ rod, cut it into 3 pieces and push the nylon into the wet papercrete so it protrudes enough to go through the EPS and lock into the ferrocement layer. Poof, instant push through connectors. I can even spin nuts onto the end if I think I need a little more grip, around the outside edges or on the corners, for example. 16″ centers is probably too close for my app. 16″ on center is structural, and I don’t need structural. I just need everything to be held together until I can get the walls up and fastened together. 30 connectors per wall should be adequate. That’s 10 nylon rods, $15 per wall for connectors. Wow! I bet I can’t get any fancy connector for anything close to that price.
Now I just need to figure out how to keep the connectors upright and in place as the papercrete dries. I’d like to be able to put a *weight* on the form to add some compression while it’s drying. Not anything heavy, just something to help with the initial leveling to give me a more uniform layer. I’ll have to think on this some more.