My new rule of thumb (learned by trial and error): In construction, everything costs three to four times as much as you expected, and takes at least three times longer that you thought it would. :)
After all the rain finally dried up-- and in order to be able to plaster the house-- we had to get the roofing material onto the roof (another project Michelle helped a lot with).
The roofing stuff was estimated to cost $1400.00-- we had exactly $700.00-- a generous gift from our church-- but still only half what we needed. Murv set to work figuring out how to make it work! He is great at that, and by his genius and some miracles-- he figured out other materials he could use and came up with a system that works great!
The material we used is called TPO (Thermoplastic polyolefin membrane)-- It's a white reflective membrane that cuts a lot of heat (keeps the inside of our cabin nice and cool), and does not off-gas-- making it a great roof for suntanning, living roofs (growing plants!), and rainwater collection-- rainwater collection being a very important part of our sustainability plan.
We got up on the roof just the other day to enjoy the sun and it was like being in a tree house and at the beach with no sandy mess. The breeze was blowing in the treetops so that it sounded and felt like being at the ocean. The roof surface was comfortable and cold to the touch even though the sun was beating down on it, yet we bot got some great sun exposure. It's really amazing stuff! Not to mention now if it starts raining again-- our bed will never get wet again!!!!!