Post date: Aug 19, 2015 12:18:48 PM
Installing drywall generates a lot of dust. I would estimate that in one day we could fill a bucket with gypsum dust — all made when we cut the drywall around doors, windows, and electric junction boxes.
Fortunately, gypsum dust is not toxic or abrasive, and it dissolves in warm water. So, though most of it falls on the floor, a lot of it gets into our hair, clothing, and skin. But it also washes off easily. Using soap doesn’t really help, because the calcium from the gypsum (hydrated calcium sulphate) combines with the organic part of soap, creating an insoluble substance. Once the gypsum has washed off with water the soap works again.
I provided ‘technical assistance’ to a gypsum wallboard mill once. I didn’t really help, because the plant engineer had that place running efficiently and smoothly, but I did learn a lot. The gypsum rock is ground to a powder, then heated in big kettles to drive off the water, forming plaster of Paris. The plaster is recombined with water, poured between two sheets of paper (made of recycled newspapers), and rolled onto a conveyor belt where it quickly sets, cut into lengths, an dried in a hot-air oven. This forms rock again. Thus the name 'Sheetrock'.
My building crew tells me that the dust we will generate when we fill the holes and cracks in the drywall (taping and mudding) will be even more that when we install the drywall. I can hardly wait. Whereas I am not strong enough to lift the drywall into position, and my electric screwdriver is nowhere nearly as fast as the pros, I can tape and mud — or at least I think I can. We’ll see.
Meanwhile there always seem to be plenty of supporting work while four guys are installing drywall. There are cutoff pieces to get out of the way (so the scaffold rolls without bumps and no one trips), pieces to hold while being cut, materials and equipment to move out of the way as we move through the house, and lots of dust to sweep and vacuum. And the fine dust plugs the filter on the vacuum cleaner, so the filter requires special cleaning daily.
Meanwhile Jake was forming the shower pan. This is the sloping floor under the tile that directs the water into the drain. The method for creating this slope seems really primitive to me. When we poured the floor slab we depressed the shower area by three inches. (It seemed to me at the time that we could just have troweled the concrete in this area to slope towards the drain.)
The plumber lined this rectangular area with a leftover piece of the roofing rubber, then flooded it for the test. (It did not leak.) When we pulled the plug after the test, water pooled in part of this area, because the floor sloped the wrong way. So we took the rubber liner out (partly to avoid damaging it).
Next we put ‘dry pack’ concrete (actually a mortar made with less water — not really dry) into this hole to form the right slope towards the drain. Eli wanted to raise the lowest point one inch, but Ray the plumber explained that he could not just lift the pipe to the level of the concrete pan and that would result in wrinkles where the rubber liner dipped to meet the sewer pipe.
Eventually the plumber removed his pipe and raised it so Jake could form the pan higher. Next is to re-install the rubber liner. Finally we have to put more ‘dry pack’ concrete above the liner so that the mortar that holds the tile will have something to grip.
There is a more modern system. A company (Schluter) sells a preformed plastic pan plus a waterproof sheet material. The tile mortar will adhere to this special sheet. It costs a little more than the dry pack method but saves labor.
Past is past. Today we should be able to re-install the rubber liner, test to ensure that water doesn’t leak or puddle, then add the second layer of ‘dry pack’ concrete to bring the shower floor up to the level of the rest of the bathroom. (My shower will not have a curb.)