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The tire cistern walls and the bond beam are complete. For details of that part of the process you should view the Tires or Bond Beam pages.
The next phase of construction is to apply the cement infill to the interior of the cisterns. This is similar to the adobe infill process used inside the house but you use concrete instead. This gives
the cistern more strength and also protects the tire wall from the porosity of the cement. There will be a very slow and steady movement of water through the cistern.
Very slow!!! All cement containers be they tanks or boats pass some moisture.
Below we are starting on the first layer of cement infill.
You can see the redwood plates embedded in the bond beam. These will be used to attach the cistern lid. You can also see the PVC overflow pipe protruding through the bond beam.
The concrete infill takes many more layers than the adobe. The adobe has more body and is %500 more sticky than cement. Gotta be patient. Below we are ready for the last layer of infill. If
you look closely in the bottom left corner of the image you can see the outflow pipe. It was placed under the first row of tires. Seems like a long time ago! Don't forget to put these in when you
first start!
We are now ready to start installing the stucco netting. This requires at least two people, three is even better. We used 3 foot wide rolls. Don't get the really long rolls because you have to
man handle them a lot and the long rolls are heavy! Start at the top of the wall, run the roll down the side along the floor and up the other side, cut. Attach it in a few places, just enough so it
stays put. Then start at the top again overlapping the first run by half the width, run down the side, across floor, switching overlapping sides in the middle, then up the other side
maintaining at least a one half overlap. Its like your making a big X with two runs. Then start again overlapping half way on the last run, do this until you have the entire cistern covered with two
layers of netting. The floor will have about 10 layers, the important thing is to get at least two layers on the walls. Now you can start attaching and stretching the wire all over. The tighter
the better. We used galvanized wood screws and roof discs to attach the wire to the tires and cement. Also to the cans in the bond beam around the top. Below we have just started to stretch the wire.
Here's a picture of the east cistern ready for plaster. You can see the outflow pipe on the right. It is a 4 inch PVC pipe with a toilet flange attached. The plaster will be applied to come flush with
the flange. The a plate with a hole in the middle will be bolted to the flange to seal the connection. You can see it takes a lot of screws/disks to get the wire tight and flat against the wall.
None of the pictures of the plastering process came out. There was not much to show, just keep putting layers of plaster on until your really tired of that job! You apply a 1/8 to 3/32 inch layer on
and scratch it. Cover the top with black plastic. Spray with water every 8 hours or more to keep it damp. Let it cure for two days before applying the next layer. The plans called for 4 layers. I
had decided on 5 for a little insurance. For some unknown reason the 4th layer cracked. Bad sand, cement, water?? Who knows, but I increased the number to 6 layers. The last layer you apply smooth.
Two weeks after the last coat we installed the lids. The lids are made from a "Silt Hub", see SSA drawings. You cut out pieces of galvanized sheet and rivet the sheet to the hub in a cross pattern.
Then set the lid on the top of the cistern. Be sure to get it level so the weight of the lid is evenly distributed around the perimeter. We screwed the lid into the wood blocks with corrosion resistant
screws. Jim at SSA said you could put them on with 4 or 5 guys. I'm glad we had the tractor, those things are very heavy!
When you install the lid its not yet complete. You have to cut out 4 triangles and rivet them to the lid to complete the circle. You can see the 4 voids in the lid below we just installed behind the
partially constructed systems package. It doesn't look like there is much of a slope from the cistern edge to the silt hub(big red pipe in the middle) but there is a 3 inch drop on this lid. You can
see the over flow pipe on the left side of the cistern protruding through the bond beam.
After riveting on the 4 corners its time to paint the lid. I made redwood silt hub lids to cap off the top and Jan collected local volcanic rocks to circle the silt hub. The rocks are your first filter
in the catch water system.
The last part of the cistern is the north parapet wall. This allows you to bury the house a little deeper and also provides a solar reflector to help melt snow and ice on the cistern lid during the
winter. I can vouch for its effectiveness. Donut leave this option off you r must list f you have cold winters. It helps a lot to paint the wall a dark color. The parapet wall below is under
construction. You run the wall out to the side. Leave a small opening just above the over flow pipe. This is the over flow in case it rains so hard the silt hub cant pass the water fast enough
and the lid fills up. Its also a emergency overflow incase the regular pipe overflow plugs up. You can see the pipe just below the opening between the parapet wall and where the hut roof
parapet joins the cistern.
There are more pictures of the cistern lid on the Systems Package page.
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