Watershed Materials - Technology for New Concrete Blocks
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Blog updates by Watershed Materials. Developments for sustainable new concrete block technology funded by the National Science Foundation.

Watershed One Demonstration House - Blocks and PISE

We started the week by grouting the block cells on both of the buildings: the first four and a half feet of the kitchen/family room wing and the first five feet of the bedroom wing. The non-retaining block walls only get the outside cells filled; retaining walls we reinforce and grout both the interior and exterior cells. We poured nine yards of six and a half sack pea gravel with a nine inch slump. I decided to increase the cement content by half a sack because we were increasing our water content to get better flow. Here are photos of pouring grout, one for the kitchen and one for the bedroom.

After we finished the pour (Monday around noon) the masons went right back to work laying block:  two masons on each building.  We also added another laborer to make sure we had enough man power to keep both the pace and the quality.  Here's the kitchen crew at work.

One other task scheduled for the week was the retaining wall for the bedroom wing.  It had been my intention at the beginning to build all the retaining walls out of shotcrete, directly against the excavated banks, but you will remember that the retaining walls for the garage and mechanical room were double block.  That was because our excavation wasn't precise enough to get the cut banks close enough to the building lines, so it's only this one back wall of the bedroom wing where we are getting the opportunity to try out this method of shooting against the bank.

I talked to several waterproofing specialists and spent a great deal of time researching waterproofing on the internet before I was confident moving forward.  What we settled on was this:  First we shot a low-cement pise against the cut to fill in the over-ex and create a straight, flat wall to attach the waterproofing.  The geo tech called it a vertical controlled density fill (CDF) to "true the bank"; next we laid a four-inch perforated drain pipe in a filter sock on top of the footing;  onto the CDF wall we nailed a drain mat, followed by a protection board, and then two layers of Laurenco bentonite-impregnated rolled waterproofing with mastic between the sheets, activated with a torch.  Here's a photo of the mastic being spread onto the sheet.

Next we tied a double reinforcing mat of #5's and #4's at 16" each way, set our guide wires, laid in supply and waste lines for two bathroom lavs, installed electrical boxes and conduit, shot a structural wall of sand and six sacks of cement, and finished with a pise veneer of site soil and three sacks. Here are a series of photos from the shoot.

By Friday the masons had finished the walls for the kitchen/family room so that we'll put the clerestory trusses on next week.  The retaining wall is finished to its full height and the block walls are up to about six and a half feet.  We took up the plastic and plywood protecting the kitchen slab and from now on we'll use tarps to keep it clean.  The last photo shows this floor and the blocks to 6'-8", two windows with their steel headers, and the four tall windows in the family room.