Watershed Materials - Technology for New Concrete Blocks
The block with a smaller carbon footprint.

Blog - Watershed Materials - Watershed Block

Blog updates by Watershed Materials. Developments for sustainable new concrete block technology funded by the National Science Foundation.

Watershed One Demonstration House - Blocks to Top of First Floor

We're about three weeks into laying block with a crew of three masons, two hod carriers, a gofur, and a foreman. They lay between two and three courses of the double block wall per day. That's about 300 to 400 blocks. Before we started, I was planning on a little better daily production, but, not knowing much about building finished walls with rammed earth blocks, I hadn't factored the extra time that would be required to point the grout joints and keep the blocks clean. We're all really pleased with how the walls are starting to look. You can see for yourself in the photos.

When we reached five feet in wall height, we poured concrete grout into the cells. (Code requires filling cells every five feet unless you are willing to cut inspection holes in the bottom.)  We poured about 8 yards of six sack pea gravel with an 8" slump using a grout pump and a 2" hose. Figure one yard for every 80 blocks.

Back to laying block, we changed from an 8" high block to 6" at about 5'4" up the wall. Juliet's design is using the larger block on the bottom and smaller on the top to emphasize the weight of the base.  In addition to changing block size, we also rotate the blocks every two feet up the wall to play with the pattern even further.  In mason's terminology, this would be a "soldier course". You can see both of these patterns in the photos.

The electrical is a real challenge. Although I had originally planned to surface mount all of the conduit and boxes in the garage and mechanical room, I decided to try putting the electrical in the blocks themselves, knowing that we'd have to figure out how to do it by the time we got upstairs anyway. It takes working carefully with the masons, because your horizontal conduit lays into the notch in the bond beam blocks and you only have one row of bond beam blocks every two feet up the wall. As a matter of fact, installing the rough electrical requires so much time on the job in order to coordinate with  the block work that I'm doing it myself, along with the block crew foreman. To install a box we cut notches in the blocks (half a notch in the lower block and half in the upper) and connect the boxes to one another with the conduit. We run vertical conduit up through the cells to glue to as the wall rises in height. 

On Thursday we set the first of the steel lintels. Our standard lintel is T-section fabricated with a 3/8" x 15-3/4" plate steel for the head and a 3/8" x 6" stiffener welded in the center. The lintels extend 8" beyond the openings and sit directly on the jamb block, glued down with adhesive. The big garage lintel was more substantial: an 8" I-beam with 3/8" x 15-3/4" plate steel welded to the I-beam flanges top and bottom. We drilled 4" diameter holes in the top and bottom plate and inserted 4" steel pipe nipples through the holes so that the grout and reinforcing would be continuous through the beam.