Milestone Complete: Construct Demonstration Unit

And there it is...Our first CEB structure. We now have a bodega and will be expanding as resources allow. I have to thank my friend from Colorado who came down for three months to help me build this. Making the blocks was a group effort but the actual construction was done by two guys and very basic hand tools. Without the help of J from CO it would not have been possible to do this year. Waiting until next year would have been a big bummer so it's really great to get our rainy season test underway. Future direction will involve testing various new techniques such as lime plasters and arches and ramping up steady block production.

Presenting the Screen-O-Matic 2000!

Total materials cost was around $50. We needed a screen that was purpose built for CEB needs. For us this meant portable, low cost, manual powered and a significant improvement over the way we have been doing it with smaller two-person screens. With the previous method 5 guys produced enough soil in one day to make about 100 blocks. With this new tool one guy can produce that much.

Still More Detail...

Top photo shows how we decided to put in the lintel for a door. We left loose half blocks in place when we poured the columns and later removed them and put the 4x4 in. We did have to chisel some out on one side still and then back fill it with mortar mix.
In the second photo you can see where we stopped the stucco and the 'espera' for the iron gate. It's sunk into the poured column behind it. We deliberately left the inside of the wall unfinished for demonstration purposes.
Next you can see the basic roof technique and the finished stucco (still drying). If you're wondering what the two pieces of zinc below the main level of the roof are for, it's just where we decided to store the extra pieces we had :-)

More Details on the Techniques

Here you can see more of the bonding techniques. The top photo shows a close up of the wall with the mortar joints. The color is from a basic broom wash that was done as it was being laid up. Next photo shows where we have started the stucco (repaya). In the bottom photo you can see how the formed column at the end of the wall is used to join the CEB wall to the pre-existing brick/cement wall. The blue color on the existing wall is old paint. The darker blue color on the concrete column is a bonding agent (plastibond) we were testing.

Our First Building

I love tests that might also have a practical use. As long as your planning takes into account that it's just a test (and dependencies are mitigated) any benefit derived is just gravy. Therefore, we thought a bodega would be a great first building project since we needed somewhere to put our stuff and it incorporates numerous conventional construction techniques that we wanted to experiment with.
The most critical test of all is the water/weather proofing. The rainy season in Nicaragua is torrential and will be the biggest challenge we will likely have as far as the CEB process goes. In that regard we needed to test techniques for the footer, roof and stucco. Ideally we wanted to go with a lime stucco but learned too late in the project that the lime needed to hydrate for a longer time than we had. To compensate we went with a standard masonry stucco using 6:1:1, fine sand, lime, cement. You can see we used cut stones (about $1.50/each) for the footer on top of an existing slab. This got us a foot off the ground and is working well so far. The roof could use more overhang but still is giving the coverage needed. We used all plain blocks bonded with a standard masonry mix.

An Odd Atmospheric Display

The day of this photo (Mid May) we got to see an unusual halo effect around the sun.

A Change of Plans

We started with the intention of doing a completely new structure. The plan was for a round room of about 12 feet with a concrete/rebar footer and a poured concrete/rebar slab roof. While we still love the idea we realized that we weren't going to have the resources to pull it off before the rains started (time and money being the constraints) so we changed tack and decided to go with the original plan which was to build off an existing structure, a brick outhouse. We had a pretty good design worked out for the round room and were excited about doing it but it was just too ambitious for the first room in a number of ways. In hindsight it was much better to simply extend off the front of the outhouse as it put us back in a realistic time/money budget and also allowed us to test basic construction techniques without too much risk exposure.

Yet More Blocks

We realized it was going to take a few more blocks to get the bodega done so we got busy. It is so nice to see the stack grow.

After a long time with no updates...

I have been remiss in updating in regards to the progress of things, I know. We have been in a race against the rainy season. Since the last posting we have been working on the first building (a bodega) made with the blocks in the previous photos. The rainy season starts in Nicaragua around the middle of May (give or take a few weeks) and we had to get the roof on the bodega before then. Two days before the rains started we finished the roof. Now that the time pressure is off I can finally bring the history up to date.