Passive Solar - Its more than pointing the home south.

I was speaking with a friend who is planning to build a "passive solar" home off the grid. The plan is stick frame 2x6 walls, point the home south, cover the south wall with windows and sit back and enjoy. I asked them about the floor and the plan was to lift the home off the ground and use a crawl space. I asked them about their overhangs for the south and they hadn't thought that out yet. Although this home may meet there needs, as similiar home designs meet the needs of many people throughout the world today, to me a few simple changes could make this home REALLY efficient and comfortable. I will touch on a few of those in my next few posts including thermal mass, trombe walls, overhangs for south facing homes and glazing to livable square footage ratios.

Next Adobe Class

I am excited to head down to Bosque, NM to attend the second of two classes put on by the SWSA school. This will be a hands on class, where we will have a earthblock press (AECT manufacturer) available. We will be covering rubble trench foundations, CEB building, slurry's, running electrical, bond-beams etc. This should be an exciting class. I will be taking great notes and sharing them here.

Kim and I have also been trying to figure out our ultimate plan. After attending the last class I was afraid our first guest house was too big, even though it was small. I was sitting in the hotel and I was thinking "you know, if our first house is a guest house, then it doesn't really need to be much bigger than this room" so......I redid my guest house plans and made it 24x24, which is the same size as the detached two car garage I just built here in KC. I removed the laundry, made the bathroom a little smaller and pulled out the kitchen. Now I am worried that if I get the guest house built, then for some reason I can't build the main house, we won't have everything I need in our first and at that point only house. Decisions, decisions.....

Point Loading - Uniformity is Key with CEB

One of the attractive aspects of CEB is the fact that you can use a thin slurry to lay them, rather than a thick mortar joint. As I continue to explore building with CEB, I have determined that uniform block height is essential if mortar joints are not planned to be used. Eliminating mortar joints, like those used with Adobe, Brick or cement block, reduces the amount of skill and labor required thereby enabling the DIYr and saving resources.

As CEBs are layed/stacked, and courses rise, the blocks in the lower courses, experience increased downward pressure. If the blocks are flat against each other, or if they sit in a "bed" of mortar allowing them to lie flat, then the downward pressure in any area of the horizontal block faces is fairly equal. As mentioned equal pressures occur due to either 1) a mortar joint, or 2) uniform block height.

Since one of the benefits of a CEB wall is a thin slurry set thereby reducing labor and skil, uniformity then becomes key. If blocks are not uniform in their height, then as courses rise and downward pressures increase, the chance for "Point Loading" increases. As shown to the left, point loading occurs when one specific point or area of a higher coursed block carrys more of the dowward force due to a non-uniform lower block. The lower block has only one "point" that it is in contact with the upper block.Carrying the forces in this one area, and not spreading the load across the face of the block, can cause the block to crack or fail, thereby eliminating the effectiveness of the wall.

My next post with focus on two methods used in block production, vertical and horizontal pressing of the block. Each has pros and cons when it comes to their effect on Point Loading.

Finished Solar Adobe Class

Well I finished the Southwest Solar Adobe Class, taught by Joe Tibbets. It was a very informative class. I met quite a few people who are looking to build with adobe and / or compressed earth and was able to start to test some of the soil from our site in Taos, via the shake test and golf ball test (for lack of a better term). I also learned how to determine True South, so you can orient the home correctly, learned about a Speed Leads and also determined how to figure out Sun Angles so you can then determine placement of windows and length of overhangs. I have updated the main site with much of this info already, but will be expanding and reiterating it here as well.

Heading To Taos

Well I am heading to Taos this weekend, specifically to Albuquerque to attend the first of two classes taught by the Southwest Solar Adobe School. The class is their Passive Solar Home Design class. It will cover the design of adobe / compressed earth block homes, specifically going over the NM building codes for compressed/rammed/adobe earthen homes.

After the weekend is done, I will be staying in Taos, on our new property, scoping it out, taking picture, meeting with the Taos Planning/Building department to determine next steps etc on obtaining a building permit. I will also be digging up a couple hundred pounds of earth and will be taking that to Powell and Sons, just north of Albuquerque. They manufacture compressed earth block machines. Compressed earth is how I plan to build our homes. I spoke to Bill Powell and he agreed to compress my dirt from onsite so we can see whether the onsite earth is of the correct make up to use in a compressed earth home.

I initially started my plans and design using earthbag construction as the method. After I realized I wouldn't be able to simply take time off work to build the home in one fell swoop, I realized earthbags might not be the right method for me. Earthbags won't allow me to stage the building of my property. I can't fill them, then come back a year later and stack them, really. If exposed for too long, they will deteriorate and I can't gaurentee that I can keep them covered. This requirement, along with my requirement to use earth, pointed me to stabilized compressed earth. Thanks and I'll share more later. You can also find more at my primary website, ourTaosHouse.com