We decided to build the railings using 1/2" conduit. It's easy to build, sturdy and inexpensive.
AND... the Frank Lloyd Wright sprite has made the journey from Chicago to Georgia. She has now taken up permanent residence at neoTerra.
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We looked at a lot of different ways to construct railings that would have a modern, minimalist appearance (see the How-To section). We both like the look of cable railins but the components are extravagantly expensive.
We decided to build the railings using 1/2" conduit. It's easy to build, sturdy and inexpensive. AND... the Frank Lloyd Wright sprite has made the journey from Chicago to Georgia. She has now taken up permanent residence at neoTerra.
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The interior is all sanded and painted. Next week the Electrician and Hero Heating and Air will finish up the electric and install the mini-split system. It will be really nice to have outlets and lights!
The taping crew was really fast. The whole house was completed in a couple of days. With the rain and high humidity it has taken several days to completely dry. We are using a portable dehumidifier to help dry the air. It runs continuously but its too small to be really effective. The downspouts are in. The corrugated tubing will carry the water down the slope and away from the house. We had torrential rain yesterday so we couldn't get the drywall delivered. To stay on schedule the good folks at Allsouth made a Saturday delivery for us this morning. It's really cool how they 'boomed' it in through the patio door by the kitchen. Getting all that rock into the house would have been a back-breaking job if they had to manually haul it up to the main level. We're on track for the sheetrock crew to start on Monday. Thanks Allsouth!! A blower door is basically an industrial fan mounted in a frame that fits into an exterior doorway. The fan pulls air out of the house which lowers the pressure inside. The higher outside air pressure causes air to flow into the house through all unsealed cracks and openings. The blower door unit has pressure gauges to calibrate the pressure difference being used for the test and a manometer that measures the total amount of air flowing in through cracks and openings. Air infiltration is measured in cubic feet per minute (CFM) and is then calculated as a number of Air Changes per Hour (ACH) Georgia currently utilizes the 2009 IECC (International Energey Conservation Code) which mandates that all new homes must have an energy audit and must achieve an air infiltration rate of 7 ACH or less. As I wrote in a previous post (Air Infiltration - How Tight is Good Enough), this is a pretty poor standard and we are aiming to do much better. The 2012 IECC standard sets a much stricter standard of 3 ACH or less.
Is it Cost Effective??
Based on the computer models, moving from ACH=7 to ACH=2 will save about 20M BTU of heating per year, which will save about $350 per year in electricity (neoTerra is all electric). This would be a savings of roughly $7000.00 over a 20 year period. On the other hand, spray foam insulation is expensive. You have all the cost and labor of installing batts and even more expense and labor for the spray foam. You essentially insulate the house twice. The spray foam is labor intensive since all of the windows and floors have to be covered in plastic and taped to protect against overspray. For neoTerra, the flash-batt system cost more than twice as much as just installing fiberglass batts. The fiberglass came to roughly $2.00 per square foot while the spray foam was more than $3.50 per square foot. At $7400.00 the cost of the spray-foam is sort of on the edge of being cost-effective if we only look at the savings on electricity. As an additional consideration, however, reducing the heating load by 20M BTU/yera allowed us to save about $2000 on HVAC equipment. My conclusion is that flash-batt insulation is cost-effective and will improve the comfort of the house. Insulation is a big factor in any energy efficient design. As I wrote in a much earlier post, air infiltration would account for about 40% of our heat loss if we used conventional insulation so we looked at ways to build a tight envelope. In the early design stage we looked at building with Structural Insulated Panels (SIPs). The SIP panels are typically made as a sandwhich that has OSB sheathing bonded to an insulating foam core. With SIPs you can construct very tight, energy efficient shells but the cost was just prohibitive. We also investigated using spray foam to fill the wall and ceiling cavities but the foam is very expensive. We decided to go with a "Flash-Batt" system. This technique uses a layer of spray foam against the outside walls to get an airtight seal and then conventional fiberglass batts, which are much less expensive, are used to fill the rest of the wall (or ceiling) cavity to get the desired R-value. The spray-foam creates a vapor barrier against the oustide wall. The system has to be designed for the specific climate to avoid having moisture condense inside the walls, which would create mold or rot problems. We used 1" of closed-cell foam in the walls (about R-7) along with R-19 Batts for a theoretical total of R-28. However, the 5 1/2" batts are being compressed into a 4 1/2" space so the actual R value is probably closer to R-24. The ceilings have 2" of foam and R-25 batts for a total of R-39. The basement walls are precast concrete panels from Superior Walls and have 2" of Dow blue board cast into the walls. Along with R-19 batts this provides a total R value of R-31.
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