Gail of Green Living

GREEN Medical Center Home For Sale: The Building Envelope

3703 Drummond

This is the third in a series of posts regarding the above property for sale in the Medical Center neighborhood called Braes Heights, in Houston.  This owner/builder has researched and studied so many products and methods of green building, that I’m sure we can all benefit from his research.  This week I’m summarizing his research on The Building Envelope, the backbone of  The Building System.  This is where the outside environment conflicts with the inside.

Traditional builders still use the wood framing method, which falls short in regard to durability (termites, wood rot, mold), and it requires added insulation.  Steel framing is quite expensive, and it’s difficult to find people who know how to do it.  It also requires insulation.  Thermal bridging is an issue with wood, and more so with steel.

SIPS (Structural Insulated Panels) are easy to manufacture and provide good insulation and strength.  They can be made to various sizes with window openings all pre-cut.  They are easy and quick to assemble.  The roof system can also be SIPs, with modest trusses, allowing for open and attractive interior spaces.  They do not suffer from thermal bridging, which is another plus.  The downside of SIPs is the fact that they limit the design of the home to a simple gable design with relatively few corners.

ICF (Insulated concrete forms) have been around for fifty years.  There are lots of manufacturers and this construction method is widely used in Canada and some northern states.  It is extremely strong, with 5″ foam insulation sandwiching 6-1/2″ of reinforced concrete.  Convection is not an issue and no termite wants to eat it.  The R-value of the system itself is about 25.  But when you take into account the thermal mass, the lack of convection or conduction and add in the radiant barrier/moisture barrier and air spaces, plus the exterior finish (stucco, stone or brick) and the sheet rock on the inside wall, the number is probably more like R-50!  There are no seams like in the SIPs system.  And a 14″ thick wall makes for a quiet home.  OK, this ICF has massive strength, the thermal mass, resistance to heat movement, sound dampening, resistance to convection moisture, bugs, wind, fire…so this is what makes sense!  The additional cost was $3/sq.ft over the cost of wood framing…amazing difference it makes!  They found a company in Texas that makes the product, BuildBlock ICF, and their service and reputation are first-class.

The roof information in my next post will amaze you!  Meanwhile, if you would like to see more photos and details of this beautiful home, click here or contact me for a personal tour.

GREEN Medical Center Home for Sale: Principles for the U.S. Gulf Coast Home

3703 Drummond

The United States Green Building Council’s Leadership in Energy and Environmental Design for Homes (LEED-H) program looks at home building from a broad view.  This program looks at where the home is built, (Braes Heights near the Texas Medical Center in Houston, TX), and how, and with what materials it is built.  The LEED certification process requires site management, recycling and waste management during construction.  Credits are given for energy efficiency, water conservation, air quality, product choice, etc.  The top rating is Platinum.  The guiding principles for a U.S. Gulf Coast home involve “what makes sense” in regard to the following features:

Strength and Durability:  This basically means “hurricane resistant”.  The storms bring wind water and utility failure.  Walls, windows and the roof are the core of the strength of the system.  Utility failure, which lasted up to three weeks after Hurricane Ike in 2008, dictated they include backup electric power and water.  Durability also applies to a longer term without maintenance issues.  The builder pursued the “Fortified” rating from the Institute for Building and Home Safety.  This is awarded to homes of exceptional strength and threat resistance.  This home was engineered to withstand winds 20 miles/hour over the FEMA wind speed zone designation for this location.

Efficiency:  This is in regard to energy in vs. energy out.  “Energy in” means solar electric and solar thermal.  “Energy out” is the sealed building envelope, immense insulation, and radiant barriers.

Security:  Keep out the boogie man and keep your stuff in!

Livability/Health/Comfort:  This category addresses air quality, humidity level, choice of appliances, lighting and finishes, and even the bathroom exhaust fan.

Affordability:  Understand there is a cost to buy and a cost to operate.  This is where “what makes sense” makes sense!  The owner shared with me that this home’s costs were about 20% higher than a traditional home, and I think much of that extra cost is recovered in energy savings, longer lived appliances, especially those with water that is pure as this system provides.

Green:  LEED-H Platinum was the target goal.

Next week’s blog will reveal the details of the building envelope, the backbone of the Building System.

If you would like to know more about this home, more pictures and details can be found here.