The making of a high performance green home on a budget - Framing, Rough-Ins, Insulation
For this home, concrete block was chosen for exterior walls. The materials and manufacturing are local and the cost is effective. SIPS (Structural Insulated Panel Systems) claim faster building times, less material waste, higher “R” values, and easier construction but I have not found this to be true. Concrete block is readily available, strong, can be fitted with insulation superior to most SIPS, can be completely recycled locally, and can be installed in just a few days. It is also about 15% cheaper than most SIPS. In some instances certain SIPS systems are superior but this was not such an application. The walls took just four days to install including the concrete beam work. All concrete and steel was recycled locally.
Engineered, open webbed roof trusses were installed. These trusses are designed to be as strong as possible while keeping material use at a minimum. Our trusses are treated at the plant with a proprietary boric acid product known as Frame Guard. The plant is local. Frame Guard is easily recognized by its green color. It is designed as a moldicide to prevent the growth of mold during the construction process and beyond. Boric acid also deters wood boring insects and is completely harmless to people. In fact, it is often used as a wash agent in the eyes of newborn babies.
The roof deck is constructed of a product called ZIP-Ply. It is made from wood chips much like OSB. However, this product uses glues that are far superior to ordinary OSB. It is rated for direct exterior exposure. This is due in part to the pre-applied exterior membrane. This product is Miami-Dade rated as an approved secondary moisture barrier. If the primary roof ever blew off in a storm, this product would protect the home from moisture damage. Most homes utilize a nail down felt sheet that will blow off in a storm. This extra protection adds to the durability of the home and allows for a reduced home owner’s insurance rate. It also reduces materials and labor.
For interior framing, we utilized a locally sourced white pine framing, and treated with Borate where necessary for moisture exposure in wet walls and in contact with concrete. Low waste factors were used to ensure that nothing was wasted. Also, we used stacked wall construction to reduce the length requirements in the lumber. This saves money and materials without affecting quality.
High efficiency vinyl windows with LOW-E, insulated, impact resistant glass were installed. The doors were of the same variety. All of these were sourced locally. Impact resistant glass is superior to protective coverings (shutters) for several reasons. Impact glass provides for an insurance discount, offers constant security, and protects your home without fail. Shutters only work if you’re there to install them and offer no insurance savings. I will only build with impact glass. The investment into these superior performing windows is quickly recovered through energy savings and insurance discounts. Not to mention piece of mind and comfort!
Electrical rough-in included pre-wire for fluorescent lighting in all closet and utility applications. Switched circuits were used for LED rope light to provide ambiance without using much energy. All other lighting will be CFL or LED. There will be no incandescent or halogen lighting in this home. Bath fans were wired for timers to ensure that they are not left on longer than necessary. This home also includes a full structured wiring package and alarm pre-wire. The panel is ready to accept an inverter for a future installed solar PV system.
A solar hot water system is installed on the lighter colored roof shingle. This will provide all of the hot water to the 80 gallon tank located in the garage. A single valve shut-off for the washer supply is used to ensure easy shut-off in case of a flood. The utility room is located adjacent to the garage to control washer flooding if it ever occurs. Access to all in-wall valves has been framed for future service.
The HVAC system was sized by a mechanical engineer. In spite of this home’s size, only a 1.42 ton air conditioner is required to service this home. A 2 ton, 2 speed system using 2 zones is installed. It is a 20 SEER, Puron system by Bryant Evolution. All duct runs are centralized with remote returns. The entire system was sealed at install to ensure no construction debris enters the ducts. The air handler is located in a serviceable attic that is completely sealed and insulated. This will allow the system to operate at its peak efficiency. This system is tested by a third party using the ‘smoke test ‘ standard. It is a prerequisite to the Energy Star certification.
The exterior walls use to separate insulating systems. The primary is a Tri-polymer, urea-formaldehyde free, non-expanding foam. This will provide an R-10 factor. The second is perforated radiant barrier providing R-4.1. These systems are healthy, effective insulators that do not create a vapor barrier. Vapor barriers in FL create prime opportunity for mold growth. Foil-faced rigid insulation is such a vapor barrier and it only provides R-5.
All overhead insulation is R-21 Bio-Based sprayed foam insulation in an open-cell configuration. This creates a cool attic allowing for a better climate for your duct-work, and a cleaner indoor air quality. It also makes a really tight home. In fact, it is so tight that we use a ducted fresh air return for the HVAC system to keep the home’s pressure balanced! The insulation barriers are tested to the ‘Thermal By-Pass’ standard as a prerequisite to the Energy Star certification. We also created a barrier to the roof at the garage to prevent possible air contamination from vehicle exhaust.
All interior walls adjacent to common areas are insulated using a formaldehyde-free, healthy batt insulation to control sound. This feature is important to the livability and comfort of the home. All slab penetrations were sealed using a no-VOC sealant.
Interior considerations were made for pest control as well. The bottom three feet of all walls were treated with Bora-care, another boric acid based pest control designed to combat termites. All other lumber in the home is treated with Tim-Bor, a boric acid product designed to combat wood boring insects, and dry-wood and Formosan termites. For ordinary pest control we installed the Taexx system. It is a system of perforated tubes run in the walls. A mounting valve on the exterior of the home allows a pest control service to treat your home using EPE exempt products without even being home. No more baseboard spraying!
Drywall was installed on June 20th! We started digging on April 16th. How is that for efficient? Stay tuned for more. I will be finished by mid-August.