THE THERMAL ENVELOPE

The building envelope has long been overlooked and addressed uniformly throughout different climates. We now recognize that climatic conditions greatly effect how we should build the “box”. The latest research has led to newly applied perspectives in Building Science, primarily the Thermal Envelope.

The 1997 ASHRAE HANDBOOK (23.10) recognizes and endorses this procedure in hot, humid climates.

The 1887 Florida Energy Code also prescribes Thermal Envelopes for commercial buildings. The same techniques are being applied to residential buildings with complete success.

The Thermal Envelope can remedy many of the symptoms ailing “sick buildings” in Southern and Northern climates. A necessary step in the “cure is that we must change the environment. “Fix-it” or “Band-Aid” approaches are only a temporary solution putting the problem off to reoccur another day. Generally condensation, duct sweating, infiltration, humidity control and bacteriological growths within building envelopes vanish when eliminated with Structural Insulated Panels.

     The Structural Insulated Panel System is the most comprehensive method to address the remediation of a building envelope. The diverse application techniques and the inherent properties of Structural Insulated Panel allows it to accomplish the most difficult and otherwise impractical sealing and insulating jobs with assured success. The Structural Insulated Panel Thermal Envelope allows the control of humidity levels within the 45-50% range, a level at which molds, mildew, dust mites and many allergens perish, immediately affording the occupants maximum indoor air quality.  The system, also improves the thermal comfort within the entire envelope and vastly improves energy efficiency. The sum of the results is clean, comfortable, healthy, energy efficient, sustainable construction; that will extend the life of the building envelope and the systems with in it.      

    Standard residential and commercial construction has traditionally designed vented Attics without regard for regional and climatic conditions.  Also, many vented attics are not designed and constructed in accordance with properly proportioned eve and ridge Venting. This can accentuate the problem of extreme attic conditions. In warm humid Climates, attic temperatures can reach well in excess of 130 degrees Fahrenheit. This,

coupled with the infiltration of moisture laden air and attic pressurization, can cause a Myriad of problems for energy efficiency, indoor air quality, condensation and comfort. An attic cannot be vented enough to minimize these conditions. The ambient outdoor Conditions would be preferable to the extreme conditions that are created.

   The Thermal Envelope utilizes an un-vented, (sealed) attic design that places the insulation at the roof plane in lieu of on the ceiling, thereby bringing the entire building envelope within the thermal and air barrier.  Research has proven that there are many benefits to this method. By locating the thermal and moisture barriers at the same plane, it eliminates the opportunity for moisture to enter the attic and condense. Moisture will  not condense with in the Structural Insulated Panel (SIP’s) making it the ideal material for this application.

    The Florida Solar Energy Center attributes 65% of the infiltration in the average Florida home to the attic. This coupled with duct leakage can place an insurmountable burden on the mechanical systems to maintain occupant comfort. Many times the results are more drastic leading to failures in buildings and homes. Generally there are many contributing factors: however, the most significant element is the failure of the building envelope. If we first address how we build the “closed box” then we can better engineer the mechanical systems within that “box”.