Historic Structures Deserve VIP Treatment

Restoration of historic buildings is tricky business. Among other challenges, preservation concerns severely limit façade alterations.

Restoration often includes deep energy retrofits which generally increase the thermal resistance (R-value) of the envelope. For existing structures adding insulation to the exterior is generally preferred over the interior as adding insulation from the inside will reduce its floor area. But for historic structures this approach is self-defeating.

Vacuum insulation has been used widely in non-building applications like refrigerators, thermos containers, and thermal doors. Its use in building envelope insulation is fairly new and still in R&D.  Vacuum Insulated Panels (VIPs) are composed of two stainless steel plates which sandwich a core of vacuum and fumed silica.

VIPs  possess 5-10 times the R-value of conventional insulation. Hence the thickness of wall sections may be far less than conventional insulation, effectively increasing the floor area. The resulting space savings alone are estimated to be $152 per foot of wall assuming a value of $182 per square foot of space.

Moreover, it has also been proven that the VIPs can add to the structural strength of the wall which then reduces the material necessary for structural members.

VIPs however are not perfect. Their stainless steel edges conduct heat, thereby reducing efficiency–though this has been largely mitigated by replacing its straight edges with serpentine ones. Other problems arise out of the panels’ fragility, allowing gases to enter its core and potentially rendering them useless. Gases will ultimately penetrate the VIP which limits their lifespan to less than 40 years.

VIP installations remain elusive owing to their high cost and a lack of proven history. Researchers believe these issues will be eliminated with enhanced technology and that VIPs will play a far more significant role in the future.

VOCs paint an ugly picture

Who doesn’t love the smell of fresh paint?  But, as so often seems the case, the good things in life are bad for us.

Green buildings transcend their structure and actually produce a positive effect on the health and comfort of their occupants. A key factor which determines this is the type of architectural coatings (paints, sealers etc.) and how many volatile organic compounds (VOCs) they contain.   Alas, these toxins are responsible for that wonderful fresh paint aroma.

VOCs are mainly used as solvents in coatings and contain aliphatic hydrocarbons, ethyl acetate, glycol ethers, acetone and formaldehyde.  In addition to being virtually unspellable, all of these have a very low boiling point slowly evaporate at room temperatures to be absorbed in to the human body. (Formaldehyde has a boiling point of -2F!) Low VOC coatings, by contrast, are those which contain water-based solvents.

Some of the harmful effects these VOC’s include irritation, headaches, loss of coordination, nausea, damage to liver, kidney, and central nervous system. Some are even suspected to cause cancer.

The EPA estimates that in a typical building the concentration of VOCs could be up to 5 times the concentration of outdoor air. In fresh paint this can be about 1000 times. In a society which spends most of our time indoors, the use of low VOC coatings can go a long way to reduce long term health risks and ensure comfort.