EpiPHany Corner | Do Pass/Fail choices deliver optimum performance?

Even though it seems intuitively obvious that the logical answer is NO, a surprisingly high percentage of decisions regarding the design and construction of new homes are made on a Pass/Fail basis. “Building to code”, means complying with at least the minimum acceptable requirements in the large number of specific areas where compliance is required. Code is a Pass/Fail system and if a building does not meet one or more of those minimum requirements, it fails.

“Quality is more than the absence of defects…”  This anonymous quote is both accurate and applicable to building codes, which are crafted to avoid known defects and/or unacceptably inferior standards and do protect the public from many bad choices. However, they do not incorporate the second part of the quote, “…it is the presence of value.” Avoiding things that are defective or wrong is a good tactic but choosing something above the minimum acceptable in order to gain something of value can also be important.

When homebuyers contract for the design and construction of a custom home, or select a house plan from a developer, they are generally very involved in selecting appliances, furniture, fixtures, finishes and other components or systems that will have an impact on their lifestyles in the home. However, these same homebuyers are often fine with their designers and/or contractors “complying with code” for other elements that, while not visible, can have negative impacts on comfort, health, and sustainability.

An illustrative example:

Codes are evolving toward increased level of airtightness, to improve operational energy efficiency. Homes do not necessarily “need to breathe”, but occupants do, so in order to ensure continuous fresh air for occupants, California code now requires “mechanical ventilation” to bring in that fresh air. A newly constructed home that does not have mechanical ventilation, is not code compliant and fails to pass approvals and inspections.

Unfortunately, the requirement for mechanical ventilation can be met by installing one-or-more bathroom fans that are set to run all the time, continually depressurizing the home. It is true that the bathroom fan approach results in a continuous flow of “replacement air”, but much of that air is being drawn into the home through existing leaks in the envelope. Unfortunately, that replacement air is not necessarily “fresh”, nor is it filtered. A significant portion comes up from the crawlspace through leaks along walls, stairs, and around electrical sockets, down through ceiling lights and other unsealed leaks between the attic and the conditioned space, and through leaks in the heater or AC ducting. This unfiltered air from unknown sources nearly always contains significant amounts of airborne pollutants and allergens. The bathroom fan approach provides replacement air, is code compliant and passes the Pass/Fail scenario, however a balanced mechanical ventilation system provides an equal amount of fresh air (which can be filtered if desired) to continually replace the stale air being expelled and is a much healthier and responsible choice.

Evidence supporting the example:

Most of us have seen light colored carpets with dark areas along the base of the walls or edges of the stairs. This is not because the vacuum does not reach the edges. It is because the carpet is acting as a filter and catching, at least some, of the airborne pollutants and allergens that are being brought in with the air being pulled from the crawlspace. The two photographs below illustrate the problem. Some of the airborne particles get trapped and discolor the carpet along the base of the wall and the edges of the stairs. However, the majority of those particles are suspended in the air that occupants are breathing, and children, whose lungs are more sensitive, are breathing the air from much closer to the floor and stairs.

Homeowners who default to code compliant do benefit from the absence of known defects, but often miss opportunities to enjoy the presence of value related to health, comfort, durability, resilience, and other positive performance attributes. Passing with a grade of D rather than a grade of A or B is definitely not optimum performance.

Author: Jay Gentry