Moisture Performance Of An All-Wood R-30 Wall

Natural alternatives to foam insulation are highly desirable for high-performing wood-framed buildings.  But lignocellulosic materials can be highly bio-nutritive and moisture absorptive, increasing their vulnerability to degradation and reduced thermal performance.  Designers are often faced with the dilemma of selecting materials that are less environmentally safe for much improved performance.  In this article, I describe a…

Degradation of Fiber Cement Siding

Degradation Of Medium-Density Fiber Cement Siding

Fiber cement cladding has found wide acceptance as a durable and renewable material.   Since entering the U.S. market in the early 1990s, assumptions on its long-term resiliency have relied heavily on wet/dry cycling tests, but little is reported on its durability under typical in-service conditions.   Here we describe four stages of fiber cement degradation under…

Is TimberSIL Resilient?

TimberSIL is a glass-infused wood manufactured by Timber Treatment Technologies.  Marketed as a green substitute to conventional chemically-treated wood, TimberSIL has come under recent scrutiny for questionable performance under intended designed conditions.  We use this situation to discuss the implications of vetting new products on the basis of green material ratings. Criticisms have emerged over the product’s susceptibility to rot and poor acceptance of common coatings.  Perhaps…

Performance Of Decay And Termite-Resistant Wood

In an earlier post, we reviewed standards and implications pertaining to mold-resistant construction materials (December 20, 2013).  We limited our discussion to some of the most widely used resistance tests performed under short-term, laboratory conditions.  Here, we take the discussion further by examining decay resistance tests for treated and untreated wood. Treated wood products provide an essential…

The 2012 Energy Code Necessitates Perfection

Adoption of the 2012 International Energy Code will require exterior continuous wall insulation for climate zones 6, 7, and 8.  When used in combination with cavity insulation, the minimum requirements include 20+5 or 13+10.  The first value pertains to cavity insulation whereas the second is continuous exterior insulation (CI).   Although comparable insulation strategies are also…

Brick And Concrete Masonry Failures: Considerations For Preserving Post-War Era Buildings

Concrete masonry construction was common practice in post-war Modern architecture where it was used extensively in schools, churches, public buildings, and industrial complexes.  Brick and concrete block-bonded construction gained favor in many public buildings for its perceived durability, aesthetics, and relative ease of construction.  Over 50 years later, many of these buildings now have historic significance but suffer…

Mold-Resistant Construction Materials: Godsend Or Gimmick?

Quality moisture management relies heavily on guidance intended to reduce surface relative humidity below thresholds for mold.   The companion to this approach is centered on using materials that are more resistant to mold either by using naturally resistant materials or by employing materials and products manufactured with chemical inhibitors.  Mold-resistance strategies assume that materials can sustain…