Home Innovation Insights

Ed Hudson, MBA
October 25, 2012

Building Product Market Opps: Attics & Crawlspaces

What's the state of building science in the residential construction industry today? With two decades of marketing research among home builders under my belt, I can say with certainty that building science principles are far better and more widely understood than ever before, and that home builders' vocabularies are brimming with building science terminology. That being said, there is often little agreement, and sometimes outright confusion, on how to apply building science principles and which of the many new solutions is best for a given scenario.

The ability to predict industry reactions to the evolving doctrines of building science can be a source of opportunity for building products manufacturers and service providers. Aside from having “first mover” advantage as you position yourself to benefit from building trends, you are also in the best position to develop new solutions to home building challenges when on the forefront of these evolutions.

Recently, for example, we've seen a change in thinking on moisture and thermal dynamics. More doubts are creeping into builders' minds on the long-accepted “necessity” of attic and crawlspace ventilation, which has been enshrined in our home building heritage and in the pages of our building code books and product warranties. Proponents of unvented attics recommend placing insulation on the underside of roof sheathing instead of on an attic floor, which keeps the attic space conditioned and allows HVAC ductwork in the attic to remain within the building envelope for greater occupant comfort and energy efficiency. And an unvented crawlspace foundation requires adding insulation to crawlspace walls to create a conditioned space for air ducts and air handling units for improved energy efficiency, and fewer problems with crawlspace moisture. 

To help track where this change in the industry's collective thinking is headed and get a read on the popularity of unvented attics, crawlspaces, and insulation types, Home Innovation Labs conducted a nationwide survey of builders earlier this month. The study showed that about 17 percent of U.S. home builders specify unvented, insulated attics (excluding attics used as living space). We found unvented attics are most popular in the South, accounting for 23 percent of new homes there — undoubtedly due to the hot climate and the common practice of placing HVAC ducts in attic space. Unvented attics are least poplar in the Northeast and West with about 10 percent share. The most popular insulation used with unvented attics is spray foam — about 74 percent of builders reported using it with a full cavity fill or in combination with fiberglass batt. This was followed by fiberglass batt-only insulation at 20 percent, and rigid foam at 6 percent.


(Source: Home Innovation Research Labs Annual Builder Practices Survey)

While we don't gather information on crawlspace ventilation specifically in our Annual Builder Practices Survey, we have seen a distinct trend over the last several years that insulated crawlspace walls are gaining popularity, as shown in the graph above. The recent survey further confirmed this belief — unvented, insulated crawlspace foundations were reportedly used by 46 percent of builders who build homes with crawlspace foundations. Unvented crawlspaces are an especially popular choice for homes in the Midwest, accounting for about 70 percent, and much less popular in the rest of the country at about 40 percent.

What's the upside of this information for building product manufacturers? There is still ample opportunity to improve insulation solutions for unvented crawlspace foundations that are fire resistant, suitable for ground contact, and can be installed quickly and cost-effectively with minimal chance of error. For unvented attics, new solutions can speed the adoption of this practice as long as they keep it cost effective, minimize disruptions to home design and construction processes, and include options compatible with popular structural materials (like trusses and OSB sheathing). And don’t forget about opportunities to improve all the existing homes built during the decades before we became more "enlightened" in our thinking on vented attics and crawlspaces.

Assessing the early momentum of change in building practices can provide clues to its eventual direction. Let me know if we can help you in this type of assessment for your specific product market.

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Kendall Shive, Insulform-ICF
Wednesday, July 23, 2014 6:39 PM
"I designed and manufacture the most energy-efficient ICF on the market. After 30+ years in commercial/residential construction, I recently completed my first home with an unvented attic. Building in the central Texas area (Austin,TX), Dealing with high humidity is a given. I used R-30 Roxul batt insulation under a radiant barrier and a dark brown (not my choice) metal roof. Although the attic temperature in the dead of summer is in the mid-90 deg range, the humidity in the conditioned space is well above what I expected.
I am an avid proponent of investigating new technologies, therefore I regularly refer to your web-site. I am the last one to jump on the "band wagon".
I have been perfecting my version of the "super-insulated" green home for 30 years. This question of vented or unvented attics has me stumped.
I was disappointed this article does not contain any informational data supporting one method over the other. I have been aware of the unvented attic for years. In an effort to build my customers the most comfortable, cost-efficient home I would appreciate any info you might have access to."