Is the Perfect Wall Realistic?

Posted by Eric Werling on July 01, 2016
Is the Perfect Wall Realistic?

Wrong question. The right question is what can we do to help builders design and construct more perfect walls without losing their shirts? At Building America, we have an idea for a tool to do this.

Since 1995, Building America Program experts have developed more than 100 innovations that help save households across the nation up to $50 billion. One of the most prolific building scientists in the history of the program[1] is Joseph W. Lstiburek[2], Ph. D., P. Eng.[3] of Building Science Corporation. Many folks call him Dr. Joe. He has worked for decades helping builders improve the thermal performance and durability of their buildings. Dr. Joe knows building envelopes[4] – the good, the bad, and the ugly. And he speaks and writes (a lot) about what he calls the “perfect wall system” which elegantly describes the four essential functions of the protective layers outside the building’s structural skeleton. Dr. Joe and his detailed drawings have taught many thousands of building professionals how to effectively control water, air, vapor, and heat flow through building assemblies.

But, even Dr. Joe would admit that his “perfect wall system” is only perfect IF its principles are correctly adapted to the building type and climate zone, and WHEN it is installed correctly with the right material choices. These IFs and WHENs are not easy. If done right, moisture-managed high-R walls deliver durable, zero energy ready levels of performance with little to no risk of building failures. If done wrong, extra insulation and vapor barriers in the wrong place can cause all sorts of nasty moisture problems. This is why it’s so hard for builders to try innovative envelope solutions. This fear of doing it wrong. There are countless complex decisions involved in specifying and constructing building envelope systems today. Without expert knowledge guiding the design and construction of any new high-R wall systems, they can be risky and/or expensive business for builders. Risky business means fewer builders using innovations to improve envelope performance.

This is the essence of the challenge we’ve taken on with the Building America High Performance Moisture Managed Envelope Solutions Roadmap, described in the Building America Research-to-Market Plan. To meet our aggressive long-term program goals of enabling massive adoption of zero energy ready homes, we need to help the construction industry to specify and build more “perfect” envelope systems - easily and cost-effectively. To do that, we will need to help remove the technical and business risks of adopting new, high performance envelope systems.

And since there aren’t enough building science experts to go around, we will also need to find better ways to make that expert advice more accessible. We need more than just guidance documents for that. Among other things, we need tools that building professionals can use to efficiently learn and access building science knowledge and expert advice.

We have already built one such expert tool. The Building America Solution Center was launched back in 2012, and it keeps getting better. Today, the solution center is visited more than 40,000 times a month. And we’ve added some great new features lately, including advanced search filters that help zero in on building science expertise from over ten world-class research teams and four national laboratories. If you haven’t been to the solution center lately, you’re missing out.

But every builder knows you need the right tool for the task, and it takes a lot of tools to build a house. The solution center is a great tool to help you implement best practices once you have decided which ones to implement. But the solution center is not designed to help you make the complex decisions about which high performance wall design is right for your application. Which envelope solutions will deliver the best value to your customers with the least risk to your business? Today, to help you with these tough decisions, we have a stack of guidance documents and a handful of experts like Dr. Joe who don’t have enough time to teach and advise every builder in the country.

Wouldn’t it be cool if we could put all of the best building science expert wisdom in a user-friendly design tool that helps you with those complex decisions? Well, we have just begun an effort to do just that. Last week, we met with scientists from the Oak Ridge National Laboratory and some of the world’s top experts on durable high performance wall system design to begin developing an online “expert system” tool that can help builders through moisture-managed high performance envelope design decisions. The tool will draw from Building America research projects, lab and field test measurements of high performance wall systems, computer aided risk analysis, and the expert judgement needed to make sense out of all the data.

Users will be prompted to enter relevant information about the building location, design, and material selection options. Influential factors such as climate, building air tightness, material properties, and internal moisture loads (people) will be taken into consideration to estimate and compare the moisture durability performance of several design options at once. Users will be able to more confidently select the assembly design characteristics that achieve their design goals with the least risk. Links to design-specific guidance will also be provided to help users manage any remaining risks.

We believe that helping builders to truly understand risks, simplifying complicated decision-making processes, and validating cost competitive solutions, will help them make better decisions and move the industry forward to the next generation of high performance zero energy ready homes. We hope this new tool concept will be a big step toward achieving this goal.

If you want to be on the list of beta testers or if you want to share ideas about research needs that you think Building America needs to tackle, tell me about it. My email door is always open.


Eric Werling is a Building America Program Coordinator for the Energy Department's Building Technologies Office. 

[1] As of today, there are 36 Lstiburek documents listed in the Building America Solution Center, more than any other author – by a lot. Second place is “EPA” which isn’t really a person, and third is “BSC”, short for Building Science Corporation. We should probably fix that.
[2] “It’s pronounced Stē – brĭk” (direct quote from one of Dr. Lstiburek’s t-shirts).
[3] Canadian for PE, which is American for Professional Engineer.
[4] He says Enclosure, we say Envelope. Same thing.

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