Blog Post

Schooled by Peter Yost: An Interview with the Educator of the Year

BuildingGreen’s building science expert shares reflections, hopes, and—as always—practical building advice after receiving two national teaching awards.

September 29, 2015

By Candace Pearson

Peter Yost lives and breathes by the motto “There’s no hygrothermal free lunch” (a phrase borrowed from his friend and mentor Joe Lstiburek). Any student of Peter has that phrase as fundamentally entrenched in their brain as ’I’ before ‘e’ except after ‘c’.

That’s the true mark of a great teacher. But winning awards doesn’t hurt either, and this year, Peter was recognized as Green Building Educator of the Year by the National Association of Home Builders (NAHB) and awarded the Energy Center of Wisconsin’s (now renamed Seventhwave) Educator of the Year Award for 2015.

The awards have been a welcome acknowledgement of work that is sometimes overlooked among the multitude of consulting projects he’s involved with as vice president at BuildingGreen. In any given day, he may easily jump from a hygrothermal building assessment for a homeowner to a commercial documentation review, then to a contract research project for the Environmental Protection Agency or the U.S. Green Building Council (USGBC).

As just one of the many students who has been introduced to the world of building science by Peter (he’s now my boss at BuildingGreen), I sat down with him to learn more about his vision for high-performance building and why he’s made sure teaching remains a part of his daily mix. Always as good-natured as he is insightful, his answers might surprise you.


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A lot of what you teach is about managing moisture as we increase the energy performance of a building. How did this become your focus?

Its ironic, but my graduate work was actually on construction waste management. In fact, that’s how I got to know Alex and Nadav: I had a reputation for being the trash guy. [Alex Wilson is BuildingGreen’s founder; Nadav Malin is its current president.]

I really didn’t know all that much about real building science until 2000, when I first met Joe Lstiburek and Betsy Pettit from the Building Science Corporation. I had learned a lot about buildings while I was at the [NAHB] research center, particularly from Dan Cautley. He taught me about how to really research buildings. But going to work with Joe and Betsy in 2001 was a complete, deep immersion in how buildings work. So I would say [the focus on moisture management] started with Joe and Betsy.

It’s funny, you would think there are some climates where moisture is not the issue—but it’s actually pretty hard to find them. Moisture problems in hot, dry climates tend to come from irrigation systems that are watering buildings instead of watering the plants. So you still have to build buildings in a way that protects them from moisture, even if the climate is dry.

Your students are often inspired by your enthusiasm for how much in building science has yet to be discovered. What do you see as some of the big, unanswered questions that might take us to the next level of green building?

I think we still don’t know how to put buildings together correctly, but taking well-built buildings apart is really challenging. The stuff we use to make them airtight and watertight makes them even more difficult to deconstruct.

That’s a problem because the reusability of salvaged materials is sometimes dependent on how easy it is to take things apart. So I think designing for the disassembly of high-performance buildings is a huge area for research.

For example, in cars we use gaskets as opposed to sealants and sticky tapes because we know if something breaks, we have to get in there and replace the part. We build windows with gaskets, but for most other large structural pieces, they don’t exist, or they are very expensive. We’ve written about design for disassembly, but most building scientists are focused on how to make sticky stuff last longer. Ultimately, that might not be the right question.

For me, this all comes full circle to my construction management days, when we did a lot of work focusing on whether it’s better to take a building apart or to knock it down.

You often do trainings for builders and designers—practitioners who are steeped in challenges presented to them in the field. More recently, you’ve also started teaching in more academic settings. What inspired you to reach out to students at that level, and what have you found to be different?

When I’ve taught at University of Massachusetts–Amherst and Boston Architectural College, the students were mostly budding practitioners. With Yale University, it started a little differently. It can’t really get any more academic than Yale, yet second-year graduate students were coming back to the school and asking for more real-world applications of what they were learning in classes.

I was hired strictly to connect academic learning to practical experience in buildings. In fact, when they hired me, they said, “You do understand that we are not hiring you for your academic qualifications, right?”

What made that work was that it was the students who drove the process. I participate in the Building Science Education network through the U.S. Department of Energy’s Building America program, and what’s fascinating is that it doesn’t matter if we try to target high school students, two-year trade programs, or four-year degree programs: we are always told that there is not enough room in the curriculum for any more material. So here we are preparing people to build buildings and saying that there is not enough space in the curriculum to explain how buildings work.

Even programs that are aware of the need are struggling to find a solution. Making it an elective or a certificate track are two options. Either way, it is so important to continue to make the connections [between academia and practice]. I found that it doesn’t matter if you are working with a high school student or a 35-year veteran; you get a charge out of seeing their “ah-ha” moments.

You’ve been remodeling and examining buildings for 25 years. What is one practice that has changed for the better and one practice that has remained the same or changed for the worse?

There’s no doubt that performance testing is making a huge difference. When builders and architects use blower-door testing to guide air sealing, that is a huge change for the better. When they are building window installation mock-ups and testing them with a spray rack or garden hose for resistance to water penetration, that is a huge change for the better.

But it is really sad how many buildings still aren’t built right. When I was a builder, I had no idea that there were important performance features other than the one lens through which I was looking at the product. If I was looking at plywood or oriented-strand board, I was only thinking about how they compared structurally because they were both “structural sheathing.”

So thinking of products as just one-for-one substitutions—we still do that. And when we have people coming out of four-year architectural schools who have not taken any building science classes at all, building in or spec’ing the wrong product is continually going to be a problem.

One of the most common examples I see is specifying housewrap or building paper as either a weather-resistive barrier or an air barrier and not understanding the difference between the two. The difference between an air barrier and a vapor retarder is so fundamental to the way buildings work, but many people don’t understand how much is packed into that question.

One of the difficulties in our industry is that there will always be a group of people who don’t want to spend three years learning building science just to know what housewrap to spec: they just want to be told what to do.

Then there is always another group who says, “How dare you tell me what to do!” It is really challenging to provide both pathways in either code or guidance. Furthermore, if I do tell you which one to use and you don’t understand the context that led me to make that recommendation, then you are going to put the same product in a different project, and it won’t work. Then you’ll come back to me and bite my head off. So prescription without education is really hard.

I know one of your biggest frustrations has been slow progress with getting appraisers and lenders to recognize the value of green buildings. What needs to change?

When I was first working at research center—and later with Joe and Betsey— I finally really understood how buildings work. And I said, “Now I got it; I’m done.”

But then someone said, “Sure, you know how to design it right and spec it right, but most of the quality depends on how it is built in the field.” Oh, sh**! Does that mean I have to know about quality management? The answer is yes. So you learn a few more things about that.

Then someone said, “Well, you really can’t build high-performance buildings if you can’t sell them.” So does that mean that as a proponent of high-performance buildings I need to understand how to drive the market from the economic side? The answer is yes; we need to understand that too.

Even if you design and spec a building correctly, all of a sudden the homeowner goes to get a mortgage, and the home costs 10% more, but that 10% is not factored into the appraisal—so all the other stuff you’ve done is all for naught because the owner can’t get a mortgage that reflects the higher value of that home. So the financial side of the equation is really important, and the solutions have to extend outside our building industry circles.

We’re making progress in this area, but it has been incredibly slow and spotty. The financial industry turns out to be a lot like the building industry—incredibly risk adverse.

What do you consider to be one of your greatest successes—teaching or otherwise?

Receiving these awards from the Energy Center of Wisconsin and NAHB was really important to me. I do think of myself as a teacher, and it was pretty gratifying to get that type of feedback—especially from two such different organizations. It really says a lot that an association that represents the whole industry is looking for the same quality of information as an organization that’s really progressive in terms of promoting high-performance buildings. I was never asked to change one bit of content.

Another thing that I still feel really happy about is creating the site-engineered environment (SEE) stud, which is a method of piecing together waste scraps of sheathing materials and lumber to create studs for non-load-bearing walls right on the jobsite. The name is a play on the C-studs used in metal framing, which look like a “c.”

With metal, you can select different gauges depending on the strength you need, but with wood, you use the same stud in a structural application as you use for a non-load-bearing wall. It seemed like a huge waste to put a huge structural 2 x 4 in non-load-bearing wall. So to make a SEE-stud, you take 2 x 4 off-cuts and extra strips of OSB, and you engineer a scrap stud. I made that up! It’s never been commercialized, but it’s the thing I’m most proud of.

Learn more about Peter’s work and highly sought courses

Webcast: Healthy Insulation, Buildable Details

On-demand course: Fundamentals of High Performance Building Assemblies

Request Peter’s expertise: Speaker’s Bureau

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