GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Audio Play Icon Headphones Icon Plus Icon Minus Icon Check Icon Print Icon Picture icon Single Arrow Icon Double Arrow Icon Hamburger Icon TV Icon Close Icon Sorted Hamburger/Search Icon
Musings of an Energy Nerd

Ten Questions for Joe Lstiburek

I recently got a chance to interview one of the country's leading building scientists

Dr. Joseph Lstiburek is a principal at Building Science Corporation in Westford, Massachusetts. [Photo courtesy of Building Science Corp.]

Even back in 1999, when I was an unknown editor at the Journal of Light Construction, Joseph Lstiburek, a principal at the Building Science Corporation in Massachusetts, graciously answered my questions about heat flow, air flow, moisture movement, and building materials. Since those early years, I’ve interviewed Lstiburek dozens of times, and he’s never failed to enlighten me (and sometimes, surprise me).

Lstiburek’s answers to ten recent questions are presented below.

(1) Compared to 40 years ago, are residential builders in the U.S. doing a better job?

A. Yes and no. They have a much better understanding of how things work, but the skill set of people doing the work is not as good as it was. The business grew faster than the available school of skilled talent. We used to have apprenticeships, and people had time to learn fundamental skills. That’s not happening anymore. The builders are aware of that, but there is no easy answer that I can see. But builders have a better understanding of how things work—things like indoor air quality, combustion safety, water management, thermal management, and comfort. All of this is much better understood by the day-to-day builder than 40 years ago. I used to be a builder, and—I can’t believe I’m saying this about the 1970s—back then we were skilled at our skill sets. But we didn’t know how things worked. Today’s builder is very sophisticated in terms of financial management, scheduling, and how things work. The problem is delivering. We don’t have the skills to do it.

(2) What aspects of residential building in the U.S. are still frustratingly sloppy or wrong?

A. I’m very disappointed with mechanical systems—heating, cooling, and ventilation. We have insanely good pieces—we have good equipment. What we can…

GBA Prime

This article is only available to GBA Prime Members

Sign up for a free trial and get instant access to this article as well as GBA’s complete library of premium articles and construction details.

Start Free Trial


  1. Expert Member
    Malcolm Taylor | | #1

    Joe speaks sense. Too bad he's a Leafs fan though.

  2. William Hill | | #2

    Oh wow, two of my favorite Building Scientists/writers in one place! What a fantastic gift for the New Year! Thank you so much, Martin Holladay and Dr. Joe.

    The only thing I would disagree with is Martin referring to himself as "... an unknown editor at the Journal of Light Construction." Yeah, OK, but before that you were the first person I would go to for new information, opening up every issue of Energy Design Update with great anticipation.

    Please don't underestimate the impact you have had on the understanding of Building Science in this country, Martin. Yeah, Dr. Joe had an impact, but ya' know he's a Canadian. It took you, Martin, to make it possible for the gospel according to Joe to be spread in the USA.

    All the best to both of you!

    Bill Hill

  3. John Prospect | | #3

    Thanks to both Martin and Joe for a great interview. Always fun to read Joe's thoughts (on pretty much anything).

  4. qofmiwok | | #4

    Interesting that Joe says "as good of windows as you can afford, and more continuous insulation" because in other interviews he seems to support the "pretty good house" idea and being economically reasonable instead of taking things to the extreme. In CZ 6B I'm planning 2" exterior insulation over 2x6 walls, and R6-7 windows. I wonder if he'd think I should do 3" and R8. 4" and R9? 5" and R10? If I can afford it, what's the limit? (And let's face it, anyone building a custom house "can" afford it if it is the priority.)

    1. User avater GBA Editor
      Martin Holladay | | #5

      Joe Lstiburek expressed his personal regret that he didn't include more exterior rigid foam on the walls when he remodeled his house. He could have afforded thicker foam, and he regrets his decision to choose thinner foam -- due in part to the fact that Joe Lstiburek is obsessed with home performance. Only you can decide whether you fall into that category.

      For more information on this topic, see "How Much Insulation Is Too Much?"

      1. qofmiwok | | #6

        Thanks for the link. But it really was focused on energy savings as opposed to comfort and building sciences issues like condensation and mold. My guess, after reading / watching Joe quite a bit, is that he isn't basing his responses on cost/benefit payback but on these other issues. it would be interesting to know for sure.

  5. Derek Maxwell | | #7

    Yes and No. As a young builder who got a late start I am here to learn and I am so grateful for the resources here and that Dr. Joe has published with BSC. It’s true, jobs are complicated but nobody seems to know what they are doing in a big picture sense. I also agree with Mechanical being one of the weakest links, like Lstiburek mentioned we aren’t training people as well as we need to and mechanical systems are only getting more complex.
    I live in Minnesota and I am currently working on a job with 2” of exterior insulation and no one who is on the job has ever done or barely even seen exterior insulation. That is really concerning to me, I mean it gets cold here and then it gets hot, seems like insulation would be a good idea.

  6. Doug White | | #8

    Thsi is why prefabbed walls and ceilings are the way to go

    As for the basement dictum, that assumes you have a large flat lot. While a good basement is hard/not cheap to build dry and warm, it really facilitates HVAC ducts . Wiring, etc. not to mention incalculable value for sequestering noisy teenagers and ones shop. And if you cant do a slab, do a full basement rather than crawl space-they are a disaster in multiple ways. THink of a basement a crawl space you cna stand up in, insulate and seal well, and a Cost effective unless you have low water table etc

Log in or become a member to post a comment.



Recent Questions and Replies

  • |
  • |
  • |
  • |