You can get yourself in a lot of trouble in our industry by
thinking you know what you really don't. From the business end,
that's always been true; "knowing" that you should mark up 10
percent for overhead and 10 percent for profit, for instance,
or "knowing" that the billing rate in your area for a skilled
carpenter is $45 an hour — regardless of what your own
numbers tell you — is the kind of pseudo-knowledge that
can get you into a deep hole pretty quickly.
That particular form of ignorance masquerading as knowledge,
though, is self-correcting; the financial feedback loop tells
you in fairly short order to either change your ways or exit
Another type of pseudo-knowledge has a longer and more perilous
feedback loop, and that's "knowledge" of basic building science
— thinking, without basis, that we understand the rules
of physics, chemistry, and biology as applied to the work we
A World of Misinformation
Let's be honest here: Not many of us are in construction
because we were such standouts in science class. So we're
vulnerable to misinformation based on industry habit, stubborn
myths, and outright fraud — not on sound empirical
science. There's a lot of unreliable information out there, and
our industry seems to have more than its share. The advent of
the Internet has given us all unprecedented and instantaneous
access to an ever-expanding reservoir of lousy advice.
For instance, more and more homeowners are becoming sensitized
to mold and other air-quality issues, viewing them as potential
household hazards. Combine this fear with widespread ignorance
and the occasional large insurance-company payout and you have
a potential liability that's hard to know how to manage. That
people who think they're being poisoned by mold tend to believe
whoever is giving them the most alarming information further
exacerbates the problem.
In such situations, you'd better really know what you're
talking about rather than just think you know —
especially if you've broken a pipe and caused some minor
flooding, as we did on a recent project (1/2-inch pipe, 60
seconds of flow).
It was my word against that of the mold guy, who wanted us to
tear everything out because that was his one-size-fits-all,
cover-your-rear approach to any situation that involved a leak.
I was lucky, because I had access to better information than he
did, but it still took a lot of time and effort to convince the
homeowner that a total tear-out was going to be a waste of time
and an unwarranted setback in completing the project.
Let's be honest: Not many of us are in construction
because we were such standouts in science class.
Beware the Sales Pitch
It's not just clients who can cause problems based on faulty
building science. A chronic problem within our industry has
been deceptive claims from radiant-barrier sales
representatives. I recently wasted several hours dealing with
subcontractors, staff, suppliers, and Web sites advocating for
the use of a 1/2-inch-thick radiant blanket as insulation under
a concrete slab with radiant heat.
The claim — totally bought into by the smart, experienced
people I was working with — was that putting the radiant
blanket under the slab would give us an R-value of somewhere
between 5 and 10 (depending on who was doing the talking). This
is complete nonsense — actual performance from such a
product in a subslab installation might be roughly equivalent
to R-1 at best.
In addition to its poor thermal performance, the product was
going to cost more than 1-inch extruded polystyrene, which has
an R-value of about 5. So the accepted industry "wisdom" was
pushing for the use of a product that cost more and performed
worse than readily available alternatives.
Those anecdotes, chosen from among many, illustrate how
important it is that as professionals we be as well and as
reliably informed about basic building science as possible. The
corollary to this, of course, is that it's a major liability
not to be well-informed.
Over the years, through trial and error, wide-ranging reading
and research, and ongoing conversations with a spectrum of
leading building scientists and practitioners, I've gotten a
good idea of where I can find trustworthy information and
Here, then, are resources for building-science information that
I've learned over time I can rely on.
Trust Your Own Observations
What you can see with your own eyes — rot, mold, water
trickling down a basement wall — is unassailable. It
constitutes the most reliable information you've got about
building performance problems.
What may be less reliable is how you interpret that
information. It's a big leap from "I see mold" to "This mold
was caused by the previous contractor's poor flashing details."
There can be a lot of steps from the initial observation to the
ultimate conclusion, and each one represents an opportunity to
Make your observations, ask questions, and take short steps
rather than giant leaps when it's time to start drawing
Multiple observations over time are more reliable than one
observation at a single point. That's why it's so essential to
have an organized strategy of periodic returns to past jobs if
you're serious about understanding building performance with
regard to your own projects. Take pictures and good notes and
store them in an accessible location.
At my company, I have assigned one person the task of "warranty
manager" so that we have a single, consistent source for
performance data for all our projects. He gives periodic
reports at our company meetings to let us know what's working
and what isn't; this allows us to deal with problems head-on
and solve them once instead of over and over and over.
Use Your Ignorance
This may seem like an odd sort of "resource," but I assure you
that you'll get into less trouble by assuming you don't know
what's causing a problem than by assuming you do. In other
words, don't be afraid, at first, to say to a client "I don't
know" — even if you think you do.
Formulating an initial hypothesis is okay, but jumping to a
conclusion is not. There's a subtle but important distinction:
Whereas a hypothesis suggests that more testing or
investigation is called for, a conclusion implies that you're
ready to fix the problem whether or not you've really
identified it. Even if it's a problem you've seen before, it's
worth stepping back a moment and asking yourself if the root
cause could be something new.
Cautionary tale No. 1. Twenty years ago, I built an addition
off a kitchen with a cathedral ceiling that contained some
problematic lights: After snow fell, water would drip out of
them. Obviously, the problem was a roof leak caused by an ice
dam, right? An open-and-shut case.
So we stripped the roof, put down bituthene — all the way
up, instead of just at the eaves — and reroofed.
Next time it snowed, the lights leaked again. Time for a closer
What was happening, it turned out, was that warm, moist air
from the kitchen was leaking up around the recessed lights,
condensing on the underside of the sheathing, and freezing.
When snow fell, it would act as a layer of insulation on top of
the sheathing, allowing the recessed lights to heat up the
rafter cavity and melt the ice (the frozen condensation), which
dripped down through the light.
Cautionary tale No. 2. About 10 years ago, we had a problem
with chronic paint failure on clapboards — from day one,
they couldn't hold a coat of paint.
The painter said it was indoor humidity migrating through the
wall and taking the paint off with it.
The paint manufacturer's rep said it was "mill glaze," meaning
the surface was too smooth to hold the paint and we should have
scuffed it up by lightly sanding before painting.
The lumber-mill rep said the painter shouldn't have used latex
primer, that oil primer would have "soaked into the wood" and
They all thought they knew exactly what was going on, and all
were clear that it was someone else's fault. Yet nobody was
Further tests and investigation revealed the culprit: surface
water wicking up between the clapboard joints and soaking the
back of the clapboards, which had not been back-primed prior to
installation. The wetting from behind made it very difficult
for paint to stick over time.
Luckily, we solved the problem relatively inexpensively by
inserting plastic wedges at every nail to create a space
between the clapboards too wide to allow for capillarity.
Don't Forget to Read
Here's a list of the books, magazines, Web sites, and other
resources that, in my experience, will do the best job of
keeping you out of trouble.
Energy Design Update. This periodical is pricey ($385 for 12
issues a year at 16 pages each), but it's the most important
one I receive in terms of understanding residential building
science and keeping up with the latest research. Any
publication that can irritate members of the radiant-barrier
industry and preeminent building scientist Joe Lstiburek at the
same time — while retaining them all as subscribers
— is doing something right.
Editor Martin Holladay is also extraordinarily generous with
his time and expertise on a number of energy-related online
forums; he's a voice of reason, providing an antidote to much
of the unreliable information out there.
Joe Lstiburek's Builder's Guides (Building Science Press).
These climate-specific handbooks of good construction details
are invaluable. Their focus is on new construction, so they're
less helpful in retrofit situations. (Ever try to add proper
flashing details to a brick wall after the fact?) Still, the
building science behind the recommended details is rock solid,
and the illustrations are models of clarity.
Building Science Corp.'s Web site. The principals and staff at
Building Science Corp.
(www.buildingscience.com) have put together
an extremely useful online resource for a broad range of
residential building-science issues. Log on to the site and
start trolling — there's good information, accessibly
presented, everywhere you turn.
Water in Buildings, by William B. Rose (Wiley, 2005). This book
may be heavy going, but it is the closest we have (and probably
will have for years to come) to a definitive study of the
topic. The content is as honest and objective as it gets in our
industry — no axes to grind, just the facts. Keep it on a
nearby shelf as a ready reference.
Camroden Associates' Web site. This is the Web site of Terry
Brennan, principal of Camroden Associates
(www.camroden.com). Terry's work on mold in
buildings is solidly positioned where theory meets practice. I
hired him to give a talk on mold at one of our company meetings
and his dirt-under-the-fingernails approach earned real
credibility with my field crew (and not just because he
blatantly contradicted several things I had been telling them,
as enjoyable as that was). The papers you can download from
this site — coupled with mold papers you can download at
Building Science Corp.'s site — will give you a really
solid understanding of the issue.
Understanding Ventilation, by John Bower (The Healthy House
Institute, 1995). Dated, with some inaccuracies, this is
nevertheless a very useful resource. I keep it next to my
Builder's Guide to Cold Climates and Water in Buildings. Given
the topic, it's surprisingly readable. The book is now out of
print, so you'll have to find a secondhand copy.
Environmental Building News. Green building is becoming less a
political than a business statement: It's increasingly
difficult to make useful distinctions between green
construction and quality construction. Alex Wilson and Nadav
Malin have done an outstanding job keeping EBN the premier
publication on green building. EBN is not a cheerleader for the
green-building movement — it covers the failures and
problems as frankly and reliably as the successes.
JLC Live, Building Energy, Affordable Comfort, and EEBA's
annual conference. These four shows all provide essential
opportunities to hear firsthand what's going on in the world of
residential building science, and to ask questions and compare
notes with others struggling with the same problems.
It goes without saying that these resources, helpful as they
can be individually, are even more useful collectively.
Effective risk management starts with good information, and in
our industry getting good information can be a challenge. These
resources should make meeting that challenge a little
Paul Eldrenkamp owns Byggmeister Inc., a
custom remodeling firm in Newton, Mass.