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Building Science Insights
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Building Science Insights are short, informal discussions that highlight one or more building science principles. Like all BSC publications, they are grounded by solid research and experience. Unlike most BSC publications, however, they may also feature anecdotes, opinions, and even a joke or two (or three…).
Lively and engaging, Insights provide a fresh perspective on important industry issues. Enjoy them with your morning coffee or any time you need to wake up your building science brain.
An edited version of this Insight first appeared in the ASHRAE Journal. The perfect wall is an environmental separator—it has to keep the outside out and the inside in. In order to do this the wall assembly has to control rain, air, vapor and heat.
An edited version of this Insight first appeared in the ASHRAE Journal. Buildings today are hollow and multi-layered with numerous air gaps or void spaces. Chases, shafts, soffits and drops abound. Everything is connected to everything else, typically unintentionally.
An edited version of this Insight first appeared in the ASHRAE Journal. Perhaps it was the drug culture of the 60’s that turned brains into coleslaw but it is hard to understand the lunatic practice of placing a layer of sand over the top of a plastic ground cover under a concrete slab in California.
An edited version of this Insight first appeared in the ASHRAE Journal. Ever wonder how we can build a 50 story glass tower that doesn’t leak, but we can’t seem to build a two-story house that doesn’t leak? The answer is a little bit of counter intuitive thinking.
An edited version of this Insight first appeared in the ASHRAE Journal. Thermal Bridges—steel studs, structural frames, relieving angles and balconies.
When I see a fully glazed, floor-to-ceiling commercial or institutional building, I see an energy-consuming nightmare of a building that requires lots of heating and cooling at the perimeter just to maintain comfort. The result, on a cold winter day, is that offices exposed to the sun require cooling, while those in the shade need heat.
An edited version of this Insight first appeared in the ASHRAE Journal. Many “green” buildings don’t save energy. Why? They have too much glass, they are over-ventilated, they are leaky to air, they are fraught with thermal bridges and they rely on gimmicks and fads rather than physics.
An edited version of this article was first published in the ASHRAE Journal.
I have loved bourbon for a long time. I like the history. And I like the independent spirit of the folks who make it, their sense of tradition, and their willingness to continue to experiment. Even now after two hundred years of history, they experiment mostly by trial and error rather than by computer simulations. I have often thought that if engineers were in the liquor business, bourbon would be the liquor they would make.
An edited version of this Insight first appeared in the ASHRAE Journal.
Think of the good old days—the Civil War, WWI, the Great Depression, WWII—crawlspaces were uninsulated. They were ventilated and they didn’t have ground covers—and they didn’t have problems. Why?
An edited version of this article was first published in the ASHRAE Journal. In this Building Science Insight, Joseph Lstiburek discusses fundamental building physics applied to wine cellars and the storage of wine.
An edited version of this Insight first appeared in the ASHRAE Journal. Water causes enough trouble by itself, but when we add salt we go to a whole different level, especially where porous materials are concerned. What is the deal with porous materials? Simple, porous materials are capable of wicking water large distances due to capillary suction. And when water can move large distances only bad things can happen.
This article was first published in "Perspectives," Volume 17, Number 1. Spring 2009. The on-going consumption of energy to operate, condition, and light a building, as well as the energy embodied in on-going maintenance is the largest single source of environmental damage and resource consumption due to buildings. Reducing the operational energy use and increasing durability should be the prime concerns of architects who wish to design and building “green” buildings.
An edited version of this Insight first appeared in the ASHRAE Journal. So what do you do when you have an old building and the walls aren't doing their job? What do you do when the walls look bad, leak and are falling apart? You give them a face-lift.
The future is uncertain. This is a truism, and yet, when we design and construct a new building, we need to make decisions in the present or very near future. In fact, this is one of the critical distinctions about designing buildings: they are expected and likely to last 50 to 100 years, but we build them now. The challenge of designing for the future is no more acute than in the current choices facing the designer of an environmentally friendly building.
This Insight is an excerpt from Armin Rudd's "Ventilation Guide." This publication can be ordered online from www.buildingsciencepress.com. Experience is a great teacher, but much bad experience can be avoided through education. That is the goal of this Insight. Following some basic, uncomplicated design guidelines can go a long way to avoiding most trouble spots.
An edited version of this Insight first appeared in the ASHRAE Journal. Whenever there is a complaint about air quality in a building the first thing folks want to do is test the air. That is absolutely the worst thing to do. You do not start with air testing. I blame Star Trek. We grew up watching Spock go into a shuttle bay, do a tricorder scan and figure out that a tachyon field was causing the dilithium crystals to break down and that’s why Uhura had a headache. In Star Trek you could measure everything and anything. That’s not the way the real world works.
An edited version of this Insight first appeared in the ASHRAE Journal. You have got to love salesmen. They figure things out way before physicists, usually before engineers and certainly before greenie weenies. They found, what we should all know, that it is much more cost effective to fix the enclosure so that the actual system that you need is small and therefore does not cost much to install and does not cost much to operate. Oh, by the way, this approach also saves energy. Who knew?
An edited version of this Insight first appeared in the ASHRAE Journal. Over the years the big white Superdome roof that dominated the skyline of New Orleans apparently proved to be an irresistible target for folks with weapons. Hundreds of bullet holes were found when the roof of the Superdome was replaced after Hurricane Katrina.
An edited version of this Insight first appeared in the ASHRAE Journal. Energy security is pretty easy to get a handle on—don’t buy oil from the Middle East, Russia, Nigeria and Venezuela. The problem is that it is not cheap energy and it is not clean energy. We can make it clean, and we will, but it will be even more expensive. And actually that is good because we won’t waste it when it is expensive.
An edited version of this Insight first appeared in the ASHRAE Journal. Sometimes things are so obvious we miss them. The Second Law of Thermodynamics is like that. Most of us get the heat goes from warm to cold thing. It’s the other simple applications of the Second Law that we miss.
All space-conditioning systems are intended to provide a comfortable and healthy indoor environment. But the fact is, the the most popular residential furnace/AC systems and commercial VAV systems are fundamentally flawed from their conception.
An edited version of this Insight first appeared in the ASHRAE Journal. If someone invented wood today it would never be approved as a building material.
An edited version of this Insight first appeared in the ASHRAE Journal. What we call things tells us a great deal about how much we understand things.
This Insight reviews the Passivhaus (PH) low-energy house standard and briefly compares it to other cold climate low energy house standards, such as the Building America program, Energy Star, and R2000 homes.
This Insight is in response to questions from clients and interested members of the public and academia, I have recently written about some aspects of the German PassivHaus housing standard as it applies to cold climates.
An edited version of this Insight first appeared in the ASHRAE Journal. Mold is pretty easy to understand. No water no mold. Any questions? Well, there are a few. For one we have more mold today, but we don’t have more water. What’s with that?
An edited version of this Insight first appeared in the ASHRAE Journal. Higher levels of thermal resistance and reduced heat gain across building enclosures has forever changed the performance of buildings—and not necessarily in a good way.
An edited version of this Insight first appeared in the ASHRAE Journal. Stucco was once viewed as a cladding system that solved moisture problems—it is now viewed as one that causes moisture problems. What happened?
An edited version of this Insight first appeared in the ASHRAE Journal. The current industry standard wall is being replaced by a 2x6 frame at 24-inch centers with single top plates, two stud corners, no jack studs, no cripples and single headers (and in many cases no headers at all).
An edited version of this Insight first appeared in the ASHRAE Journal. North of the Arctic Circle there are only two seasons—this winter and last winter. Who would ever want to live there?
An edited version of this Insight first appeared in the ASHRAE Journal. Two of the hottest places in the world, where no one with any sense should build, are Dubai in the United Arab Emirates and Las Vegas in the United States. Who would ever have thought that Dubai could learn from Vegas?
An edited version of this Insight first appeared in the ASHRAE Journal. Wood frame walls are pretty impressive technological creations. How come they look the way that they do? How will they look in the future?
An edited version of this Insight first appeared in the ASHRAE Journal. In a strange world with strange connections one of the strangest connections of all exists among Jan Laverty Jones, John Rushworth Jellicoe, British Dreadnoughts, German U-Boats and Svante Arrhenius.
An edited version of this Insight first appeared in the ASHRAE Journal. Those of us who are no longer young remember how easy it was going to be to save energy by caulking and insulating.
An edited version of this Insight first appeared in the ASHRAE Journal. You build things that seem like they are obviously going to work and then the real world intrudes and reminds you that you are not as smart as you think.
An edited version of this Insight first appeared in the ASHRAE Journal. Spain gave Florida to the United States in exchange for the United States giving up any claims on Texas. Nobody really wanted to live there except the Seminoles until air-conditioning was invented.
An edited version of this Insight first appeared in the ASHRAE Journal. Sheathing does more than deal with wind. Sometimes it doesn’t even deal with that. It wasn’t always that way.
An edited version of this Insight first appeared in the ASHRAE Journal. Five fundamental changes to building construction have occurred in the last 50 years – they happened so gradually, so insidiously that we missed their enormous significance.
A concise history of the improvements to traditional buildings through design and materials.
An edited version of this Insight first appeared in the ASHRAE Journal. I do not have a problem with dense packing walls. In fact, dense packing walls typically results in remarkable performance. It is the dense packing of unvented cathedral ceilings or unvented flat roofs that is the problem.
An edited version of this Insight first appeared in the ASHRAE Journal. Hospitals are not fun places to work in, and they are not fun places to build and design or to fix and repair. The stakes are often high. Nothing is more sobering than when someone dies because of a mistake, especially when the mistake does not seem to be a big deal.
An edited version of this Insight first appeared in the ASHRAE Journal. “When you insulate your basement on the inside, the rubble foundation will freeze apart, and you will get swelling from the freezing soil collapsing the wall, and adfreezing will lift the wall so high you will need a ladder to get down from the sump pit.”
An edited version of this Insight first appeared in the ASHRAE Journal. One of the more difficult questions regarding enclosures is can we insulate the interior of a mass wall in a cold climate without causing damage from freeze/thaw cycles? The answer is usually yes, we can insulate. But, and there is almost always a “but,” it depends.
An edited version of this Insight first appeared in the ASHRAE Journal. Spray polyurethane foam (SPF), the high-density stuff, is the only product (so far) that can perform all of the functions of the principal control layers of the “Perfect Wall.” The functions are water control, air control, vapor control, and thermal control.
An edited version of this Insight first appeared in the ASHRAE Journal. Imagine a three-dimensional molecular billiard game with billiard balls that are sometimes sticky, and where the rules depend on where you are on the table. Then assume that there are many different types of tables and pockets of different sizes.
An edited version of this Insight first appeared in the ASHRAE Journal. Historically, so many problems have occurred with parapets that we have a name for it: “parapetitus.” They have a long history—which of course is not always clear—that allows me to embellish without threat of peer review reversal. Their major function today, aside from confus¬ing architects, is to protect the edge of roof assemblies from wind uplift forces. Not so in the old days where they were useful in fire protection.
An edited version of this Insight first appeared in the ASHRAE Journal. Decks are disarmingly simple. The ones we are going to deal with have conditioned space under them. They are nothing more than roofs that you walk on. But we tend to mess them up royally.
An edited version of this Insight first appeared in the ASHRAE Journal. This green roof stuff is getting out of hand. It is dumb to do a green roof to save energy. If dirt were energy efficient, we would call it insulation and put it in walls.
An edited version of this Insight first appeared in the ASHRAE Journal. Folks are building houses and retrofitting existing houses with increased airtightness, and this is great. They use a blower door to help measure leakage, and this is also great. But then they think that a blower door actually is a precise measuring tool for how air will leak across the building during service. Wrong.
An edited version of this Insight first appeared in the ASHRAE Journal. It was the ants that finally did it. It wasn’t the shingles that needed to be replaced. It wasn’t the three-dimensional airflow network in the roof assembly. It wasn’t the lack of racking resistance. It wasn’t the lack of thermal resistance. It was the ants. Carpenter ants. There were just too many ants in my renovated barn.
An edited version of this Insight first appeared in the ASHRAE Journal. Engineers are pretty funny people. Engineers say that 1 inch of water exerts a force of – wait for it – 1 inch. Yup, 1 inch of water weighs 1 inch of water. It’s a gift we engineers have. Let me help you all out a little bit here, go suck on a straw and draw 1 inch of water up into the straw.
An edited version of this Insight first appeared in the ASHRAE Journal. The Parthenon was constructed around 450 B.C. as a temple to the Goddess Athena. More recently a temple overlooking Vancouver was constructed by the contractor Gauvin the Younger to honor the God of Building Science Hutcheon. For the past five years the Devout have been sprinkling water on the temple Icons carefully watching the results.
An edited version of this Insight first appeared in the ASHRAE Journal. How hard can it be to insulate a flat sheet of concrete? I mean you only have three choices – on the top, on the bottom, or on the edge. OK, you might have some combination of the three as well.
An edited version of this Insight first appeared in the ASHRAE Journal. Sometimes in order to do the right thing you have to do “a workaround.” I love the “I-Codes.” But they can drive you crazy. I love them because most of the time they are right. In fact almost always they are right. But, every now and then . . .
This Insight was first published in "High Performance Enclosures" by John Straube. Building form and orientation do not have as large an impact on energy consumption as sometimes thought, especially for mid-size or large buildings.
An edited version of this Insight first appeared in the ASHRAE Journal. Too often structural decisions are made in isolation from the energy impacts. It seems to me that folks just are not serious about energy.
An edited version of this Insight first appeared in the ASHRAE Journal. This all started pretty innocuously. I just wanted a client to have a warm floor. How complicated could that be?
An edited version of this Insight first appeared in the ASHRAE Journal. To claim that something that has holes in it can act as a water control layer is a pretty interesting argument. It is both true and untrue.
One of the dirty little secrets that never gets talked about is that water leaks through building papers, building wraps and housewraps and runs down between them and the sheathings that they cover. The water enters through nail holes and staple holes and sometimes just through the field of the material if you have a poor product. The good news is that the nail holes and staple holes don’t leak too much and we know how to handle the incidental leakage.
If you take rocks and melt them and blow air through them you get fluffy rocks. And fluffy rocks don’t burn. If you take gypsum and make it into sheets you get “sheet rock.” And guess what? Rocks don’t burn. Also, metals don’t burn. You can look that up. OK, some metals burn, but you get the idea. If you take wood, which burns, and add rocks and metals to the wood, you get wood that does not burn. We could be on to something here.
