Understanding Building Science

Building science is about understanding a house as a system and knowing how all the components of a house work together. This month Carl Seville, CR, owner and president of Seville Consulting, and Paul Raymer, chief investigator of Heyoka Solutions, LLC, lend a hand in explaining building science.

“I think that in order to understand how components work and how one element affects another one you have to understand building science,” says Raymer. “That relates to just about everything, like how green building is holistic building, and how that works with building components. I think a lot of building component manufacturers look at their element as a solution to a single problem rather than at the whole science of the building.”

Building science is essentially the management of heat, air and moisture in buildings. Heat refers to heat loss and gain where it is important to keep a home cool in summer and warm in winter. Air is the movement in and out of a home as well as within the building. Moisture describes bulk moisture, including rain water and leaks, and moisture vapor which is created inside the house from human use and interaction with the house or moisture driven into the house from outside.

“I look at remodelers as being problem solvers,” adds Raymer. “They come in and talk to the homeowners about the problem they want solved, and it’s vital the remodeler understands how all of the components work. You can’t solve a problem like a dry house by simply putting in a humidifier. It’s probably too dry because it’s too leaky and has too much infiltration, and if you put in a humidifier you’re going to cause a significant amount of other problems.”

One of the problems with homes is that most homes are wood built and are very susceptible to moisture. Also, because of varying climates in the United States, different areas have to build walls differently to deal with things like moisture.

There are three ways that heat really moves in and out of a house: conduction, convection and radiation. Conduction is heat moving through a solid. So if it’s hot outside and cold inside, the heat moves through the walls because heat always wants to move from a hot area to a cold area. The key is to stop that from happening, usually with insulation.

“What is even more important in some climates is convection, which is heat movement through the air,” explains Seville.

“What I’ve discovered in my work is that air leakage is almost more critical than insulation in some situations. What happens is that fiberglass is our typical insulation, and it doesn’t stop air; it only stops heat, and it only stops heat if it’s enclosed and air doesn’t flow through it. If fiberglass isn’t installed properly, there can be a lot of air leakage, and it doesn’t insulate properly.”

One thing Seville recommends to avoid this problem is using a spray foam insulation since it stops air movement as well as heat. He also states that fiberglass is also only effective if it’s sealed off on all six sides. While it’s usually sealed off properly, the problem is, every time a receptacle, an outlet or a window is added, it creates a circumstance where the insulation is no longer properly sealed off.

Radiation is heat moving from surface to surface. That takes place mainly in the summer and is usually heat trying to get into the house and rarely heat trying to get out of the house. This can be seen from roofs and windows as heat hits the roof, heating the attic, or hits a window, heating the house. To prevent a house from getting too hot, it’s important to shield the house from some of the radiation by using radiant barriers or putting in high-performance or shade windows.

“The next big frontier for remodelers is to understand building science,” says Seville. “Instead of going into a house and just doing what the client wants you to do, go in and do some performance testing. There’s some good equipment out there, and there are trained specialists to do this work as well. For a few hundred dollars you can have someone do a blower door test, a duct blaster test and some physical investigations to give you a report that lets you know what the defects are that need to be fixed.”

A lot of advanced remodelers are testing homes and then sitting down with their clients to look at some of the problems and talking about the long-term issues.

“People tend not to want to spend money on the things that aren’t visible,” adds Seville. “They would prefer to spend it on granite countertops and appliances. Part of the hurdle is that homeowners aren’t aware of the problems, but it’s like driving around a nice Mercedes with a leaky sunroof, bad exhaust and a terribly out-of-tune engine.”

A great way to implement building science in a business is to find someone who can do the testing and evaluation or have someone in the business learn to do, which includes education and purchasing some equipment.

“There’s so much to learn in relation to building science that it’s amazing,” explains Raymer. “There are good programs and conferences, and there are organizations like the Building Performance Institute that do training. Remodelers need to be trained in building science to grow their business and to protect them from mistakes.”