12 Mar Green Building Science Basics

This week, the third session of Green Boots 2015 at the Austin Home Builders Association focused on building envelope and building science foundations. Our distinguished presenters were Chris Rosewald with BASF Center for Building Excellence, and architects Peter Pfeiffer and David Fransik. And here a few highlights:

Some Basic Tenets of Building Science

1. Tight construction – Seal it up to keep moisture and heat out in Central Texas.
2. Ventilation – Provide appropriate ventilation to expel heat and indoor air pollutants.
3. Optimize the thermal envelope – Want roof and wall layers that minimize heat and moisture gain, but don't trap moisture within their layers. Water will get into the outer layer, or two one way or another so it needs a way out.
4. Right-size air conditioning system – An over-sized system will cool, but won't dehumidify properly due to “short-cycling.”
5. Tight construction + pressure balancing + proper ventilation = moisture management

In general, when you think about where to put the most effort and money when designing a house, you do to the house what you would do to yourself. So, in Austin, it’s hot and sunny much of the year. You want to be in the shade and wear sunglasses. Similarly with a house you want a well-insulated, heat-reflecting roof for “shade” and over-hangs/shades to keep the sun from shining directly into the south and west windows most of the year.