Why are we using a coal waste byproduct?

Some readers of this blog might be surprised to learn that we are incorporating coal fly ash, a waste byproduct from coal combustion, as a building material in our home. At first it sounds a little scary—before environmental protections were in place, fly ash was routinely emitted into the atmosphere, exposing people to chemicals and heavy metals. Now, coal plants capture coal fly ash using pollution control technologies and it usually ends up in landfills where it can put water sources at risk of contamination.

But lately, more and more fly ash is being recycled, often locked into place as a replacement for some of the Portland cement in concrete in construction projects. Portland cement is a common and inexpensive building material, but its production is extremely energy intensive and frought with environmental issues. Using fly ash in place of some of the Portland cement reduces the environmental impact as well as the carbon footprint of the concrete. In fact, the U.S. Green Building Council awards LEED points for using coal fly ash (Materials & Resources Credit 2.2, Environmentally Preferable Products: "Foundation: Cement"). For those of you who are still wary, the U.S. EPA ruled in December 2014 that coal fly ash can be safely used as a component of cement and gypsum wallboard. This fall there has even been a local shortage of fly ash and our builder, Morrissey Builders, wasn't sure they'd be able to find any!

We're glad to be keeping waste out of local landfills and crossing our fingers we won't have any delays due to the shortage, since the cement footings are scheduled to be poured as soon as it's warm enough outside for the cement to set! We'll keep you posted.