Wednesday, July 29, 2009
I must admit, when I think of concrete, Green is not what comes to mind.
In fact cement production is extremely energy intensive; some estimates calculate it contributes as much as 7% of global carbon dioxide emissions. Demand for cement worldwide continues to grow, with more than 3 billion tons produced each year.
Several cement manufacturers are advertising "green" cement formulas as an alternative to the standard quarried cement mixes of the past. But questions still remain as how "green" they really are.
Basic cement is composed of six components: Cement, coarse aggregate (rock), fine aggregate (sand), water, fly ash, and chemical admixtures (for different specialty applications).
Green concrete formulas support their environmental claims in two principal ways:
1. Using recycled aggregates
Green concretes often contain a percentage of coarse and fine aggregates rather than digging up virgin materials. This is slightly greener due to the reuse of the otherwise quarried materials, yet the processes involved in preparing these recyclables often use a comparable amount of energy (and fossil fuels) to produce.
2. Fly ash
Here is the sticky wicket. Fly ash is a waste byproduct from the chimneys of coal fired power plants and is composed primarily of silicon dioxide and calcium oxide, but may also contain a range of other toxic compounds. Before governmental mandates regarding air quality, this fly ash was released into the atmosphere. Now, much of it is captured and placed in landfills. This creates new environmental challenges, as evidenced by the Knoxville, TN coal spill that occurred earlier this year.
The concrete industry uses a higher percentage of fly ash in Green cement mixes than in standard concrete. Trade organizations and certification programs in green building are touting this as a great benefit, since using fly ash in concrete diverts it from landfills.
However, we still don't understand the possible health risks associated with using higher quantities of fly ash. To date there have been no environmental standards adopted for the use of concrete mixes with a higher percentage of fly ash.
Buyer beware when choosing Green concrete! In my next post, I will discuss the pros and cons of this concrete and safer options for the use of these products.
Tuesday, July 21, 2009
Welcome to "Choosing Green"; a blog about the daunting world of Green building and construction.
I've been in construction and remodeling for as long as I can remember. I've also grown up with a reverence for nature and environmentalism.
Recently, the building industry has undergone a dramatic transformation. Driven by a few visionaries, adopted by architects, and fueled by consumer demand and public policy, the construction industry has finally grown a conscience.
What this has done is presented the average homeowner with a daily deluge of new products and (buyer beware!) product claims that aim to capitalize on our interests in remodeling our homes in a way that won't harm us or our environment. This has left most of us wishing to "go green" with the question, "Where do I begin?".
That's why I've started this blog. The mission of "Choosing Green" is to help people take Green building one step at time.
Green Doesn't have to be Expensive.
You don't have to completely strip your home and rebuild with "green" materials (although the industry would love it if you did). In fact, this would only be contradictory to Green principles; preserve your resources, remodel only what is necessary to complete your project. Unless you're building a new home, you've already harvested the materials to create your space. Remember, in green, less is more.
Green Doesn't have to be Technical.
You don't need to have a master's degree in bioengineering to make green choices when remodeling your home. Nor do you have to employ the latest innovations in manufacturing to benefit from Green practices. In fact, much of Green theory is common sense; ancient wisdom that has long been available and only been overlooked since we opted to focus our innovation on capitalizing on the "low-hanging fruit" of fossil fuels.
However, you do need to know what's available. And you need to know what's an outright scam. You also need to know about the pro's and con's. This blog is here to help.
Green Building is about Choices.
Every day there are more Green options available to us. No one solution is ideal for all situations. Green building is most effective when the individual circumstance is taken into consideration. Each of has much to consider when making decisions about remodeling; style, function, budget, health, environment, maintenance, etc... Green building is about knowing what alternatives are available to you and what works for your situation. It's about asking questions and doing what you can within your means.
Green is incremental.
Remember when curbside recycling began? At first, all you could recycle were glass and soda cans. Now, millions of tons of reusable materials are diverted from landfills every day from the daily efforts of people like you and me. Building Green can work the same way. Small decisions can have a big impact if each of us pitches in. We didn't pollute the planet overnight, nor can we do the same to save it. In the aggregate, our choices as consumers will change the planet and preserve it for our children.
Future installments of this blog will explore choices for homeowners and anyone remodeling a home. I'll weigh the pros and cons of solutions, dispel myths and praise options that we can all take advantage of. Most of all, I hope to inspire you to think Green!