Thursday, August 19, 2010
Green building is about much more than the house itself. The location of the home is important, and using the home as a tool to educate the public about the benefits of green building is also critical.
The process by which a home is built also determines whether a home can be considered 'green.' Site management, erosion control and tree protection are some examples. Recycling is another, and the focus of this blog post.
Prior to making a commitment to building green homes, I typically looked at construction waste management from a cost perspective; ie I would use whatever approach resulted in the lowest cost. If I had a big lot to work with, I'd usually get a 30 cubic yard construction dumpster, and every trade would throw all of their trash in it, regardless of whether the waste might have a second life. As a bonus, neighbors would inevitably take advantage of this big, free (to them) trash container and throw in old furniture, bikes, and anything else left over from the yard sale.
LEED rewards builders who manage construction waste effectively. The first part of managing waste is to minimize waste. Order what you need, not more. Use scrap effectively. I remember on the first LEED-certified home we built I drew out a cutting plan on the floor for the drywall team. This plan showed where full pieces would be used, and if a full piece had to be cut, I even identified locations where each piece of scrap could be used. Granted, the hangars looked at me kind of funny, and we didn't get 100% of what I wanted, but we got part of the way there. We ended up with much less scrap than usual (drywall is a great story which I'll blog about later).
Inevitably, there will be waste. What LEED encourages you to do is to segregate your waste into streams that can be recycled, and those that cannot.
We use small construction dumpsters from Mercados Construction Cleanup of Huntersville. We dedicate one dumpster to scrap lumber that can be recycled (essentially non-treated lumber). Signs in English and Spanish identify this dumpster, and we review it with each trade.
In addition to lumber, we recycle cardboard, drywall, and plastic bottles. I found that on the first LEED-certified home we were able to recycle about 38% of our construction waste. What's more, because of our focus on waste management we actually spent less money in this area. To me, that's the beauty of green building: learning to do more with less.
Sunday, August 15, 2010
It's pretty basic building science that moisture is not a good thing. The combination of wood and water can lead to not only structural issues, but health problems as well.
Minimizing moisture is a key part of durability. The crawl space is only one part of the house where moisture is a concern, but it is the most obvious.
Since 2008 John Marshall Custom Homes has been installing sealed and conditioned crawl spaces on all of our new homes (except those on basement foundations, of course). While nothing is an absolute guarantee that a home will not be subjected to moisture, using sealed and conditioned crawl spaces greatly reduces the opportunities for moisture - and mold - to occur.
The photo above shows the foundation of a new home we are building at 631 James Alexander Way in Davidson, NC. The preliminary stages of the sealed and conditioned crawl space have been installed, including insulation around the foundation walls, and a vapor barrier on the ground and piers. The vapor barrier that is presently installed is a 6-mil temporary barrier which will be replaced by the final 20-mil vapor barrier towards the end of construction.
Later, the wood framing band that sits on top of the foundation walls will have spray foam insulation applied. This type of insulation provides not only insulating properties but also a tight seal against air infiltration. A conditioned air duct will also be run to the crawl space.
To constantly monitor the humidity levels in the crawl space, we will install a humidity sensor in the crawl space and put the display in a prominent location in the house. We also educate the homeowner about the importance of moisture control, and steps to take if the humidity in the crawl space is outside of a desired range.
We've built many homes with typical vented crawl spaces, and have not had issues with them. But, the sealed and conditioned crawl space provides many benefits, and at John Marshall Custom Homes we have decided they are well worth the investment.
Framing on this LEED-certified home starts on August 16. Please check back soon for further updates as the house starts to take shape.
Tuesday, August 3, 2010
Durability management is about as exciting as it sounds. I remember a few years ago I would always meet prospects on the front porch of a house and start to discuss all of the structural advantages of our homes. I could see their eyes glazing over with that 'just show me the damn kitchen!' look.
I've changed my approach a bit now. But, durability is still important. The shine of that lovely kitchen wears off quickly if you're always dealing with maintenance issues.
Part of the LEED for Homes certification process is to have a set of defined strategies to enhance the durability of the home, and to have a third party verify that those strategies have been implemented. Things like kick-out flashings, keeping the foundation at least a foot above grade, insulating all hot water lines, putting ice and water shield in roof valleys...they're not sexy, but they help a home not only outlast it's present owner, but a few generations after as well.
One of the premises of a green home is that they are less resource intensive than a standard home. If a house is built to last for 150 years, that obviously uses fewer resources than building a home that will only last 50 years.
Having remodeled several homes that were not constructed with green building standards, I can tell you that even after 10 or 15 years they start to require significant maintenance, and by the time they reach 50 they're about at the end of their useful life. I confident that with proper homeowner education (another part of the LEED process) and maintenance, our LEED certified homes will last 150 years if not more.
Today we poured the footings on our next LEED certified home. As the picture shows, we use steel reinforcing bar ("rebar") in our footings. This steel bar greatly strengthens the concrete footing which is the support for the home. The result is less settling, and greater stability over time.
One of the things I look forward to when I'm much older is going back to the homes I've built and seeing how they've stood the test of time. Undoubtedly they'll weather the years better than I. Although by that time I may be well past my prime, it will be gratifying to see that our homes are still going strong. Durability management is what will make it happen.