Greening Your Home: The Site
Whether they have come to the residential housing field from building new homes, remodeling old ones, weatherizing them, supplying building materials for them, or greening them, more and more practitioners are recognizing the need to see a house as a system and are seeking to improve building performance. But each discipline has a slightly different take on what these goals mean. Having participated in all five of these approaches to creating better residential living spaces over the years, I believe it is imperative that we see how we all complement one another. Through recognizing this,we can help each other find the most comprehensive overview of the creation, maintenance, repair, and improvement of our living spaces.
Persons dedicated to green or sustainable building need to learn that an energy-efficient building envelope is the first step to energy efficiency. By the same token, those creating living spaces that perform much more efficiently need to be constantly reminded that this must be done with materials and systems that do minimal harm to the environment or to the persons living in them.
There are many performance issues related to the site that are relevant for anyone working on residential housing. For instance, how a site is evaluated and prepared, from soil testing to determining how a house will sit on that site, involves choices that will ultimately affect the performance of the house to be built there.
Environmental assessment of a site, soil testing, and even a check with the local Soil Conservation District Office are critical to determine whether there are any preconditions that may affect a new structure on that land or help determine why something in an existing home is amiss. I remember troubleshooting a home where the chimney had dropped off the side of the house and sunk more than a foot into the ground.We later learned that the development had been built over an underground stream and other homes in the development were experiencing similar issues. On another occasion, the smell of oil in a basement was traced to the leaking tanks of an old gas station that had been removed years before. A home’s performance is intimately connected to its site and to the sites surrounding it.
Controlling stormwater, by methods such as constructing a quality stormwater runoff system on-site, is a growing concern where rainfall is plentiful. Keeping stormwater on-site is of equal concern in places where there is little rain. A number of communities have increasingly found that their storm systems cannot handle the load. I have walked on basement floor slabs where I could hear water sloshing just from the weight of my body. The slabs were floating on backed-up stormwater. A sump might help, but the larger issue is overstressed systems. We need to avoid doing harm to the structure or increasing moisture loads on the interior. Rain harvesting and rain gardens are two measures being used more and more. Using permeable paving surfaces also helps reduce the water runoff.These are especially helpful in keeping surface pollutants from being carried to our water treatment plants.
Designing a house, addition, or detached garage so that as much of the roof as possible has a southern exposure increases the potential for generating electricity or providing hot water. Though the cost of alternative energies is high at this time, designing a house so it is ready for such installations when the price is right will enhance the energy performance of the home over the long haul. Recently, while doing the first serious attempt at a green rehab in Cleveland, we had to replace the garage;we then installed the new one with half its roof ready for a solar installation. On another project, where photovoltaics were placed on the garage roofs in this climate, the panels are generating enough electricity to cover the electrical cost of everything on the property except the refrigerator and furnace motors. Effective, but not yet cost-effective.
Retaining trees that provide effective shade and wind breaks on western and northern exposures can reduce energy costs. Keeping landscaping away from foundations can help reduce moisture entry into the basements. Using native plantings and hardy grasses means using less water to maintain them. The American Water Works Association indicates that on the average, Americans use up to 58% of their water for exterior purposes in a time when water is becoming more and more expensive.
Avoid the use of pesticides and herbicides as much as possible on the exterior, because over time they are tracked into our homes and are deposited in our carpeting and other flooring surfaces where children are put at risk to pesticide and herbicide exposure. Pesticides and herbicides can also become part of the soil gases that enter our basements when they are depressurized from the interior.
Every residence we build has an impact on the site and on the sites surrounding it. And how we manage that site during construction and during the time when the house is occupied, can significantly affect the day-to-day performance of that residence.
I’ll be tackling the foundation in the next issue.
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