Green Building Techniques

Build for Passive Solar Energy

http://www.weloveaustin.com/ - Roselind Hejl

Passive solar design for natural heating and cooling is practiced throughout the world under all climate conditions. As energy costs rise, it is critical to use building orientation, window placements, stone floors, roof overhangs, reflective barriers and other techniques to control natural solar energy. In warm climates, face the broad side of the house to the north or south, to avoid excessive heat gain as the sun rises and drops in the horizon. Use deep overhangs or solar screens to shield glass areas from direct sun. Avoid skylights or greenhouse rooms, because they allow too much heat gain. In colder climates, solar heat can be captured and stored in materials such as concrete or stone to be slowly released during the evening.An open floor plan optimizes the effect of passive solar heating or cooling. Doors and windows should be placed to catch the prevailing breeze and allow cross ventilation. Lower inflow windows and higher outflow windows keeps air moving, as hot air rises. A thermal chimney uses a hot zone, such as a glass cupola with windows or vents, to create rising air currents to pull air through the building.Double glass panes provide an insulating air space between the panes, reducing heat transfer. The metal oxide coating on Low-E (emissive) glass helps to keep solar heat out, and interior heat in.


Ventilate attic spaces.

In hot climates, attic spaces can accumulate heat, transferring it to living areas below. AC ducts located in the attic will absorb this heat. In cold climates, moisture can accumulate in unventilated attic spaces, causing wood rot or mold.Continuous eave and roof ridge vents will create natural air flow through the attic. Air enters through the eave vents, and moves out through the ridge vents. As heated air rises, it ventilates the attic. Lighter colored roof materials absorb less heat. Reflective heat barriers on the underside of the roof deck help to reduce heat gain. High levels of insulation in attics and exterior walls is crucial for comfortable indoor temperature in all climates.Some research is being done on building sealed, highly insulated attics.

Optimize your heat and AC systems.

An oversized system will cool too quickly, and leave the room clammy. Smaller systems run long enough reach the desired temperature, and, at the same time, clear the air of humidity.A smaller system lasts longer, does not cycle on and off frequently, and costs less to purchase. Check for leaks in duct work joints, and around windows, doors, attic stairs, exhaust pipes, recessed lights, and electric outlets. Ongoing maintenance of central air systems is necessary to prevent air loss.Use programmable thermostats to regulate your energy usage. Use Pleated-Media Filters in AC return-air grills. This filter removes particles as small as mold spores from the air that is drawn back into the AC blower, keeping coils cleaner and improving the air quality in your home. Heat pumps on electric furnaces reduce energy use by drawing heat from outside air, using the same technology that air conditioners use to remove heat from indoor air. Check with your utility provider for free diagnostic testing and rebates for high efficiency AC systems, insulation, solar screens, and weather-stripping.

Reduce water needs.

Native landscaping that is suited to the rainfall in your area is fundamental to building green. Keep as much native growth on your lot as possible.Water pervious materials such as crushed granite or open paving blocks allow water to percolate into the ground. Rainwater catchment systems use gutters and barrels to catch and store water that falls on roofs. Front loading washing machines use less energy and water. Some dishwashers use less water and have no-heat drying. Check water and energy usage before buying appliances.Low flow toilets and shower heads reduce water usage. Reduce water and fertilizer needs by re-cycling yard waste and leaves for use as mulch.

Use renewable or recycled materials.

Consider decks made of waste wood and plastic, such as Trex or other brands. Medium density fiberboard (MDF), a wood product used for interior trim and doors, does not contain formaldehyde.Fiber-Cement siding, trim, and pipe materials (Hardie Board) are very durable, rot resistant, and fire retardant. Use locally produced, and easily renewed, materials when possible. Consider alternative building materials, such as rammed earth, straw bale or insulated concrete panels.Concrete floors utilize the foundation material as finish floor, saving materials and labor. Recycled wood floors are a very attractive re-use of materials. Bamboo floors are made from a rapidly renewable source - bamboo is a grass that can grow several feet per day. Hard surface floors do not hold dust, molds, and allergens, and are very durable. Use materials with recycled content when possible, such as cellulose insulation, Thermo-ply, and lumber composites. Plan for a place to re-cycle household trash, such as a storage bin in the kitchen, and holding bin in the garage.

Use Safe Materials

Trees, vegetation and bird habitat on the site should be protected during the construction. Native trees, grasses, rock outcroppings and natural drainage can be made a part of your building and landscaping design. Reduce the impact to the building site as much as possible. Make sure construction waste is properly disposed of, especially paints and solvents. Do not allow them to be buried on the site. Use products that are biodegradable, non toxic, water based, and cold water compatible. Avoid products that contain dyes, ozone depleting chemicals, heavy metals, formaldehyde, or known carcinogens. Avoid solvent based finishes, particleboard, adhesives, some carpets, and other products that release volatile chemicals into the air. Look for green rated labels on carpets and other products. Remove old-style pressure treated wood when possible, especially in play structures. Green building is an approach to design and construction that respects the environment and conserves resources. It is a common sense approach that is available to all home owners. Green building techniques create a more cost effective, enjoyable and sustainable home to live in. http://www.weloveaustin.com/ - Roselind Hejl

A Solid Green Foundation

A Green foundation is the point at which your home connects with nature. We’re talking: cold, moisture, and pests. You can deal with much of the cold aspect by using good sealants and thorough caulking. This is not a typical concern for a new homeowner, but as a Green home builder, you will want to monitor everything, especially where energy loss can occur.
Trying to include recycled materials in the foundation of your green home can also make a huge difference in cost and in your impact on the environment. Persuade your builder to work with you on locating recycled CMUs or at least using recycled concrete aggregate as a coarse fill below grade. (Take care to avoid moisture problems around your foundation; this is nothing new to green home building.) You can also specify recycled content in your concrete, such as fly ash and slag. Take this opportunity to install insulation for your concrete forms.
To avoid pest problems, and the later use of environmentally harmful pesticides, make plans now. Use permanent pests shields – especially termite shields – around the perimeter of the house. Employ plastic and metal dividers and fasteners to separate wood and concrete along the perimeter of the foundation from the surrounding ground.
And while you’re at it, protect your foundation from invasive roots by moving your shrubs and trees at least 3 feet from the house perimeter. A green home or any other can’t be happy without a sound foundation. These efficient building practices can be applied to any house plan.

Efficient Floor Plans

Not every pre-designed or stock home plan comes with "Green" features and Energy Savings.
But, you can easily add features and products to the plan to make it "Green" and efficient. You can also incorporate "Green" ideas in the planning stages beginning with your site work. For example, the first thing to consider is how your new home should be positioned on your lot. This is sometimes referred to as the "smart" or intelligent “Siting” of your new home. On every conceivable lot, there are bearings in which to face the house for improved energy performance and thus increased comfort. The primary objective should be to plan the site in regard to the path of the sun. Also to be considered are prevailing winds, but to a lesser degree. The next thing you should consider is perhaps changing the exterior wall thickness from 2x4 studs to 2x6 framing. While the additional strength of the thicker wall would be a plus, the big benefit for your family will be the extra insulation, and the reduced energy use for the life of the home. However, there are now certain types of insulation that can give you higher R-values in 2x4 construction which equal that of 2x6. You should consult with insulation companies regarding this. You might even want to change your house plan to specify Structural Insulated Panels (SIPs) in the construction of your outside walls. The energy performance of these products is miles ahead of stud framing of any kind and should be a “Green” change to be considered. So, the simplest and most effective measures you can undertake to "Green up" your house plans are: Site the house "smart" in relation to the sun, and revamp your exterior walls to either SIP's, 2x6 construction, or new types of insulation so that additional R-values are part of your home’s future.

Selecting a Green Lot

So you're ready to build that efficient and environmentally friendly home. First things first… Do you have a lot to build on? If not, I suggest you get one first. It's best to purchase a lot before you commit to a specific house plan. In most cases you can modify any house plan to fit your lot, but, it's much more difficult to find a lot that will always accommodate a specific house plan. Think about your lifestyle when choosing your lot. Do you have children? Do you have a green thumb? How much yard are you willing to maintain? How important is it to be close to schools, grocery stores, and work? These are important questions to ask yourself, as the old saying goes ... location location location.
Now lets look at the lot. How is the land situated? When choosing a lot with "green" objectives, you will want to take the path of the sun, the corridors of the wind and the slope of the land into your primary factors. Considering how the sun rises and sets on your lot will help you decide on which side of the house you want certain rooms to be, such as a sunroom or screened porch.
Many experts will agree that a gently sloping lot, with a south-facing slope, would be ideal. If your house was located midway between the top and the bottom of that slope, it would be all the better, as you would avoid winter’s cold blast from the north. If you can determine the direction of the winter and summer winds (they usually come from different directions), you can incorporate that into your selection process; since you will want a lot where you can divert or block the winter chill, but channel and exploit the summer breezes. Save as many existing tree's as possible. Trees provide shade in the summer months, but help block cold winds in the winter. Knowing what kind of views you have will also help you select a house plan that will take advantage of the natural setting of the lot. So, Choose a house plan that will best compliment the natural surroundings of the land.

Building Green

Today the Green Building movement is bigger than it has ever been. The environment is precious and anything we can do to help is worth doing. Aside from saving the environment, there are also other benefits from building a green home, a better insulated home will save hundreds in utility bills alone each year. The comfort of being cool in the summer and warm in the winter sounds good too. One thing to remember is that building green can be costly but living green is not.
Most pre-designed house plans you find today, whether it's from a book or even a plan you find at Living Concepts Home Plans is not going to be green by design. Building Green is not just about the plan, it's about how you build the home and the materials you choose to build with. These factors will make the biggest impact on how green and efficient your home will be. Let's face it, the Green Movement is here to stay. So, stay tuned! My next series of blogs will address things that can be done during the building process to build a green and efficient home.