Green Home Design & Construction
New construction provides many opportunities to apply green building practices. Besides providing better indoor air quality and higher energy efficiency homes, you have the opportunity to help the environment.
Many new construction homes are being built green. In 2012, 42% of new construction homes built in Seattle were built green. As of September 2013, we’re at about 43%, but building green is becoming more mainstream through education and awareness.*
The more common green building becomes, the more affordable it is. Depending on the choices you make and the experience of your builder it could cost approximately 2-5% more. Some builders say they can build a green home for the same cost per square footage as a traditional home because by implementing green building techniques from the beginning you save money on the design.**
One of the first steps when thinking about building new construction is site orientation & design. The way your home sits on the lot is extremely important. Where your house sits compared to the sun can drastically reduce heating and cooling costs, give you more light, and increase the marketability and resale of your home. You can still build a deep green, high performance, super insulated home even if your house doesn't face south. Ideally, the roof line of your house should face south to capture maximum sunlight.
A homes building envelope requires the largest quantity of materials compared to any other part of the structure. When building new construction, you have the opportunity to use building techniques such as advanced framing which reduces lumber needed to frame a structure, and allows deeper insulation to fill the walls and reduce thermal bridging. Thermal bridging occurs in a home where materials used had poor insulating properties.
Interior systems are a critical element in green home design. It is common for people to believe that you don’t want a tight home because it needs to breathe. But if you make it tight, you have to insulate properly.
A tight building envelope requires a ventilation system for indoor air quality and moisture control. If you do advanced framing and deeper insulation, you will likely not even need an additional heat source because your body heat and movement along with the fact that no air is leaking from the building and it maintains temperatures.
Ventilation can be achieved by having a Heat Recovery Ventilation System (HRV). These bring fresh air into a building & improve climate control. The job of an HRV system is to keep heat in and move stale air out. They normally have two fans, one to take out household air and the other to bring in fresh air. This is done in the heat exchange core. It takes the heat from the air leaving the house and transfers it to the fresh air coming into the house. The air streams never mix but the heat is transferred and comes into your house at the temperature you have it set to.
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SUSTAINABLE BUILDING MATERIALS
Using sustainable materials in new construction is making all the difference. The Green Building market segment as of last year was $85 billion in the US. According to McGraw Hill’s Green Building Outlook report this number could triple by 2016.***
One thing to think about when selecting green building materials is whether or not they have toxins in them. While it’s important to select materials with low toxicity, it is also important to keep in mind the embodied energy of a material when looking for sustainable materials. Embodied energy is the total of all the energy inputs over the lifetime of the material. The lower the total embodied energy, the greener the product. An easy way to think of this is the before, during, and after steps of a product. Some ways to determine embodied energy are if it is local, if the procurement of the material is environmentally friendly, transportation distances, installation, and if it is recyclable.
A very important aspect of this in my opinion is regional sourcing. Besides lower embodied energy, local materials are also better suited to climate conditions and help to support local economies. It’s not always possible to use local materials but you should start locally before looking regional, within the US, then North America and lastly look overseas.
Some regional materials used in green built homes in the Northwest are ponderosa pine and western hemlock because they are a readily available resource. Builders have used locally milled alder, fir, cedar and other wood for finish wood, siding, framing and fencing. Green builders are also using American Standard Toilets because they are one of the few plumbing manufacturers whose products are made entirely in the US.
Some materials that are recycled and made into sustainable materials include:
- Reclaimed saw dust made into composite flooring
- Shredded paper & cardboard that’s Waterproof building sheathing
- Floors and countertops made from recycled glass
- Decorative tiles with crushed seashells
- Denim, sand, newspapers & cardboard used as Insulation
- Alternative decking materials
- Recycled content carpet. (Less than 1% of carpet is recycled but 60% of carpet
made here is a recyclable nylon that can be put back into carpet or raw materials.)
- Concrete is one of the most environmentally friendly products around.
- Fly ash from coal burning power plants, metal, concrete, bricks and asphalt for fill
material, residue from the manufacture of asphalt shingles for the making of
porcelain tiles, drywall scraps to make new drywall (25% - 50% recycled content)
Many people might not know these things can be utilized:
- Pine from beetle infested forests
- Hand forged locally produced bathroom hardware that doubles as grab bars
- Rubio Monocoat floor finish
- .5gpm flow restrictors for bathroom sinks
- Tight-knot cedar exterior trim
Besides the many materials that are made from recycled content, reclaimed materials are also very popular in green building. Sometimes they can be very sought after and rare items such as marble mantles, old growth hardwoods or antique fixtures.
MANAGING CONSTRUCTION WASTE
Green construction includes a plan for managing waste.
According to the National Association of Home Builders, a 2,000 sq. ft. home generates up to 8,000 pounds of waste. Without a waste management plan, most of this winds up in landfills. But builders should be able to recycle 85% of its waste because it’s made up mostly of wood, drywall and cardboard.
Money can be saved on building a home by having a waste management plan. It does brings down the cost of construction as you don’t over order. Some vendors even have a buy back program. You also have an impact on reducing greenhouse gas emissions because less materials are manufactured. 40% of the nation’s waste is from construction sites according to the EPA.
Some materials that can be recycled or salvaged are:
- Asphalt pavement
- Concrete
- Gravel and aggregate products
- Masonry scraps
- Metals
- Clean wood
- Plastics
- Insulation materials
- Un-tempered glass
- Door and window assemblies
- Carpet and carpet pads
- Ceiling tiles
- Plumbing fixtures and equipment
- Cardboard
- Appliances
- Brush and trees
Some tips on reducing construction waste are to:
- Have a waste management plan from the beginning and only order materials needed
- Work with suppliers to limit packaging. If you use multiples of a material that come
individually packaged, special packaging can be arranged
- Use a supplier that has a buy-back policy
- Contact local recycling centers such as Habitat for Humanity who will take reusable
materials
LOW IMPACT DEVELOPMENT
It is important to have low impact development. As communities grow, so does the amount of surface area covered by roads, roofs, and parking lots. Low impact development is a sustainable storm water practice that helps manage runoff. This focuses on the conservation and incorporation of the sites natural landscape features.
It creates functional and appealing site drainage and uses storm water as a resource rather than a waste product.
Rain Barrels catch rainwater for irrigation use. Other examples are:
- Rain Gardens and Bio swales – collects storm water runoff from roofs, driveways and
other impervious surfaces
- Veggie Roof Tops- absorb rain water and reduce energy costs
- Permeable Pavement- roads, parking lots, driveways, sidewalks, to allow rainwater to
seep through which prevents soil erosion. These are black pavers, porous asphalt or
concrete and grid systems
* (Research done by Green Canopy Homes through NWMLS data)
** (USGBC.org)
*** (http://www.construction.com/about-us/press/green-building-outlook-strong-for-both-non-residential-and-residential.asp)