EARTH FRIENDLY CONSTRUCTION Constructing Healthy, Comfortable, Durable, Energy Efficient and Environmentally Responsible Homes and Buildings

People live inside their homes over half of their life and indoors 90% of the time, yet the indoor air quality is 3 to 5 times more contaminated than outdoors. The air we breathe indoors is the most controllable part of the building that can affect our health. Several factors contribute to this less than desirable indoor air quality (IAQ)). Some of which are listed below. It is important to remember that even healthy people that don't seam to notice the poorer indoor air quality may indeed show minor health symptoms like an occasional irritated throat or sinus, general malaise or a nagging headache. Poor indoor air quality may prolong an existing "cold" infection or bronchitis. Young children, the elderly and people with suppressed immune systems are generally inside all the time and must be especially diligent.  Chemically sensitive people are extremely aware of poor air quality and must go to extreme measures to prevent reactions.  Asthmatics must be aware of their allergy and asthma triggers. We have all heard of the "sick building" syndrome.

        Strategy for improving indoor air quality:

1. Reduce the pollutants in the first place.
2. Use fresh air ventilation to flush the indoor air.
3. Clean the indoor air with a quality air filtration system.

Sources of indoor air pollution:

Out gassing of fumes from building materials.

Many types of construction materials release gas contaminants (out gassing) for many years after construction is complete. These materials include  plywood, particle board, cabinets, adhesives, flooring, paint, carpeting, fabrics, furniture, etc. to name a few.

Formaldehyde is the most prevalent chemical that is released. It is used widely in the manufacture of building materials such as particle board and carpeting. Small concentrations can cause eye, nose and throat irritations, wheezing, and skin rash. Higher concentrations can trigger asthma. It has been shown to cause cancer in animals. There dozens of other chemicals also.

In a healthier house, all materials are scrutinized for out-gassing of chemicals and an optimum choice of material is made. There are several strategies for mitigating the release of these chemicals, but the best strategy is to eliminate them as most as possible in the house.

Garages

For better health, you might want reconsider an attached garage. Though it is convenient in winter, the air quality standard inside the house is compromised. Research has shown carbon monoxide levels in the house remain elevated for 8 hours after the car is started in the garage and backed out. This is important if small children or elderly folks remain in the house during the day. Also pesticides, fertilizers, gasoline, oil, paint, paint thinners, solvents, other chemicals, etc. release fumes are always present throughout the house even with the door closed and sealed.
   
Here's how the garage fumes enter the house. 1).The exhaust fans in bathrooms and in the kitchen when operating create a slightly negative pressure in the house that sucks in air from where ever it can including the garage.  It comes in through cracks and holes in the separating wall and the attic (it is hard to seal the attic) and from a less than perfectly sealed door.  2). Same as above but the outside wind pressure is the driving force.  3). Diffusion of gases.

If it is desired to have an attached garage, consider these improvements:

1. Construct a breeze way or enclosed walkway between the  garage and the house with weather-stripped doors on each side with outside ventilation in this separating area. This is only possible, of course, if planned before the house is built.
2. Install a ventilated paint cabinet in the garage on an outside wall to put all the chemicals, paints, thinners, pesticides, and etc. Install two louvered and screened vent holes through the back of the cabinet and through the wall to the outside air. Put one vent high and the other low. Put a weather stripping seal around the cabinet door and keep the door tightly closed. This way the fumes are vented outdoors and not into the garage. While this paint cabinet vents paint fumes it does nothing for car exhaust.
3. Put an exhaust fan with timer in the garage to vent the car exhaust and other garage fumes. If you have a gas appliance in the garage such as a furnace check with building officials before installing.
   

Fresh air ventilation

The new rule is "built it tight and ventilate it right". The best ventilation systems draw outside air from high off the ground and pass it through an air to air heat exchanger. The incoming air is warmed up by the out-going stale air to save energy . The incoming air is passed through filters of 0.01 to 0.3 microns size to remove the tiniest pollutants like pollen and dust. Stale air is  steadily drawn out of the house from the bathroom, kitchen, (even from under the kitchen sink if desired) and bedroom closets. This system is controlled by a timer and uses high efficiency electric motors in the fans. There are many specific scenarios depending on the existing heating system and size of building.  

Point locations of rapidly exhausting stale air are used in addition. These locations are in the bathroom and over the kitchen stove.

Of course, the best ventilation is an open window on a cool summers eve!

Gas appliances

The intelligent decision is to always install direct vent or power vent gas water heaters and gas furnaces because of the risk of back drafting due to kitchen and bath exhaust fans and high outside winds. The proper combustion of the gas flame is greatly reduced even with minute back pressures. Carbon monoxide levels increase thousands of times if the flame fumes are drawn back into the house. 

Carbon monoxide detectors are recommended to be installed near every gas appliance. Think about a tree branch causing unseen damage to the outside vent or cap.  The famous Ellensburg wind can create unbalanced air pressures in  buildings.

Mold, mildew and condensation

Mold and mildew strive on wet surfaces. Eliminate the moisture and you eliminate mold and mildew – easier said than done. The worst and most insidious moisture problems are deep in the walls, above the ceiling, and/or  below the finish flooring where you can't see it until there is a structural problem like the ceiling falling down or the wall or floor buckling. Proper workmanship of the initial construction is imperative to prevent these problems and well as correct use of materials..

Moisture moves through walls, ceilings, floors in three ways.

1. Air leaking through a wall carrys moisture with it. Depending on temperature gradient inside the wall, this moisture can condense just like your breath on a window pane. Attention to construction detail is a must.
2. Diffusion of moisture. Water molecules diffuse their way through the wall material. They travel in the same direction as the heat flow and in fact are driven by the heat. Good quality sealer and enamel paint can greatly reduce diffusion.
3. Flowing liquid water from leaks in the roof, shower pan, plumbing, window flashing, etc. Again construction workmanship and details are all important.

There are many strategies to prevent moisture from getting into the walls and ceilings – the first line of defense is a good enamel paint on the room side of the surface along with proper ventilation. The second line of defense is allowing the moisture that has entered a wall, ceiling or floor to dry to the outside.

Floors are damaged mostly by liquid water from leaky plumbing, spillage, failed caulking and proximity to ground moisture.

Carpeting

Carpeting traps dust, dirt, mites, pollen, etc. Carpeting is a source for asthma and allergy triggers. When you walk on it, these pollutant are stirred up and are drawn toward your face by the warm air convection surrounding your body. Research has shown airborne particle concentrations can be 3 times higher around your mouth and nose than in the air that is away from your body. In a small way, it’s like you’re vacuuming the carpeting with your nose!

In the average house with an average age carpet, if you could magically make the carpet and pad disappear but leave the dirt – you would have a layer of dirt about 1/8" thick across the floor!

Hardwood floors are easy to clean and last for over a hundred years. Though initially more expensive than carpeting, when measured over time hardwood floors are cheaper.

A good compromise is to have a hard surface floor with area rugs that can be taken outside for shaking and cleaning.

Good choices for earth-friendly flooring is certified hardwood, bamboo, linoleum and ceramic tiles.

Vestibules, entrances, and mud rooms

At the entrances to a house there should be a place to wipe off your boots/shoes or better yet remove your outside footwear. Ideally, this place should be a vestibule or mud room where there is an outside door and an inner door – that way this rooms stops the rush of cold outside air coming in and the warm inside leaking out. This room could have a heater to dry snowy or wet clothes. The outside dirt and contaminants remain here and are not brought into the house. Energy efficiency, health improvement and practically in one room

Radon

Radon is not considered too likely a risk in central Washington. You never know for sure unless you test for it which is easy and cheap. While the house is being built, it is easy and cheap to install a plastic ground cover in the crawl space to vent any radon/moisture/ground gases to the outdoors . It’s like cheap insurance. Remember what’s in the air in your crawl space is also in the air inside your house.

Free tip!

If you read this far congradulations.  Here's a free tip. The two things one can do to improve the indoor air quality that is absolutely free -

1.  No smoking.
2.  Take shoes off at the door.