(continued from Building a Green House)
Building a high performance and moisture resistant house comes down to great insulating, great weatherproofing, and controlled ventilation. This doesn’t necessarily mean that expensive and high end products have to be used. Quality, long-term wearability, and low VOC are ultimately more important. In my mind “high performance” equals “green” only if excess energy and harmful chemicals are NOT used in their production.
Cleveland State University says: “A high performance building is one that generates a high return on investment for the environment, the building owners and managers, the human and organizational occupants, and the community.” Pretty straightforward, yet all-encompassing in its vision. The difficult part about this is considering the long term investment in your house’s performance. Do you have the foresight to see you’re energy bills decreased over the next several decades in compensation for installing slightly more expensive, yet efficient, building materials? I admit, it’s extremely tough for most people to spend more money on their building project now for a potential savings in the future. Look at it this way: not planning ahead was a fatal flaw for Neanderthals (hint hint).
There are many products on the market that weren’t around several decades ago that will substantially increase the performance and moisture resistance of your home. Waterproofing products that you can spray, paint, or roll on are the most common. Various kinds of rigid or expandable foam insulation are also great products to tightly insulate you home. Some even have a radiant coating to deflect the sun in summer, and keep more heat in the house in winter.
Let’s start with the foundation. After planning for a final grade around the house to channel water away, but before the back-filling happens, you’ll need to think about waterproofing the foundation. No matter what kind of foundation you’re putting under your building (except maybe piers) you definitely want to keep the water out by waterproofing the exterior of the walls. A common method to do this is to spray or paint on a heavy petro-based waterproofer and cover it with rigid foam insulation like Dow Blue Board (this is becoming “code” in many areas of the country).
Proper drainage under and around the footing that leads to a sump pump in the basement floor is required. It’s the best way to collect and get rid of a lot of water that’s infiltrating next to your foundation. Make sure the plumbing of the pipes, valves, and pumps is up to code. You might even want to double check tightness of connections after the plumber leaves. I had a problem with a slightly loose pipe clamp above the sump pump which resulted in failure of a connection when water started to come through at high pressure. Thanks goodness I was home at the time, other wise the pump would have kept pumping right into my basement! The technology is only as good as the people that install them.
If you’re going with standard stud frame construction, then consider blown or sprayed-in insulation. There’s two main classes (that I’m able to find): spray in foam, either petrol or biobased from soybeans, and cellulose. Frankly, I’ll never do tradition fiberglass bat insulation again. It’s unpleasant to handle, and it’s nearly impossible to get it to completely fill a framing cavity, especially where it has to go behind wiring. It’s not that it’s extremely toxic, but you definitely have to wear gloves (leather is best) and a simple respiratory mask.
There’s also a debate in the insulation industry about the flammability of fiberglass bat insulation vs. cellulose insulation. At first glance you’d think that cellulose insulation, which is ground up newspaper, would be highly flammable. Newspaper is a good way to start your campfire, right? But, the insulation product has a non-hazardous fire retardant added. The fiberglass itself isn’t flammable — it’s silicaceous glass, essentially — but the paper backing is. I even read of one story where a barn was accidentally burned down that had both piles of fiberglass bat insulation as well as bags of cellulose insulation. After the roaring fire the fiberglass stuff was completely gone (to human eyes), but the pile of cellulose was still there with the exterior plastic bags burned away. That’s enough of a story for me.
As for controlling the moisture in your home your best option, after proper drainage and weatherproofing, is a fresh air heat exchanger. This kind of device usually incorporates with a central heating and cooling system. It will take in fresh outside air and passes it through a heat exchanger is order to capture the heat (or cool) already in your house, instead of taking fresh air directly into the furnace which would cost a lot more to heat. If you need to put some moisture back into your home’s air then something like an April Aire system is needed. Not sure if this kind of humidifier can be directly integrated into a standard air-to-air heat exchanger. I’ll have to research this…