Does a house need to breathe? What a question! Probably one that has sparked more controversy in the construction industry than any other. Here are 5 reasons you need to Build Tight and Ventilate Right.
Codes. New houses today need to meet more stringent building codes than they did 30-40 years ago and for good reason. Every builder knows that to get away with as little as possible in this regard only asks for trouble down the road.
Energy loss. It’s been said and documented that up to 40% of energy consumption is because of leaky houses. Most new construction air tightness codes fall somewhere in the 3-5 ACH (air changes/hr) range. That simply means that the entire volume of air inside a building is replaced/exchanged 3-5x per hour as demonstrated by a blower door test. (Many times, you can actually get much less than that with a few simply procedures.) Also, pressure differences from top to bottom of the house means that warm air escaping out the top is simultaneously drawing cooler air at the bottom. Since any temperature air always carries moisture to some degree, mold and rot is inevitable wherever that air finds different temperature surfaces.
Moisture sensitive materials. Gone are the days of building houses out of solid wood. Those that are built well are often very structurally sound a hundred years later, but terribly inefficient in terms of energy usage. Tearing into some of these old cavities can reveal wood or products with very little damage simply because air passed through and dried things out. In todays industry, we’re using things like OSB, drywall, & mdf…all products that have a high “hygric buffer capacity” which is the ability to retain moisture. Engineered lumber is making technological strides to mitigate this, but is still fairly vulnerable to moisture. The problem lies in making more efficient building envelopes, but with cheaper materials. Ideally, you want as airtight an envelope as possible with higher quality materials that resist moisture such as Huber’s Zip System sheathing or Low-E’s reflective foil.
Ventilation. We DO want houses to breathe, but on our terms. Just like our bodies intake air at one location and then filter and distribute that oxygen, we want HVAC systems that incorporate fresh air from the outside and stream it through the house properly without having it go and come through penetrations in the building envelope.
Comfort. Lastly we want that air coming in to be as pure and free from contaminants as possible, ensuring a happy, healthy, and even sterile environment for us to relax and call home.
Summary: Build Tight, Ventilate Right. With a Birch & Beam home, you can rest assured that many details like energy efficiency and airtightness are not just afterthoughts. They are an integral and well-taken-care-of part of the building process. We do this by using quality materials, sealing every penetration, caulking between plates, and installing numerous types of air & moisture barriers throughout the building envelope.