As you plan your home building project, keep in mind that it's also important to use vapor barriers and ventilation to maintain a healthy balance of air and moisture movement throughout your home.

Vapor barriers

During cold weather, water vapor from the warm inside air travels through unsealed holes and cracks, and condenses on cooler surfaces, including exterior walls, the underside of the roof and within insulation.

This condensation can rot wood framing, blister paint, ruin insulation and damage the roof. Vapor barriers installed between insulation and interior surfaces can help prevent this problem.

Your builder should use insulation faced with kraft-paper or reflective foil, and/or install four- or six-millimeter thick polyethylene.


It may seem like attic vents defeat the purpose of insulation, but they're a vital part of keeping fresh air circulating throughout your home.

An unventilated (or under-ventilated) attic can trap heat in the summer months, raising the indoor temperature by several degrees and putting a strain on your air conditioner. During the winter, warmer air trapped in the attic can condense under the roof, causing ice dams that can lead to serious roof damage.

Attic vents can be positioned in several ways. New homes built in the Midwest usually have a combination of continuous ridge and soffit vents.

Another option for controlling moisture is a energy recovery ventilator. Your builder can help you decide which method is best for your new home.