The Building Envelope

 

Years ago energy and material were a lot less expensive than they are now. Then when people started insulating their homes a whole new set of practices had to be developed. Tighter building envelopes caused indoor air problems, humidity problems and in the worst case, rotten wood from moisture condensation. Material off-gassing from paints, carpets and plywoods caused respiratory problems and increased allergic reactions. In some cases indoor air quality became as bad as the smoggiest day in Los Angeles! Those were the bad old days.

Now there is greater awareness of the need for mechanical ventilation. Greater emphasis on air sealing techniques, vapor barriers and rain screens not only lowers your energy bills but provides clean air, controlled humidity and prolongs the life of your structure.

Now there are a lot more choices in insulation. Fiberglass, cellulose, dense pak cellulose (dry and wet sprayed), open and closed cell spray foam, various types of rigid insulation, etc. can all be used depending on the situation. Knowing when and where and how much takes knowledge and experience. Balancing heat loss, solar gain, thermal mass, fenestration and insulation has come a long way.