Wrap it up! Going beyond traditional moisture wraps

This piece is taken from our newsletter "Force of Nature" see more and subscribe here.

When builders and architects talk about "wrapping" a house they usually mean thin films of different materials that act as moisture and sometimes air barriers.Think "Tyvek" wrap.  But builders can and do go much bigger with wrapping. 

For example here at the Fourth Pig we renovated a 1960's leaky cottage, including wrapping the outside with straw bales (see photo above), resulting in a Passive House retro standard air tightness. Adding straw bales to existing walls (really thick walls) generally has to happen in a rural community where you have land to build out onto without shrinking floor space, but you can get a much more energy efficient building this way. 

PassiveHouse builders doing retrofits will "wrap" houses - layering insulation and other materials to the outside of an existing wall and then add cladding to the exterior of a building (for one example see here). Some PassiveHouse structures have been built inside old buildings.

Perhaps it is cheating to call it a "wrap" but one of the more interesting approaches is a couple in Sweden who took an existing house and built a greenhouse around it. With a little bit of sun they can get a very large heating boost, even in the winter. The ultimate in passive solar? The glass is safety glass and has doors/windows/vents to help control the heat. 

The whole notion of "inside/outside" is challenged a bit - as it can be raining/snowing but they are "outside" of their house on the deck or roof area all dry. The owners did not seem to do any serious insulation of the existing home they put in a greenhouse, so they do have some colder spots and areas, but they are growing plants (that in Sweden require a greenhouse) and built a natural water/sewage system. 

Get a tour of this house wrapped in glass in this video: