Today we are going to take a short tangent to explain one of the most common techniques out there for stopping Cold Air Penetration.
It seems as though virtually every building that is built goes up and then the entire structure is wrapped with “House Wrap.” Most of the time it appears as though the house all covered up with some sort of cloth – not quite!
The “White Cloth” that you see wrapping a new home has several trade names such as Tyvek and Typar. Those are brand names for House Wrap. We are thinking that most people really don’t know exactly what Tyvek does.
House Wrap is a fascinating product that performs excellently! It is a weather resistant barrier for the entire building.
- House wrap prevents rain and water from penetrating into the exterior wall cavity.
- House wrap also provides a wind barrier
- Both the wind and water barriers are things coming from outside towards the inside and both are very important!
House wrap also works the other way:
- House wrap allows moisture, a.k.a. water, to pass right through it but as it is going from the inside of the house to the outside.
- Think about that, it allows moisture to move through it but in only one direction. This is very important!
If rain were allowed to penetrate into the exterior wall cavity it could “feed” mold and mildew both of which could lead to lumber rotting. So, if House Wrap stops water from Penetrating the building envelope and at the same time allows interior moisture to escape it is almost a Miracle Fabric.
Truthfully, house wrap is one of the most ingenious building products to enter the market in a very long time. There are several types of House Wrap. More tomorrow.
Today’s photograph is of a Vermont Modular home in the midst of being ever so gently on its permanent foundation. Look carefully and “yours truly” is there.