I recently wrote a blog post titled Building Science-Building Shell Layers-Vapor Control Layer. This blog is going to expand on that discussion with information on several choices of vapor retarders. Continue reading “Construction Materials-Vapor Retarders”
Building Science-Building Shell Layers-Thermal Control Layer
Last week we talked about interior moisture drive through the building shell, the vapor control layer. This week we will continue with the building shell layers discussion, number 4 on our list is the thermal barrier. Continue reading “Building Science-Building Shell Layers-Thermal Control Layer”
Building Science – Building Shell Layers – Vapor control layer
Last week we talked about the what makes a house “tight”, the air control layer. This week we will continue with the building shell layers discussion, number 3 on our list is the vapor control layer or vapor retarder.
Continue reading “Building Science – Building Shell Layers – Vapor control layer”
Building Science-Building Shell Layers-Air Control Layer
Last week we talked about the outer most layer in a building, the rain control layer. This week, we will continue with the building shell layers discussion. The air control layer is next on the list. Continue reading “Building Science-Building Shell Layers-Air Control Layer”
Building Science-Building Shell Layers-Rain Control Layer
The next four blog postings are all going to discuss a few of the most important parts of a building, the four layers in a building shell. I’m leaving out the “structural layer”, though it’s the most important part of a house, the other layers are less understood. Continue reading “Building Science-Building Shell Layers-Rain Control Layer”
Building Science-Passing a Blower Door Test
In my last blog, I talked about vapor diffusion and the perm rating. Sometimes it is better to eliminate the polyethylene sheeting most builders in Minnesota are using for both the air and vapor barrier. The problem then becomes passing the blower door test. Continue reading “Building Science-Passing a Blower Door Test”
Building Science-Perm
Builders in northern Minnesota have been using polyethylene sheeting on the warm in winter side of wall assemblies for years. Beginning in the 1960’s, we were taught that the poly would stop vapor diffusion in building cavity, keeping walls dryer. During the 1990’s and 2000’s, building scientists determined that only a small percentage of wall wetness comes from vapor diffusion. So, how does moisture end up inside building assemblies in a northern climate? Mostly by air leaks! Continue reading “Building Science-Perm”
Building Science-R-value
In our northern climate, how quickly a structure loses heat is dependent on three factors, the first is transmission heat loss which includes the difference between inside and outside temperatures, called the delta T, and the resistance to heat flow, or R-value of the building assemblies. Continue reading “Building Science-R-value”
Building Science-Humidity
What is humidity? According to Wikipedia, humidity is the amount of water vapor in the air. A nice, simple explanation that all of us can understand. Now look at the chart below. Continue reading “Building Science-Humidity”
Building Science-“Breathe”
In this blog, I’m going to discuss building tightness and the code dealing with air leakage. The 2012 International Residential Code for One and Two-Family Dwellings is the current code in force for the state of Minnesota at the time of this blog. Chapter 11 deals with energy conservation, what most in the building industry call the energy code. The code on building air leakage states: Continue reading “Building Science-“Breathe””