Recently, our vice president Candace was asked to take a look at a property and give a quote for insulation. Our sales staff usually videotapes their meetings with clients to help them decide on the best insulation for the job. We wanted to share this video to show you the importance of vapor barriers and ventilation.
Thermal Bridging and Condensation
In the first part of this video, you will see water droplets dripping off the nails that are poking through. Because the nails were put in from the outside on the north facing part of the house where there is not a lot of sunlight, there is thermal bridging. Consequently, any moisture that comes in is hitting the wood and making it wet. But the nails are where the water is condensing. As the water runs down the wall and gets closer to the floor, you can see that there is frost in the soffit. Because heat rises, the soffit is much colder.
Add a Vapor Barrier
Adding ventilation can temporarily solve this problem, but then heat and moisture would be pulled from the house even faster. And, losing heat is not energy-efficient. What should happen is a vapor barrier should be created at the thermal envelope to prevent the moisture from ever getting into the space. The other alternative is to spray foam the roof so the surface of the roof is protected by the foam. And because of its R-value, the surface of the foam will never be cold enough for the moisture to reach a dew point and condense.
At 38 seconds, you will see that on the other side of the house, there is an identical eve space that is significantly warmer. In fact, it is 20 to 30 degrees warmer, and there is no moisture. Consequently, the nail heads don’t show any rust. This is a good example of why vapor barriers and ventilation are important.
Insulation Is Key
Our recent blog about Rockwool insulation being designed for use as exterior continuous insulation is a great read. It will help you understand the importance of vapor barriers and ventilation.
If you have questions about our products, check out the FAQ section of our website. You may find your answers there. If not, contact us!
Watch the video on our YouTube Channel!
