USI Blog

How the Structure of a Building Affects the Flow of Heat, Air and Moisture

HomeWhen homeowners think about the buildup of heat, air and moisture in their home, they don’t typically think of the structure of their home first. However, the structure of a building plays a huge role in the flow of these elements. By understanding how this affects flow, you can take active measures to prevent damage to your home.


The driving force behind airflow is wind. The structure of your home determines which kind of pressure is placed on the leading edge or side of your home that is hit with the airflow. Low-slope roofs create more of a negative pressure or uplift on the leading edge of your structure. Homes with a 25-degree slope or more have a positive pressure on the leading edge, creating less uplift.


Naturally, heat flows upward in a home, which is why your attic is always warmer than your basement. Once again, the structure of your building affects the flow of heat to the top of it, which is referred to as stack pressure. The higher your home or building, the higher the stack pressure at the top. Homes often offset this pressure with exhaust and HVAC fans. While exhaust fans move heat outside the building to offset the pressure, HVAC fans stabilize pressure from within.


The flow of moisture into a home from outside is a top concern. When moisture gets into the house easily, it can cause problems with the structural integrity of your home by warping wood. Thankfully, insulation with a vapor barrier can help protect your structure by preventing moisture from entering your home. If moisture gets passed the first vapor barrier, it will become trapped between the two barriers and ruin your insulation.

Learn More

For more information on about the structure of your building or to learn more about insulation, contact USI online to find a branch near you and get a free quote. USI believes in excellence in every step of the process and ensures timely completion and quality of service, time after time.