Can the building envelope be too tight?

By Dani Sheehan. 

As we improve building materials and technology to make systems more efficient, we also need to consider the importance of proper ventilation as the unsung part of a quality roof. 

Did you know that there are certain holes in the roof that are necessary for the system’s ventilation? In a recent episode of Roofing Road Trips®, Heidi J. Ellsworth catches up with Mark Huysken of Quarrix Building Products to discuss the importance of a balanced ventilation system. He helps explain when existing structures can be retrofitted to achieve balance and the crucial role ventilation plays in ensuring a quality roof. 

Ventilation has always been an important part of the roofing system, but there’s been a growing awareness of the vital role it plays more recently. One of the reasons for this, Mark says, “I think a big part of it is the building envelope is getting tighter and tighter, and that’s not a bad thing. It’s a good thing to seal up houses better. But what’s happened when we’re sealing up the walls, and suddenly the exterior products are screaming for help because there used to be breathing through the walls and breathing through the roof deck [that is no longer there].” 

While these tight envelopes are great for some efficiencies, the roofing industry has realized that the walls and attics need to breathe and it’s catching up to everyone. As Mark explains, shingle prices have increased three times or more since he entered the industry, so if a roof must be replaced prematurely due to ventilation issues, it’s much more expensive than before. He continues, “As we seal up that house tighter, we’re also holding in moisture. And that moisture in the attic is bad. You’re going to see mold growth, your insulation in the attic will depress, get wet and damp and it’s not just going to ventilate improperly. It can be unhealthy to us as residents of the home.” 

Unfortunately, many contractors are not properly trained in the importance of ventilation or how to ensure it is balanced in the roofing system. There are now several training courses offered across the industry to help contractors looking to learn more about ventilation. Knowing what questions to ask your manufacturer can lead to great conversations and improve your assessment of each new project.  

Read the transcript or Listen to the podcast to hear some common mistakes when understanding ventilation and how to achieve a quality roof through a balanced ventilation system.