Judd Haag is Vice President of Operations at Bone Dry Roofing and an Owens Corning Roofing Platinum Contractor. With headquarters in Indianapolis, Bone Dry serves 10 markets across the Central United States. Below, Haag speaks about the role ventilation plays in supporting a roof’s performance and occupants’ comfort.
Q: Is ventilation a bigger issue in certain parts of the country?
A: Ventilation presents different challenges depending on the climate. In hotter climates such as Texas, Florida, and Georgia, excessive heat in attics during the summer can bake shingles from the underside if not properly vented. In the North, ice dams and water infiltration are common problems that can occur due to unbalanced ventilation and inadequate insulation levels. Whether heat, humidity or cold temperatures, different regions battle different challenges, but ventilation is a common concern.
Q: As we head into winter, how does snow contribute to ice damming and lead to other problems?
A: As long as it stays cold inside the attic and the snow stays frozen on the roof, there typically is no issue. But insufficient insulation in the attic can allow heat from the home’s living area to rise up and move into the attic. If there is not enough ventilation to move heat out of the attic and replace the displaced attic air with cool air, heat will build up, causing the snow/ice on the roof to melt. As the water travels down the roof’s slope, it will refreeze above the gutter line. Meanwhile, as the warm attic air isn’t being replaced with cool air, the snow and ice up higher on the roof continues to melt. As this water flows down, it hits refrozen ice and creates a dam. The water now has nowhere to go except back underneath the shingles and down inside the living space.
Q: What visible signs on a home may suggest ice damming problems?
A: Unfortunately, it’s hard to see this type of damage without the roof being torn off. A roof replacement may turn up rotted decking close to the gutters, showing ice damming has occurred. This can be an unwelcome surprise to the homeowner. We alert the homeowner of this possibility, letting them know that some wood decking may need to be replaced based on what conditions reveal when the work gets underway. Depending on the pitch of the attic, it may be possible to see rotted decking inside from inside the attic space. Ice damming damage may show up as water stains or bubbling paint and drywall on a home’s interior. Rusted nail heads in the attic can also be a sign of improper ventilation as trapped moisture condensates, rusting and corroding the nail heads.
Q: What are some best practices for informing adequate insulation levels to support ventilation?
A: First things first, you have to get inside the attic space and see the conditions. If you turn off your flashlight, you should be able to see daylight infiltrating near the soffit intake ventilation. If you don’t see daylight, chances are good that the intake ventilation is clogged. Getting inside the attic is just as important as the exterior inspection, as 50 percent of the roof is in the attic. We tell customers that chances are, if we look only at the top side of the roof, we’ll be coming back later to address other issues. Proper installation of ventilation materials is also essential.
Tools can help inform the proper amount of insulation material depending on the dimensions of the space and the type of vent the contractor wants to install. The Owens Corning ventilation calculator will tell you how much intake you need and how much exhaust ventilation. You can do the long math, but technology and online calculators make it convenient and easy to size the material to products preferred for the job.
Q: Are there any tips contractors can offer homeowners to prevent moisture problems in the house?
A: It’s important to make sure the moisture stays in the living space or gets recycled by the home’s HVAC system. Bath fans are always good to install. Homeowners should ask their contractor to verify the bath fans are ventilated to the home’s exterior. Equipment such as humidifiers can make moisture management a challenge — especially when the humidity is cranked up at full capacity. Homeowners often say their health care provider suggested they add humidity to their environment. Moisture might be good for the human body, but it’s not so good for the house if there is no way to get it out.
Q: What’s one final piece of advice when it comes to ventilation?
A: It’s not just about exhaust ventilation. We’re seeing a lot more use of the ridge vent. But if the installer does not balance the ventilation system with the intake, the ridge vent can create a negative pressure in the attic. Air can be drawn from the living space into the attic creating even more issues than were there previously. People like the ridge vents for its aesthetic and it can give more ventilation than a box vent on most roof styles. But if you don’t add intake at the roof line, it creates too much exhaust which creates a negative pressure from inside the house and reduces the pressure equilibrium.