We’ve talked a lot about the benefits of air sealing your Katahdin Cedar Log Home. Because there are multiple joinery opportunities for small air leaks in a log structure, our dealers and builders take meticulous care in sealing each intersection for a good seal. A new air sealing system called AeroBarrier is a one-step way to ensure air tightness to meet energy efficiency code requirements.
How Does AeroBarrier Work?
AeroBarrier uses similar technology the parent company AeroSeal used for sealing ductwork using air pressure and aerosolized sealant to achieve a tight seal. We spoke with AeroBarrier dealer John Murphy, owner of Murphy’s Cell Tech (murpheyscelltech@gmail.com) in St. Johnsbury, Vt., about how the system works. His business has focused on air sealing homes both new and existing since 1978, and his company services New England, Eastern Pennsylvania and Eastern New York.
The focus is on reducing the air exchanges per hour (or aeh) values to low levels, which indicate the building envelope is well sealed against air incursion. Murphy explained that AeroBarrier applies specialized blower door equipment and a series of vaporizing spray guns to achieve air sealing. After covering and sealing openings such as windows, doors, vents and other appropriate air circulation areas, the blower door fan is turned on.
But here’s the key: in traditional blower door testing, the inside of the building is depressurized by the fan blowing air out of the building. Air leaks are identified by spotting differences in temperature using an infrared UV camera.
With AeroBarrier, the blower door is turned around and air is blown into the structure, raising inside air pressure. The aerosol sprayers are then activated to atomize the sealant to a size of about 10 microns. The pressurized air escapes the interior through the tiny gaps and cracks, carrying the sealant with it. Sealant gradually fills the holes, sealing the exterior envelope. The blower door fan equipment monitors the air exchange rate every 90 seconds. The AeroBarrier sealant is sprayed until the desired air exchange level is achieved.
How Will it Work in Katahdin Cedar Log Homes?
“Once the exterior of the home is closed in and insulation is applied to the inside walls is roughly the time frame to install AeroBarrier,” Murphy said. Any horizontal surfaces, such as floors, are masked. “The sealant vapor will not stick to ceilings or walls, as it is heavier than air,” he added. Once the blower door fan is stopped the vapor falls to the floor to be removed with the masking materials. The vapor itself is an opaque substance that doesn’t show where it’s been drawn into the gaps and cracks. Murphy said that AeroBarrier has been used on existing homes, including Arts and Crafts antiques and renovations for tight air sealing benefits reducing 9.3 aeh to an airtight 0.23 aeh. Once the sealing is completed with AeroBarrier, there’s no need for additional blower door tests, because the desired air exchange per hour threshold has been met as indicated by the blower door equipment.
This is exciting new technology to add to Katahdin Dealers’ arsenal to deliver your log home with high energy efficiency to save energy and money over the life of your new home.