Air Sealing | Portland, ME
Portland has Maine's most varied pre-war housing. West End Victorians built with balloon framing have unblocked wall cavities that act like chimneys, pulling heated air from basement to attic. Back Cove homes develop ice dams every January from attic air leakage. Triple-deckers on Munjoy Hill have complex air pathways connecting individual units. We air seal Portland homes every week and know exactly where the leaks hide in each era and style.
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Balloon-frame construction means wall cavities run unobstructed from the basement sill to the attic. Warm air rises through these cavities like a chimney. Dense-packing the walls and blocking the top plates stops the stack effect entirely.
Ice dams on Back Cove area homes trace back to warm air escaping through attic penetrations around wiring, plumbing stacks, and light fixtures. Sealing these bypasses eliminates ice dams at the source rather than treating the symptom.
Multi-unit buildings have air pathways that cross unit boundaries through shared walls, floors, and utility chases. We isolate each unit's thermal boundary and seal penetrations unit by unit, often coordinating with building owners or condo associations.
We use diagnostic testing to find every leak, not just the obvious ones.
We depressurize your home with a calibrated fan to measure baseline air leakage and identify exactly where conditioned air escapes. Works in every Portland housing type from Victorian to postwar Cape.
Our crew works through every penetration, bypass, and gap, using foam, caulk, and weatherstripping as appropriate. For balloon-frame homes we block wall cavities at the top plates. For triple-deckers we seal unit boundaries at floors and shared walls.
We run a second blower door test after sealing to measure the improvement and confirm we've hit the target. You receive a before-and-after reading on paper.
"I had cold corners in my West End Victorian for years. After Horizon sealed the attic bypasses and blocked the wall cavities, the chimney effect disappeared completely. The difference was immediate."
"Our Back Cove Cape had ice dams every winter. Horizon sealed the attic bypasses and combined it with insulation. No ice dams this past January. The house holds temperature completely differently now."
"Very detail oriented, extremely knowledgeable, and easy to work with. Cody explained everything they were sealing and why. Heating bills dropped right away."
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