Maryland Attic Air Sealing Services
The Missing Step That Makes Insulation Work
Many homeowners believe that adding more insulation is the only way to lower energy bills, but that is only half the battle.
Think of fiberglass or cellulose insulation like a wool sweater. It keeps you warm, but if a cold wind blows, the air cuts right through it. You need a windbreaker to stop that airflow.
Air Sealing is that windbreaker.
In your attic, hundreds of small gaps (around wires, pipes, and wall tops) allow your expensive heated air to leak out and escape through the roof. We find these hidden leaks and seal them permanently with expanding foam.
The Result: Your insulation performs better, your rooms stay comfortable, and your HVAC system doesn’t have to run as often.
Signs I Need Attic Air Sealing
- Non-Stop HVAC: Your furnace seems to run constantly but never quite reaches the comfortable temperature you want.
- Mystery Drafts: You feel cold air movement near electrical outlets, light switches, or baseboards.
- High Energy Bills: Your BGE or PEPCO bills are significantly higher than your neighbors’ or spike unpredictably. High BGE or PEPCO bills during the winter.
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The “Icicle” Warning: If you see icicles or “ice dams” forming on your gutters, it’s not just a gutter problem. It means expensive heated air is escaping through your attic floor, melting the snow on your roof, and freezing at the edge. Air sealing stops this cycle.
See how we sealed this attic in Columbia, MD!
The 5 Biggest Air Leaks in Maryland Homes
- Recessed Lights (The “Chimney” Effect)
Old-style “can lights” often have large vents in the housing. They act like mini-chimneys, sucking your paid-for heat right into the attic. - Top Plates
This is the top of your interior walls. In most homes, there is a gap where the drywall meets the wood framing in the attic. It looks small, but added together, it’s like having a window open all winter. - Bathroom Fans
If your fan isn’t sealed to the drywall, it pulls moist, warm air from your bathroom into the cold attic—a major cause of mold. - Attic Hatches & Stairs
The entrance to your attic is often uninsulated and unsealed. Without a proper cover or weatherstripping, it leaks air constantly - Wire & Pipe Penetrations Every time an electrician or plumber drilled a hole to run a wire or pipe, they created a permanent air leak that needs to be sealed.
Our Professional Sealing Process
We Go Beyond “Great Stuff” Foam Effective air sealing requires more than just a can of foam from the hardware store. We use industrial-grade materials and BPI-standard techniques to permanently lock conditioned air inside your home.
- Fire Safety & Heat Shielding: Before we seal anything, we identify high-heat areas like chimney flues. We use fire-rated sheet metal and high-temperature caulking to seal these gaps while maintaining code-compliant clearances.
- Sealing the “Super Highways” (Chaseways): We identify large open cavities hidden in closets or behind walls. We cover these massive leaks with rigid foam board and seal the edges with two-part expanding foam to create an airtight lid.
- The Detail Work (Top Plates): This is the tedious work most contractors skip. We crawl to the edges of your attic to seal the top plates (where your walls meet the attic floor) and every wire penetration to ensure your ceiling is airtight.
- Hatch & Door Treatment: We install heavy-duty weatherstripping and insulation dams around your pull-down stairs or attic hatch to stop it from leaking like an open window.
How We Measure & Prove Results
We Don’t Guess—We Test.
Most insulation companies just add material and hope for the best. At Leonard Home Performance, we use building science to verify our work.
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The Baseline: Before we start, we perform a Blower Door Test as part of your Energy Audit to measure exactly how much air is leaking out of your home.
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The Verification: After the air sealing is complete, we run the test again. You will see a concrete difference in the numbers, proving that the drafts are gone and your home is tighter.
Thermal Imaging:
We also use infrared cameras to visually confirm that the cold spots in your ceiling have disappeared. You get a report showing exactly how much we improved your home’s efficiency—often reducing leakage by 20–30%.
Air sealing should come before insulation. Once loose-fill or batts are installed, it’s harder to access the attic floor and properly seal gaps and penetrations.
Air sealing usually reduces moisture problems because it limits humid air leaking into cold attic spaces. If the home becomes very tight, we may recommend controlled ventilation (like bath fan improvements or whole-home ventilation) based on testing and conditions.
Most homes benefit from soffit baffles to keep insulation from blocking intake vents and to maintain airflow from soffit to ridge/roof vents. Baffles are installed before adding insulation. Air sealing targets leaks at the attic floor and typically does not reduce attic ventilation when vents are properly maintained.
Most attic air sealing jobs take half a day to a full day, depending on attic size, accessibility, and the number of bypasses to seal.
The BGE and PEPCO audit typically includes an attic inspection, identifying major air leaks (“bypasses”), and performance testing like a blower door test (and thermal imaging when conditions allow). You’ll get prioritized recommendations and rebate-eligible options.
We perform attic air sealing for homeowners in Maryland within the BGE and Pepco service territories—especially in and around Baltimore City/County, Towson, Columbia, and nearby areas.
Yes—Leonard Home Performance is licensed (MHIC #165469) and insured (COI available upon request). We’re Building Performance Institute certified to perform home energy audits and weatherization work.
Ready to Fix Your Drafty Home
Don’t let another month of heating bills go to waste. Call 443-690-8233 or click below to schedule your BPI Energy Audit and secure rebates of up to $15,000.