Everyone talks about R-value, but two of the most important parts of a great attic job have nothing to do with how much insulation you add. They're air sealing and ventilation baffles — and skipping them is why a lot of "new" insulation underperforms.
Insulation slows heat. Air sealing stops air.
Insulation resists heat transfer, but it does almost nothing to stop air from leaking through the gaps around can lights, top plates, plumbing stacks, and your attic hatch. If those leaks are open, your conditioned air escapes right past the insulation. Air sealing closes them first.
Baffles let your attic breathe
Your attic needs airflow — in through the soffit vents at the eaves, up the roof deck, and out the ridge. When insulation gets pushed into the eaves, it blocks that intake. Ventilation baffles (rafter vents) keep a clear channel so air can flow the way it's supposed to.
- Keeps the roof deck dry and prevents mold and rot
- Reduces the risk of ice dams in winter
- Helps your insulation perform to its rating
Why removal is the perfect time
Both of these are far easier to do when the attic is empty. That's why a removal and replace is the ideal moment to air seal the ceiling and add baffles — the deck is exposed and we can reach every gap.
Add insulation without sealing and ventilating, and you're just putting a thicker blanket over the same leaks.
It's the unglamorous part of the job, but it's the difference between insulation that looks good and insulation that actually lowers your bill. Questions? We're happy to explain it in person.