Air sealing: the cheap work that does the heavy lifting

A house is a stack of holes wearing drywall. Warm air rises out the top, sucks humid outdoor air in at the bottom, and your HVAC pays for the round trip. In Charlotte that infiltration also drags moisture in, which is why sealing often improves comfort more than any amount of added insulation.

Where Carolina houses leak

• Recessed can lights punched through the ceiling, especially pre-2004 fixtures.
• The gap where drywall meets top plates along interior walls.
• Duct chases and plumbing stacks that run from crawl space to attic like a chimney.
• Attic hatches with no gasket and no insulation on the lid.
• Band joists down at the crawl space, which almost nobody ever seals.

What good sealing work looks like

A crew that takes this seriously shows up with foam guns, caulk, and rigid blocking, not just a blower truck. They work the attic floor before any insulation goes in, gasket the hatch, and box over the can lights with fire-rated covers. Two people can seal a typical attic in half a day, and the material cost is trivial next to the labor.

If you only do one thing after reading this site, get the attic floor sealed before topping up insulation. Doing it in the other order buries the leaks under a foot of fluff and roughly doubles the cost of fixing them later.

Next: choosing attic insulation or dealing with the crawl space.