When should you replace attic insulation?
Short answer. Replace attic insulation when it has been soaked by a roof leak, contaminated by rodents or mold, badly compressed, or is so thin it cannot reach a useful R-value; otherwise, it is usually better to add new insulation on top. Insulation that is dry, clean and fluffy can stay, and air sealing the attic floor first gives the biggest payoff.
Signs it needs to come out
- Water damage: matted, stained or moldy insulation under a former leak. Wet cellulose clumps and loses much of its value.
- Rodent contamination: droppings, urine, tunnels and nests from squirrels or rats, common in Georgia attics near trees.
- Smoke or fire damage.
- Severe compression from stored items or foot traffic.
Signs it just needs topping up
- Depth below the tops of the ceiling joists.
- Uneven coverage with bare spots.
- An older home with only a few inches.
Vermiculite caution
Loose, pebble-like insulation that is gray brown or gold may be vermiculite, some of which contained asbestos. Do not disturb it. The EPA advises leaving it alone and hiring a trained professional if it must be removed.
Timing with roof work
Fix roof leaks before replacing insulation. If a roof replacement is coming, do it first, then remove damaged insulation, air seal, install baffles at the eaves and add new insulation. That order keeps the new material dry and the vents open. When insulation comes out, it is also the easiest moment to seal top plates and wiring holes that are normally buried. Read common causes of roof leaks and attic heat and shingles.