As an Amazon Associate I earn from qualifying purchases.
R-49 is the common target for the roof or ceiling in cold and mixed climates. That is about 20 inches of blown fibreglass, 15 inches of blown cellulose, 16 inches of fibreglass batt or about 8 inches of closed-cell spray foam. Air seal the ceiling plane before adding any of it.
Old insulation that's wet, rodent-damaged or contaminated has to come out before new goes in. This prices both the DIY route and the contractor route.
With these inputs:
| Result | Value |
|---|---|
| Volume to remove | 800 cu ft |
| Disposal bags | 27 contractor bags |
| Contractor cost | $1,800 |
| DIY cost | $559 |
| Vacuum rental (2 days) | $320 |
| Landfill / disposal fee | $155 |
| Your estimate | $1,800 |
Volume = area × depth in feet · Bags = volume ÷ 30 cu ft per contractor bag · Contractor cost = area × rate, adjusted for depth and condition
No, if it's dry, clean and rodent-free — just add unfaced material on top. Remove it when it's wet, mouldy, contaminated with droppings, or you need access for air sealing.
Most jobs land between $1 and $2.25 per square foot, so a 1,200 sq ft attic is roughly $1,200 to $2,700. Rodent contamination and deep fill push it higher.
When it is wet, mould-affected, rodent-contaminated or fire-damaged, and when there is a reason to see the ceiling plane underneath — knob-and-tube wiring being the classic case. Dry, clean, settled insulation is almost always cheaper to top up than to remove and replace.
Treat it as a hazardous job. Old attic insulation holds decades of dust, rodent droppings and possibly vermiculite, which may contain asbestos and must not be disturbed by anyone not qualified to handle it. Respiratory protection is the minimum for ordinary material, and suspected vermiculite is a stop-work-and-test situation.
It scales with area, depth and how bad the access is, and contamination pushes it up sharply because the disposal route changes. Get quotes on your measured attic area and stated depth rather than the house's floor area, and ask specifically what disposal is included — that is where removal quotes most often differ from each other.
Need the whole roof at once? The free roofing calculator works out roof area, squares, shingle bundles, underlayment, drip edge, ridge cap and installed cost from one set of measurements.