El Cid cottage
1,000 sq ft · 3 in fiberglass · add 12.6 in fiberglass
$1,250–$2,000Now R-7 → R-38
West Palm Beach · planning ranges
Blown-in insulation cost in West Palm Beach.
Most attic top-ups land between $1,500 and $4,000. The spread is square footage, how much is already there, and whether the old fill has to come out.
Same math as the planner
Cardinal has published a worked attic: 1,800 square feet, four inches of settled fiberglass, about an R-9, and a planning range of $2,100 to $3,350 to reach R-38 with blown fiberglass. The rows below use that band. Change the house and the range scales. None of these are bids.
Flamingo Park bungalow
1,500 sq ft · 4 in fiberglass · add 11.7 in fiberglass
$1,750–$2,800Now R-9 → R-38
Published 1,800 sq ft example
1,800 sq ft · 4 in fiberglass · add 11.7 in fiberglass
$2,100–$3,350Now R-9 → R-38
33415 ranch
2,200 sq ft · 2 in fiberglass · add 13.4 in fiberglass
$2,950–$4,750Now R-4 → R-38
Open attic, cellulose
1,800 sq ft · 0 in bare · add 10.9 in cellulose
$2,750–$4,400Now R-0 → R-38
What moves the number
Attic floor, not living area
A two-story in El Cid can have a small upstairs footprint. Price the floor you can stand on, not the tax record.
Depth you already have
Four inches of settled fiberglass is not halfway to R-38. It is about a quarter of the way. The planner shows the gap.
Removal
Wet fill, a roof leak, or rodent damage means the old material comes out first. That is extra labor, often $1.25 to $2 a square foot on top of the blow.
Access
A closet hatch in Old Northwood takes longer than a walk-in attic in 33415. Knee walls are a different assembly, not a hose-and-go.
Baffles and dams
Every open soffit needs a baffle. Every flue and non-IC can needs a dam. Those are in a normal job. A house with none of them takes more time.
Material
Cellulose hits R-38 in fewer inches. The dollar range here follows the R-value you still need, not a trick that makes one bag look cheaper.