Blown-In Insulation Miami

Blown-in loose-fill insulation is the most practical and cost-effective solution for bringing an existing Miami home's attic to current code insulation levels. Unlike fiberglass batts (which require accessible, unobstructed joist bays and leave gaps around obstacles), blown-in material covers the entire attic floor uniformly, fills gaps around joists, penetrations, and blocking, and can be added to any depth without structural modifications. A two-person crew with a truck-mounted blower can insulate a typical Miami home's attic floor in 3–4 hours.

We use two primary materials for blown-in attic insulation. Blown-in fiberglass (loosely packed, low-density fiber) has an R-value of approximately 2.5 per inch, settles slightly over time, and is well-suited for Miami's dry attic conditions (not appropriate for wet areas). Blown-in cellulose (recycled newspaper treated with borate fire retardant) has an R-value of approximately 3.7 per inch, is more resistant to air movement through the insulation layer, and is slightly heavier. Both materials are appropriate for Miami attics — we recommend based on the existing insulation type, joist depth, and whether any moisture has been present.

A critical step before any blown-in installation is attic air sealing. We identify and seal the major air bypass pathways — can light housing penetrations, top plate gaps, pull-down stair perimeters, and AC duct penetrations — before blowing insulation. An unsealed attic with R-30 blown-in performs much worse than a sealed attic with R-22, because air bypasses are far more thermally significant than the average R-value suggests. We don't cut this step.