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Insulation · Drill & fill

Add insulation to suitable finished walls without opening every cavity.

Drill-and-fill is a retrofit method for adding blown insulation to accessible finished wall cavities. The crew plans an access pattern, opens each eligible cavity, installs material to the specified density, and closes the access points according to the agreed finish scope.

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  • Two planned access openings per cavity: halfway up and at the top
  • Blown fiber, installed cavity by cavity
  • Studs behind the finished wall
Where
Suitable finished walls in existing buildings
Access
Two planned openings per cavity, halfway up and at the top
Material
Blown fiberglass
Finish
Openings closed under the agreed finish scope

What it is

Many older walls were built with empty or underfilled cavities. Drill-and-fill reaches those cavities from one side of the finished wall, through two openings in each one, halfway up and at the top, and blows insulation in until the cavity is filled to the specified density.

The access side, the siding or interior finish, and how the openings are closed are agreed before the work starts, so it is clear what the finished wall will look like and what, if anything, falls to another trade.

Where it can fit

  • Older exterior walls with empty or underfilled cavities
  • Finished spaces where full demolition is undesirable
  • Some garages and additions

Not every wall qualifies. Some siding types, masonry walls, knob-and-tube wiring, wet walls, and inaccessible cavities can rule the method out; the inspection decides.

How it is installed

  1. Inspect the wall

    Inspect wall construction, access side, siding or finish condition, known utilities, and moisture concerns.

  2. Confirm it qualifies

    Confirm that the cavity and exterior system are appropriate for the method.

  3. Open and fill

    Make the planned openings, halfway up and at the top of each cavity, and install material cavity by cavity.

  4. Verify and close

    Verify coverage and close the openings under the documented scope.

Built to the assembly. Installed for local inspection.

Thermal Shop works from the approved plans, the selected product documentation and the requirements adopted for the project's jurisdiction. We document installed depth or assembly details and coordinate questions before finishes cover the work.

BIBS

Fiberglass blown behind fabric so open cavities fill around wiring, plumbing and framing details.

See How BIBS Works

Attic insulation

Loose-fill fiberglass or cellulose installed to a specified depth across a prepared attic floor.

Compare Attic Options

Homeowner attic upgrades

From a clean top-off to removal, air sealing and re-blow, the scope begins with existing conditions.

Compare Attic Upgrade Paths

Start your insulation project

Homeowners

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How it works
  1. Request a free estimate and tell us what you're working on and where.
  2. We look at the attic, the house, or the concern first, then recommend the material and give you options.
  3. We install the work you approve and clear the work area when the install is done.

Contractors

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How it works
  1. Request a bid with your plans, specs, and the work you want priced.
  2. Insulation is priced on its own bid, separate from gutters and shelving.
  3. We schedule around site readiness and inspections, and clean up the work area when the install is done.