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Grizzly Insulation Co

Englewood Insulation  ›  Attic Air Sealing

Attic Air Sealing in Englewood, CO

Houses from the coal era were built to leak on purpose. We close the chases, chimneys, and wall-tops that made sense in 1925 and cost you money in every winter since.

Your local crew, minutes away

Commerce City HQ · both Englewood ZIPs

Where does a 1920s house leak from?

Old-house leakage is structural, not accidental. Here’s what drives it in the Englewood homes we audit:

Open balloon-frame wall tops, the big one
Chimney & flue chases, oversized by design
Plaster cracks & ceiling fixture cuts
Original hatches, stair-tops & abandoned vents
TRUSTED PRODUCTS & PARTNERS

The Brands Behind Every Grizzly Install

We don’t install mystery material. Every Arvada project uses products from the industry’s most trusted manufacturers.

01THE PROBLEM

Balloon Framing Turned Every Wall Into a Flue.

Pre-1930 framing left wall cavities open from the cellar to the attic, so heated air rides your walls upward day and night, the stack effect with a dedicated lane. Capping those cavities from the attic is the highest-value hour of work an Englewood bungalow can buy.

AWall tops open to the attic sky

Look down a bungalow’s wall cavity from the attic and you can see cellar light. Every one of those open tops leaks like a chimney, we block and foam them all, the fix these houses have waited a century for.

BChimneys carrying more than smoke

Masonry chimneys run through framed openings sized generously in 1925. Warm air pours up the gap between brick and framing, we close it with metal flashing and fire-rated sealant, clearances respected, never bare foam on a flue.

CA century of ceiling surgery

Gas conversions, electrical retrofits, bathroom fans, every decade cut new holes toward the attic and sealed none. The plaster around each cut cracks with age, multiplying paths upward.

DHatches from the ladder-and-push era

Original attic hatches are a board in a hole, no gasket, no insulation, no latch. Rebuilding one takes an hour and outperforms almost any other sixty minutes spent on an old house.

02THE FIX

Seal the Era Out. Keep the House Original.

Standalone sealing sharpens a bungalow immediately; sealing before insulation multiplies the whole project. The audit tells you which your house needs:

 Sealing OnlyThe immediate draft fixSeal + InsulateThe century-home reset
How it worksBalloon chases blocked, chimney flashed, fixtures capped, hatch rebuiltAll sealing first, then cellulose from near-zero to R-49–R-60
Best forHomes with tolerable insulation but constant draftsThe classic Englewood bungalow: leaky and bare
Install time Half a day, most homesOne day, both layers
Cost per R-value The cheapest comfort per dollarBigger ticket, compounding return
Air sealing It IS the job, fire-safe throughout Always sequenced before depth
Pest deterrence Closes wall-void rodent lanes, Borate cellulose optional above
Eco profile No material added, Recycled cellulose on top
Our verdict: worthwhile in every pre-war Englewood home, even before insulation.
When the pair wins: a bare bungalow attic deserves both steps in one visit. See attic insulation in Englewood.
03WHAT TO EXPECT

A Morning in the Attic, a Century of Gaps Closed.

The sequence of an Englewood sealing visit:

STEP 1 · PREP
Cavity-by-cavity survey

Every wall top, chase, and fixture gets located and logged from the attic side. Balloon-frame homes get their full cavity map before anything is sealed.

STEP 2 · REMOVAL
Old fill lifted at each target

Whatever thin material exists gets moved aside at each leak point and returned after, nothing leaves unless it is contaminated.

STEP 3 · AIR SEALING
Block, foam, flash

Rigid blocking caps each open wall cavity before foam locks it; the chimney gap gets metal flashing with fire-rated sealant; fixtures get airtight covers.

STEP 4 · INSTALLATION
The hatch becomes an asset

Gasket, rigid insulation, and a positive latch turn the original board-in-a-hole into the tightest square foot of the ceiling.

STEP 5 · QUALITY CHECK
The ledger, photographed

Every capped cavity and sealed penetration goes into a photo ledger for your records, proof of exactly what a century left open and we closed.

The Grizzly 100% Guarantee

If the work isn't right, we make it right. That's the reputation we've built across the Front Range, and it's our only sales pitch.

04COST & SAVINGS

What Air Sealing Costs in Englewood

The best return-per-dollar work an old house can buy. Four price drivers, itemized after a free audit.

Cavity count

How many balloon-frame wall tops need capping

Chimney work

Flashing and fire-rated detailing at masonry

Ceiling condition

Plaster crack networks and fixture cuts

Hatch rebuild

Gasket-and-latch or full insulated rebuild

Three ways the net cost drops

Xcel Energy rebates

Air sealing is a rebated measure in Xcel territory, and pre-war homes post the biggest measured gains.

Federal 25C tax credit

30% of qualifying insulation costs, up to $1,200 per year, under the Inflation Reduction Act.

Radiators finally win

Stop feeding the stack effect and the heat your system makes actually stays on the floor it was made for.

★ ★ ★ ★ ★

"You could feel air moving up the walls of our 1921 four-square by the medical district. They capped nineteen open cavities and flashed the chimney gap in one morning. The ground floor stopped being the cold floor."

F
Frank O.

Homeowner · Medical District, Englewood · Attic Air Sealing

05QUESTIONS

Air Sealing in Englewood, Answered Straight

Prefer to just ask?

Call and talk to the crew that will actually be in your attic.

They were engineered that way. Coal heat needed draft, so balloon framing left wall cavities open top to bottom and chases ran generous. Modern furnaces inherit that ventilation as pure loss. Sealing retrofits the 1920s logic without touching the character.

It is modest work with outsized returns: priced by cavity count, chimney detailing, ceiling condition, and hatch scope. Pre-war homes have more to seal than newer ones, and correspondingly more to gain. The audit produces a written, itemized number.

It is the pre-1930 method where wall studs run unbroken from foundation to roof, leaving cavities open the full height of the house. Those cavities behave like flues, pulling heated air upward constantly. Capping them at the attic is the defining air-sealing move in Englewood’s housing stock.

Only with the right materials, which is the point of hiring it done. Combustion clearances get respected with metal flashing and fire-rated sealant; expanding foam never touches a flue on our jobs. Fire-safe detailing is where old-house sealing earns its keep.

Most Englewood homes seal in half a day; four-squares and homes with heavy chase work can run a full day. It is quiet attic work, you stay home, nothing in the living space is disturbed.

Not from ceiling sealing, these homes leak generously everywhere else. We are closing the most expensive leaks, not hermetically sealing the house. Ventilation stays healthy; only the heat-theft stops.

07GET STARTED

Retire the Coal-Era Draft Plan.

Free audit with a mapped list of every open cavity and chase. Fire-safe sealing, photographed proof, done in a morning.

Get Your Free Draft Audit

Takes 30 seconds. We reply within 24 hours.