Insulation Before & After Gallery in Union City | Topside Attic Insulation Union City

Insulation Before & After in Union City, CA

Photos don’t lie. A blower-door reading of 4,200 CFM50 dropping to 2,100 tells one story; the photo of compressed, rodent-compromised fiberglass getting replaced with properly installed blown-in cellulose tells another. Below are real jobs we’ve completed in Union City, from the Decoto District up to the newer builds near the BART station. Each entry shows what we found, what we did, and what the homeowner walked away with.

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Recent Transformations

Attic Insulation Removal & Replacement - Decoto District, 1960s Ranch

Original attic insulation in Decoto District home showing compressed fiberglass with visible gaps and discoloration — Before: Original fiberglass batts compressed to R-11 equivalent, with gaps at the eaves where conditioned air was escaping into the roof deck.

New blown-in cellulose insulation at proper depth with sealed top plates and air barriers — After: Sealed top plates and can-light penetrations, then blown-in cellulose to R-38. Blower door dropped from 3,800 CFM50 to 1,950.

The homeowner in the Decoto District called us after two winters of PG&E bills climbing past $340. We pulled back the existing fiberglass and found it compressed to maybe three inches in spots, with original 1960s top plates completely unsealed. We air-sealed every penetration, installed baffles at the eaves for proper ventilation, then blew GreenFiber cellulose to a consistent R-38. The blower-door test - a pressurization reading that shows, in one number, how much air your building envelope is losing - read 3,800 CFM50 when we arrived and 1,950 when we left. Written scope, written price, photo record. Done in one day.

Crawl Space Encapsulation & Vapor Barrier - Near Alvarado-Niles Road, 1970s Split-Level

Unencapsulated crawl space with exposed dirt floor and moisture damage to floor joists — Before: Dirt crawl space with standing water after rain, fiberglass batt insulation falling from joists, mold on subfloor.

Fully encapsulated crawl space with white vapor barrier, sealed vents, and conditioned air supply — After: 20-mil reinforced vapor barrier sealed to walls, closed-cell spray foam on rim joists, dehumidifier drain line to exterior.

This split-level near Alvarado-Niles Road had a classic Union City problem: clay-heavy soil that holds moisture against the foundation, plus original vented crawl space design that pulls humid summer air directly under the living floor. The fiberglass batts were sagging and black-spotted. We removed them, graded the soil, laid a 20-mil reinforced vapor barrier sealed to the walls with tape and mastic, then sprayed two inches of Demilec closed-cell foam on the rim joists. A small dehumidifier with a direct drain line keeps the space below 55% relative humidity year-round. No more musty smell rising through the floor registers.

Spray Foam Insulation - Newer Build Near Union City BART, 2005 Townhouse

Unfinished attic knee walls with fiberglass batts and visible air gaps in townhouse near BART station — Before: Fiberglass batts in kneewalls with no air barrier, allowing conditioned air to short-circuit into attic space behind.

Open-cell spray foam applied to kneewalls and roof deck creating conditioned attic space — After: Icynene open-cell spray foam on kneewalls and roof deck, converting attic to conditioned space. HVAC ductwork now inside the envelope.

The townhome cluster near the BART station was built with kneewall attics that are technically “inside” the house but functionally outside - fiberglass batts with no air barrier, so the master bedroom was roasting in summer and cold in winter. We sprayed Icynene open-cell foam on the kneewalls and roof deck, bringing the attic fully into the conditioned envelope. The HVAC ductwork, previously sitting in 140-degree summer attic air, now runs in 75-degree space. The homeowner’s summer cooling load dropped enough that their existing two-ton unit finally cycles properly instead of running flat-out.

Radiant Barrier Installation - Hillcrest Area, 1980s Two-Story

Dark roof deck absorbing heat with no reflective barrier in Hillcrest area attic — Before: Dark asphalt shingle roof deck radiating heat downward, attic temperature exceeding 145°F on summer afternoons.

Radiant barrier stapled to roof rafters reflecting heat with proper ventilation channels — After: Owens Corning radiant barrier properly stapled to rafters with two-inch ventilation channels, attic peak temp reduced 28°F.

The Hillcrest area gets afternoon sun straight off the bay with no marine layer buffer, and this two-story had a dark shingle roof that turned the attic into a radiator. We didn’t replace the existing insulation; instead we installed an Owens Corning radiant barrier on the rafters with proper two-inch ventilation channels so the roof deck can still dry. Attic peak temperature dropped from 147°F to 119°F on a 95-degree day. The upstairs bedrooms, previously unusable until 10 PM in July, now cool down by 7 PM. Sometimes the right fix isn’t more insulation; it’s stopping the heat before it gets in.

Attic Air Sealing & Blown-In Top-Up - Station District, 1950s Bungalow

Attic floor with visible gaps around chimney chase and top plates, existing insulation disturbed by prior work — Before: Original rock wool disturbed by electrical upgrades, large gaps at chimney chase and partition walls, recessed can lights unsealed.

Sealed attic floor with new blown-in fiberglass over properly air-sealed penetrations — After: Fire-rated foam and metal flashing at chimney, sealed can light covers, blown-in Knauf fiberglass to R-49.

This Station District bungalow still had its original rock wool, which isn’t bad insulation but had been trampled by three generations of electricians and HVAC techs. Worse, the chimney chase - a three-story brick column running through the center of the house - had a half-inch gap around it that was pulling conditioned air straight into the flue cavity. We used fire-rated foam and sheet metal flashing to seal the chase, installed ten pre-approved can light covers, then blew Knauf fiberglass to R-49. The blower door started at 5,100 CFM50, which is enormous for a 1,200-square-foot house, and finished at 2,400. The homeowner said the furnace used to run constantly; now it cycles and rests.

Insulation Removal After Rodent Damage - Near Logan High School, 1990s Tract Home

Attic insulation contaminated with rodent droppings and nesting material near Logan High School — Before: Fiberglass batts pulled apart for nesting, extensive droppings, chewed electrical wiring visible above insulation.

Clean attic deck with new blown-in insulation and rodent-proofing at entry points — After: Full HEPA vacuum removal, disinfected deck, sealed entry points with hardware cloth, new blown-in cellulose to R-38.

The roof rat problem in Union City isn’t subtle once they’re in your attic. This home near Logan High School had bats that had been nesting in the fiberglass for two seasons, with droppings compacted into the lower layers and wiring chewed down to copper. We don’t do pest control, but we do the cleanup after. Our crew suited up, HEPA-vacuumed every square inch of decking, applied disinfectant, then worked with the homeowner’s pest company to seal entry points with hardware cloth before we blew new cellulose. Under Haven Standard: we don’t put new insulation over contamination, and we document the clean deck with photos before anything goes back in.

Want Results Like These?

Contractor installing attic insulation batts with a depth measurement gauge — Want Results Like These?

Every job above started the same way: a homeowner called (650) 381-1512, we scheduled a walk-through, and they got a written price before any work started. No exceptions, no surprises. We serve Union City and 17 surrounding communities, with live people answering calls 24/7. If you’ve got a competing quote, bring it in - we’ll read it with you line by line under our Free Second Opinion. Call (650) 381-1512 or stop by to talk through what your attic or crawl space actually needs.

Written by Wes Okafor, Owner at Topside Attic Insulation Union City, serving Union City since 2016.

Before & After Gallery - Topside Attic Insulation Union City