GreenFiber Attic Air Sealing: The West Hollywood Owner’s Guide
We stock and install GreenFiber-compatible attic air sealing assemblies in West Hollywood, with most residential jobs running between $380 and $720 installed, depending on attic square footage and how many top-plate penetrations need sealing. Same-day service is available when you call before noon. Homeowners usually discover the problem when their GreenFiber cellulose insulation was installed over unsealed gaps, or when they feel drafts despite a full attic, or when a home energy audit flags the bypass.
Seal the leaks first. Then insulate. The R-value on the bag assumes you did it in that order.
Which GreenFiber Models This Applies To
GreenFiber manufactures loose-fill cellulose insulation, not standalone air-sealing hardware, so the “GreenFiber attic air sealing” we’re called about is the sealing work performed before or alongside GreenFiber cellulose installation. The compatibility question is whether your home was properly sealed for the GreenFiber product that was blown in. We see this most often with GreenFiber Sanctuary (the stabilized cellulose line) and GreenFiber All Borate, both common in West Hollywood’s 1920s-1950s bungalows and mid-century apartments.
To identify what you’re working with, check the bag remnants or documentation from your original install. GreenFiber Sanctuary has a higher density rating (1.5-1.8 lbs/ft³ settled) and is often specified for West Hollywood’s Title 24 compliance jobs. If your attic has GreenFiber with no air-sealing layer beneath it, the top plates, electrical penetrations, and can-light housings are likely leaking conditioned air directly into the vented attic space. We carry fire-rated caulk, intumescent sealant, and rigid foam baffles that mate correctly with GreenFiber’s specified coverage depths. Topside Attic Insulation West Hollywood is an independent service provider, not affiliated with GreenFiber.
For the OEM-versus-aftermarket decision: GreenFiber does not sell a branded air-sealing kit, so any contractor claiming “genuine GreenFiber seals” is repackaging standard building-science materials. We use Owens Corning FoamSealR, Johns Manville intumescent acrylic, and Knauf EcoSeal - all specified to work with cellulose depths of 10-16 inches, which is what GreenFiber calls for in West Hollywood’s climate zone (CEC Climate Zone 6, marine-influenced with cooling-dominated loads).
Signs Your GreenFiber Attic Air Sealing Is Failing
- Dust streaking on ceiling drywall below the attic hatch. This means air is moving from the conditioned space into the attic through gaps in the top plates, carrying fine particles with it. In West Hollywood, we see this constantly in Spanish Colonial revivals near Fountain Avenue where the original plaster lath meets modern framing with no seal.
- Hot rooms in summer despite running the AC continuously. Unsealed can-light housings and duct boots act as chimneys, pulling 140°F attic air down into your ceiling cavity. GreenFiber cellulose slows conduction but does nothing for convection through a 1-inch gap.
- Ice damming or moisture staining on the roof deck. Warm, humid interior air hits the cold sheathing and condenses. In West Hollywood’s mild climate this presents as black mold spotting rather than ice, especially north-facing roofs that stay cool and damp through June.
- Blower-door test showing little improvement after insulation was added. We recently tested a home near Santa Monica Boulevard that had 14 inches of GreenFiber but still read 3,800 CFM50 - the cellulose was doing its job, but the air was walking right around it through unsealed plumbing chases.
- Rodent activity in the insulation. Gaps around vent stacks and electrical masts create highways. Once they’re in, they compress the GreenFiber and destroy the R-value. We find this in West Hollywood’s flat-roofed duplexes where multiple trades have punched through the ceiling over decades.
Before
AfterReplacement Cost & What’s Included
Most GreenFiber attic air sealing jobs in West Hollywood run $380 to $720 for attics between 800 and 1,800 square feet. The low end covers a straightforward top-plate seal with fire-rated caulk on a single-story home with good attic access. The high end includes multiple can-light enclosures, duct boot sealing, and a chimney dam - common in the two-story courtyard apartments off Melrose.
| Component | Typical Range |
|---|---|
| Top-plate sealing (per linear foot) | $3.50 - $5.50 |
| Can-light enclosure (fire-rated cover + seal) | $85 - $140 each |
| Duct boot seal and mastic | $45 - $75 each |
| Attic hatch weatherstrip and insulation cap | $120 - $180 |
| Blower-door test (before and after) | $225 - $295 |
Every job includes our Documented Photo Record, the written scope signed before work starts, and before-and-after blower-door numbers so you can verify the result. The 365-Day Done Right Promise applies. Call (213) 306-2607 for a written price - estimates are free.
DIY or Call Us?
Here’s what you can safely check yourself: look at your attic hatch - is there a gasket? Peek at the top plates where interior walls meet the ceiling - do you see gaps or daylight? These are visual checks, not repairs.
Where DIY goes wrong: working in a vented attic in West Hollywood summer heat is genuinely dangerous without hydration and egress planning. More critically, can-light housings in pre-1985 homes may contain asbestos-containing fireproofing, and disturbing them without testing violates Cal/OSHA. Sealing around chimney flues requires intumescent materials rated to 1,800°F - standard caulk off-gasses and fails. We carry a combustible-gas detector and thermal camera on every truck to locate leaks without guesswork. If your GreenFiber was installed without a prior seal, the fix is almost always faster and safer with a crew that has done it before. Call (213) 306-2607.
FAQs
Properly installed air sealing lasts the life of the building envelope, 25-40 years, but only if the original materials were specified correctly. In West Hollywood, we find caulk failures at the 8-12 year mark when non-UV-stable products were used near soffit vents, or where vibration from the 405 freeway corridor has cracked rigid foam at top plates. We warranty our sealant work for one year under the 365-Day Done Right Promise, and the materials themselves carry manufacturer warranties of 10-50 years depending on product. Call (213) 306-2607 if you’re seeing new drafts - estimates are free.
Partial repair is possible if the original sealing was done competently and only specific penetrations have failed - a dried-out plumbing vent seal, a dislodged baffle. We do this often in West Hollywood’s rent-controlled buildings where owners need targeted fixes. However, if the GreenFiber was blown over an unsealed attic floor, partial repair is throwing good money after bad; the blower-door test will show leakage across the entire plane. We provide the test numbers so you can decide with data, not sales pressure. Call (213) 306-2607 for a free second opinion on any written estimate.
A typical West Hollywood single-family attic takes one crew one day, 6-8 hours including setup, sealing, and the blower-door verification. Two-story homes or apartments with multiple attic zones may run into a second day. We text you a 30-minute arrival window and a named technician under Haven Standard: Arrive on schedule. Call (213) 306-2607 to book.
Yes - FoamSealR, intumescent acrylic, fire-rated caulk, and pre-formed baffles for GreenFiber’s specified depths are on our trucks daily. We also stock Reflectix radiant barrier components for homes doing the full envelope upgrade. Same-day availability in West Hollywood when you call before noon. Call (213) 306-2607.
Written by Wes Okafor, Owner, Topside Attic Insulation West Hollywood at Topside Attic Insulation West Hollywood, serving West Hollywood and nearby areas.