Demilec Attic Air Sealing Nationwide

Demilec Attic Air Sealing: The Burbank Owner’s Guide

Demilec-compatible attic air sealing in Burbank typically runs $1,800-$3,400 installed for a complete top-plate and penetration seal on a single-family home, and we stock the full Demilec foam and accessory line for same-day starts. Most Burbank homeowners discover the problem when their summer cooling bill spikes 30-40% above neighbors with similar homes, or when an HVAC tech points out the attic is pulling conditioned air through recessed can lights and top-plate gaps faster than the system can replace it. We see this exact pattern in Magnolia Park ranch homes built between 1955 and 1975, where the original construction never included air sealing and later insulation was blown straight over the leaks.

Call (213) 816-1699

Which Demilec Models This Applies To

Demilec operates under the Huntsman Building Solutions umbrella, and the products we install in Burbank attics fall into two main lines: Heatlok HFO Pro, a closed-cell spray foam rated at R-7 per inch, and Demilec SEALECTION 500, an open-cell option at R-3.7 per inch used primarily for large cavity fills where structural moisture management is less critical. The right choice depends on your roof deck configuration and whether your attic is conditioned or vented.

To identify what you currently have, check the application sticker on any exposed foam surface, usually found near the attic access hatch or on a tag left by the original installer. The batch code starts with a four-digit date followed by “HLK” for Heatlok or “SL5” for SEALECTION. If the foam has yellowed and become powdery at the surface, that’s UV degradation, not a product failure, but it tells us the original install date and whether the wrong foam type was used for a hot Burbank roof deck.

We source OEM Demilec foam and also carry compatible aftermarket sealants from Icynene and Johns Manville for hybrid applications. The OEM-versus-aftermarket decision matters most when we’re tying into existing Demilec foam; chemical incompatibility between different manufacturer’s isocyanate formulations can cause delamination at the bond line, something we’ve documented in three Burbank re-dos since 2019.

Signs Your Demilec Attic Air Sealing Is Failing

• Uneven room temperatures despite new insulation. You added R-38 batts two years ago but the back bedroom still runs six degrees hotter in July. The insulation is doing its job; the air is bypassing it through unsealed top plates and wire penetrations, a thermal bypass that moves conditioned air faster than conduction through the ceiling can be stopped.
• Dust streaking around ceiling registers and can lights. Dark lines on the ceiling paint mean your attic is operating under negative pressure, pulling attic air (and fiberglass particles, rodent droppings, and whatever else is up there) through every gap. In Burbank’s Santa Ana wind seasons, this pressure differential intensifies and the streaking accelerates.
• Ice damming or condensation on nail pops in winter. Warm moist air hits the cold roof deck, condenses, and freezes at the eaves. The Demilec seal was either never applied at the eave edge or has pulled away from the sheathing due to seasonal expansion cycling, something we see more in homes with composite shingle roofs that transfer more heat variation than tile.
• HVAC runs continuously without reaching setpoint. Your 3-ton system was properly sized but now behaves like it’s underrated. The building envelope is leaking at a rate that exceeds the equipment’s capacity, measured in CFM50, a pressurization reading that shows in one number how much air your home loses under standard test conditions.
• Musty odor after rain that clears by afternoon. Moisture is entering through a failed seal at a chimney chase or vent stack, wetting the roof deck, then evaporating when the sun hits. Demilec foam around masonry penetrations fails first in Burbank because the differential expansion between foam and brick or stucco shears the bond over five to seven years.

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Replacement Cost & What’s Included

What drives the range: attic square footage, accessibility (truss height and whether there’s a plywood catwalk), and how much existing foam needs removal before reapplication. We don’t price by the board foot of foam; we price by the seal quality we can guarantee. Every job includes a written scope, a written warranty under our 365-Day Done Right Promise, and before-and-after blower-door numbers so you can verify the CFM50 dropped. The R-value is what the label says. The performance is what the blower-door test says. We care about the second number.

Topside Attic Insulation Burbank is an independent service provider, not affiliated with Demilec or Huntsman Building Solutions. We source materials through standard distribution channels and carry no exclusive or preferred status with any brand.

DIY or Call Us?

What you can safely check: turn off your HVAC, close all windows and doors, and run a bathroom exhaust fan for ten minutes. Hold a lit incense stick near ceiling can lights, electrical outlets on exterior walls, and the attic access hatch. If the smoke pulls horizontally toward the ceiling, you’ve got a pressure leak. Mark the spots with painter’s tape and photograph them. That’s useful diagnostic information, and we’ll use it.

Where DIY goes wrong: spray foam application requires respiratory protection rated for isocyanates, proper substrate temperature control (Burbank attics hit 140°F in August, which can cause off-gassing and poor adhesion), and precise mix ratios that change with ambient humidity. More critically, most homeowners seal the obvious gaps and miss the top plates, which are buried under existing insulation and invisible without moving material. We’ve been called to five Burbank jobs in the past two years where the owner spent a weekend with canned foam, improved nothing measurable on the blower-door test, and then paid us to do the full scope anyway. Call (213) 816-1699 and we’ll give you a written price before any work starts, including a free second opinion on any competing estimate you’ve already received.

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