Demilec Crawl Space Encapsulation Nationwide | Walt’s Insulation

Demilec Crawl Space Encapsulation: The West Hollywood Owner’s Guide

If your Demilec crawl space encapsulation has torn, sagged, or pulled away from the foundation walls, we can match the liner and get it reinstalled, usually within 48 hours in West Hollywood. Typical replacement costs for a Demilec crawl space encapsulation run between $2,800 and $7,500 installed, depending on square footage, access, and whether the existing Demilec spray foam needs patching. Most West Hollywood homeowners discover the problem the same way: a musty smell that won’t quit, higher humidity upstairs, or a look under the house that reveals liner drooping off the piers like wet laundry.

Call (213) 527-4062

We’re independent of Demilec, but we install and repair their systems regularly. If your liner failed, the fix usually isn’t a full redo. It’s matching the material, re-securing it, and sealing the gaps that let moisture back in.

Which Demilec Models This Applies To

Demilec makes spray foam insulation, not the liner itself. In a typical West Hollywood crawl space, the Demilec product is the closed-cell or open-cell foam sprayed on the foundation walls and rim joists, paired with a vapor barrier liner across the floor and up the piers. The failure point is almost always where those two meet.

The most common Demilec products we see in West Hollywood homes are Heatlok HFO Pro (closed-cell), Sealection 500 (open-cell), and the older Heatlok Soy 200. To identify what’s under your house, check for a small white label on the foam near the crawl space entry. If the label’s gone, we can tell by touch and density. Closed-cell feels rigid and hard; open-cell feels spongy and soft.

When matching a liner to your Demilec system, what matters is the liner thickness and the attachment method. We typically work with 12-mil or 20-mil reinforced polyethylene for West Hollywood homes, but older installations might have 6-mil or 8-mil, which tears easily. A 6-mil liner is the crawl space equivalent of a plastic sandwich bag down there. If your handyman installed that, don’t blame the foam.

Signs Your Demilec Crawl Space Encapsulation Is Failing

• Musty smell upstairs within a few days of rain. West Hollywood gets about 14 inches of rain a year, but when it comes, it saturates the clay-heavy soil fast. If the liner has gaps, that moisture rises straight into your floor joists and up through the house.
• Condensation on ductwork or pipes under the house. This means the Demilec foam has delaminated from the foundation wall, creating a cold spot where warm crawl space air condenses. We see this most often on the north-facing walls of older West Hollywood homes near the Hollywood Hills foothills.
• Liner sagging off piers or foundation walls. The liner should sit tight against every surface. If it’s pulling away, the mechanical fasteners or the seam tape gave out. Tape fails before liner does.
• Visible tears or punctures in the vapor barrier. Rats, plumbing repairs, or a careless pest control visit. Any opening wider than a quarter defeats the whole system.
• Wood moisture readings above 16% inside the crawl space. We check this on every job. A working Demilec system should keep wood moisture under 12% year-round. At 20%, you’re inviting mold and wood rot.

Replacement Cost & What’s Included

Here’s what we charge for Demilec crawl space encapsulation repair and replacement in West Hollywood:

• Liner patch and re-secure (single tear, under 10 feet): $400-$900
• Partial liner replacement (up to 400 sq ft): $1,200-$2,400
• Full liner replacement (up to 1,200 sq ft): $2,800-$5,500
• Full Demilec foam re-spray plus new liner (1,200 sq ft): $5,000-$7,500

Every quote includes the liner material, seam tape, mechanical fasteners, removal of the old failing material, and re-securing the Demilec foam where it has separated. Access makes a real difference. A crawl space with 18 inches of clearance costs less to work in than one with 12 inches. West Hollywood’s older Spanish-style bungalows off Fountain Avenue often have tight access hatches that add labor time.

All of our work carries the Done Right Promise: if it’s not done right, we make it right. Lifetime workmanship, in writing.

DIY or Call Us?

You can safely inspect a Demilec crawl space encapsulation yourself. Put on a mask, gloves, and knee pads, grab a flashlight, and look for tears, sagging liner, and damp spots on the piers. If the foam is crumbly when you touch it, it has lost adhesion and needs attention.

What you should not do is attempt to re-spray Demilec foam yourself. Spray foam is applied at high temperature and pressure, and the chemicals are hazardous before they cure. The spray guns used for this aren’t something you rent at the hardware store, and an improper mix ratio leaves you with foam that off-gasses or never sets. For liner repairs, taping a small tear is possible, but most West Hollywood failures we see involve detached liner at the wall junction, which requires proper fasteners and seam technique. Call us at (213) 527-4062 and we’ll tell you over the phone whether it’s worth a service call.

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