Demilec Crawl Space Encapsulation Nationwide

Demilec Crawl Space Encapsulation: The Houston Owner’s Guide

We stock and install Demilec-compatible crawl space encapsulation materials across Houston, with most full encapsulations running between $4,800 and $9,200 depending on square footage, access height, and whether your existing vapor barrier is salvageable. A straightforward liner replacement on a 1,200-square-foot crawl space typically lands around $5,500 to $6,800, and our crews can usually start within 48 hours of your written estimate. Most Houston homeowners call us after noticing a musty smell creeping into the living room or seeing condensation on the underside of floor joists during a humid stretch, then find the existing liner torn, sagging, or pulled away from the foundation walls.

Call (430) 226-1334

Before a single panel comes off the truck, Neil Barron walks your crawl space twice. Once to map what’s there now, once to figure out exactly what the family above needs. He puts the material spec and the price in writing before we schedule the install, and that number doesn’t move unless the scope changes.

Which Demilec Models This Applies To

We work with the full Demilec line as it applies to crawl space work: Heatlok HFO Pro, Heatlok XT, Sealection 500, and the Demilec closed-cell spray foams commonly specified for rim joist sealing and crawl space wall insulation in Houston’s climate zone 2. The encapsulation liner itself is most often paired with Demilec’s spray foam applied to the perimeter band and crawl space walls, so the compatibility question is less about the liner brand and more about how the foam bonds to the masonry and what moisture conditions exist below grade.

The most common compatibility gotcha in Houston: Heatlok HFO Pro needs a substrate temperature above 45°F and relative humidity below 85% at application time, which sounds easy until you’re in a crawl space in July with 90% ambient humidity and a dehumidifier that hasn’t run in three years. We bring commercial dehumidifiers and moisture meters to every Demilec job so the foam actually cures the way the spec sheet says it will. On the liner side, we stock 12-mil and 20-mil reinforced poly in 10-foot and 12-foot rolls, which covers most standard Houston pier-and-beam layouts without excessive seaming. If you’re looking for an exact match to what’s already under your house, the existing liner’s thickness is printed on the material face near the overlap, and any product tag still attached to the foam will carry the Demilec lot number.

As for OEM versus aftermarket, Demilec doesn’t manufacture the encapsulation liners that carry their spec on residential jobs. The foam is strictly Demilec OEM and we won’t substitute it. The liner, seam tape, and mechanical fasteners are supplied to Demilec’s thickness and permeance ratings, and we stock equivalents that meet or exceed the original spec. You get the same field performance, and you’re not paying a name-brand markup on a roll of poly.

We also keep Reflectix on the truck for radiant barrier applications in vented crawls and underfloor insulation retrofits where a foil-faced product makes more sense than foam.

Signs Your Demilec Crawl Space Encapsulation Is Failing

• Damp, earthy smell in the living room. The encapsulation liner has torn or pulled away from the foundation wall, letting ground moisture migrate up through the floor system. In Houston’s clay soil, this shows up fast after the spring rains.
• Visible condensation on ductwork or floor joists. Warm humid air is still entering the crawl space and hitting cooler surfaces. This usually means the liner seam tape has failed, or the foam at the rim joist has de-bonded from the concrete.
• Sagging or puddled liner with standing water on top. The liner was not sealed to the piers and walls properly, or the crawl space has a drainage problem that predates the encapsulation. Water should never pool on top of a working liner.
• Floor feels spongy or hardwood shows cupping. Moisture has been rising into the subfloor long enough to affect the wood. By the time you feel it underfoot, the vapor barrier has been compromised for months.
• Insulation falling from between floor joists. Fiberglass batts in the crawl space ceiling have absorbed enough moisture to lose their friction fit. This often happens above a failed or incomplete liner and is a sure sign the encapsulation stopped doing its job.

Replacement Cost & What’s Included

Here’s how Demilec crawl space encapsulation pricing breaks down in Houston, based on a typical 1,200-square-foot vented crawl with average access:

What moves the number: access height (a 24-inch crawl is a slower job than a 42-inch crawl), the condition of your subfloor, whether old insulation needs removal, and how much foam the rim joist requires. Every quote includes liner material, seam tape, fasteners, all labor, cleanup, and our written price before work begins. Our 365-Day Done Right Promise applies to the whole job: if a seam fails or the liner pulls away within the first year, we come back and fix it. No debate, no fine print.

DIY or Call Us?

You can safely check a few things yourself: look for standing water, visible tears, and whether the liner is still attached at the foundation wall. Use a flashlight, wear a respirator if you see mold, and don’t disturb anything you suspect contains asbestos. What you shouldn’t DIY is the fix. Re-taping a seam while lying on your back in 18 inches of clearance, with Houston’s summer humidity and a headlamp, is how liners end up worse than before. And Demilec two-component spray foam is two chemicals mixed under pressure at the gun tip. That’s not a weekend project. That’s a call to (430) 226-1334, where a live person answers and we put a number in writing before anyone crawls under your house.

Tell me what’s in the room on the other side of that wall, and I’ll tell you exactly what goes between it. That’s how Neil approaches every quote, and it’s why we walk the job twice before the written price lands in your inbox.

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