Fast, Reliable Crawl Space Encapsulation & Vapor Barrier Across Lewisville
If you own a Lewisville home built between 1978 and 1995, your crawl space likely has original vapor barrier material that’s torn, sagging, or long gone. That means humid Texas air moves through your foundation every single day, carrying moisture into floor joists and ductwork. We’re Topside Attic Insulation, and our Crawl Space Encapsulation & Vapor Barrier crews serve Lewisville daily. Call (218) 261-7714 and a live person answers, 24/7. We’ll schedule a walkthrough, give you a written price before any work starts, and document everything with photos before we leave.
Why Topside Attic Insulation Is Lewisville’s Preferred Crawl Space Encapsulation & Vapor Barrier Company
Lewisville homeowners keep calling us back for one reason: we seal first, then insulate. That order matters more in Lewisville than almost anywhere else in the metroplex. The pre-2001 code housing wave left tens of thousands of slab-on-grade and vented crawl homes with fiberglass batts that have absorbed decades of moisture and fallen away from the floor structure. Throwing new insulation over an unsealed crawl space would be a waste of money. We air-seal rim joists, piers, and penetrations before any insulation goes in, then publish before-and-after blower-door numbers on every applicable job so you can see the actual performance change.
Our technicians are background-checked and uniformed. Wes Okafor leads the team, and under The Haven Standard we’ve completed 9,000+ homes since 2016 with a written price before work started on every one. That’s not a slogan. It’s Clause 1 of how we operate. Lewisville customers in neighborhoods like The Colony, Castle Hills, and the older streets near Main Street all get the same treatment: named technician, text when we’re on the way, and a documented photo record when we leave.
Our Crawl Space Encapsulation & Vapor Barrier Services in Lewisville
Crawl Space Vapor Barrier
A vapor barrier alone won’t solve what Lewisville’s expansive clay soil does to a crawl space. The ground moves seasonally; it swells when wet and shrinks when dry. That movement cracks foundation vents and rim joists, tears thin 6-mil plastic laid directly on the dirt, and reopens moisture paths within a few seasons. Our Lewisville crews install 12-mil reinforced vapor barrier, sealed up stem walls and around piers with proper mechanical fastening, so soil movement doesn’t rip it apart. We also seal the foundation vents that most original builders left open year-round.
Crawl Space Encapsulation
Encapsulation is the complete approach: air seal the rim joists, close the vents, line the floor and walls with reinforced vapor barrier, and control the air. On a 1984 brick-veneer tract home near Lake Lewisville, our crew found original R-11 fiberglass batts fallen away from the joists and a ground vapor barrier torn in a dozen places. We removed the failed batts, air-sealed the rim joists with closed-cell spray foam, installed a 12-mil barrier up the stem walls and piers, and added a dehumidifier. The crawl went from 78% relative humidity to under 55% within a week. That’s the difference between a patch job and an encapsulated space.
Crawl Space Insulation
In a vented crawl space, fiberglass batts between floor joists soak up humidity and sag. When they fall away, you’re left with an uninsulated floor and cold spots in January. In Lewisville, where summer attic temps hit 145 to 155°F and February 2021 showed us what a sustained freeze does to under-insulated homes, the insulation has to perform in both extremes. We use closed-cell spray foam on the rim and floor system when encapsulation is part of the job, or rigid foam board on foundation walls in appropriate assemblies. Materials are sourced from Owens Corning, Johns Manville, and Knauf, selected per job, not per sales target.
Crawl Space Moisture Control
Moisture in a Lewisville crawl space comes from three directions: ground evaporation, outside air drawn in through foundation vents, and condensation on AC ductwork. On older homes, the vents are often undersized or blocked by settled soil, which traps humid air and causes rust on ducts and musty odors that drift up through the floor. Moisture control means measuring first, then fixing: a dehumidifier sized to the space, sealed vents, and a barrier system that stops ground moisture at its source. We document the before and after readings so you know what changed.
What happens when you call
- 1
A real person answersNo phone trees - you reach a local pro.
- 2
You get an upfront price rangeHonest numbers before anyone is dispatched.
- 3
A background-checked tech heads outLicensed & insured, dispatched right away.
- 4
You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in Lewisville
We stock common vapor barrier materials, seam tape, mechanical fasteners, and dehumidifier filters for the Lewisville market, so we’re not waiting on shipments when your job is scheduled. Our crews work with materials from Owens Corning for rigid foam board, Johns Manville for batt products where appropriate, and Rockwool for fire-rated assemblies. No proprietary product lock-in. If a competing estimate specifies a certain material, bring it to us. We’ll read it with you and give you a free second opinion on any written estimate.
Common Crawl Space Encapsulation & Vapor Barrier Problems We See in Lewisville Homes
- Vapor barriers torn to shreds within a few years. Lewisville’s expansive clay soil moves seasonally. A thin 6-mil sheet laid loose on the dirt rips at seams, pulls away from piers, and stops doing its job the moment moisture finds a path. Our crews see this on nearly every pre-2001 home we inspect.
- Original fiberglass batts sagging or missing. Humidity in vented crawl spaces destroys fiberglass. The batts absorb moisture, droop, fall, and leave the floor uninsulated. Rodents add damage on top of that. Removal and replacement with a system that doesn’t hold water is step one.
- Foundation vents blocked or undersized. Builders in the 1980s often installed vents that were barely adequate when new. Decades of settled soil and landscaping later, they’re blocked entirely. That traps humid air inside, rusts ductwork, and creates musty smells you notice in the living room.
- Recessed can lights and rim joist penetrations leaking unconditioned air. On older Lewisville homes, the rim joist area around the foundation is rarely air-sealed. Each penetration is a small chimney pulling hot, humid air into the crawl space in July and cold air in February. We find this on nearly every pre-code home in Lewisville.
Pricing for Crawl Space Encapsulation & Vapor Barrier in Lewisville, TX
A crawl space vapor barrier replacement in Lewisville typically runs $1,800 to $4,200 depending on square footage, access, and how much old material needs removal. Full encapsulation, which includes air sealing the rim joists, sealing vents, installing a 12-mil reinforced barrier, and adding a dehumidifier, runs $7,500 to $16,000 for a standard 1,200 to 2,000 square foot crawl space on the older lots near Main Street or the Lake Lewisville subdivisions. Adding closed-cell spray foam insulation at the rim and floor adds $2 to $4 per square foot. Every job starts with a written price. No work starts without one. Call (218) 261-7714 and we’ll schedule a walkthrough, give you that written price, and walk you through what the scope covers line by line.
We Also Serve Cities Near Lewisville
Our Lewisville customers often ask if we handle the surrounding metroplex. Yes. We regularly work in Flower Mound, Carrollton, Plano, and Richardson, applying the same Haven Standard on every job. Scheduling is coordinated from our Dallas-Fort Worth office, and crews dispatch locally so response time stays tight.
Serving Lewisville, TX - Our Local Coverage Area
We’re based in the Lewisville area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
FAQs - Crawl Space Encapsulation & Vapor Barrier in Lewisville
Most pre-2001 Lewisville homes were built with thin fiberglass batts in vented crawl spaces, a configuration that was code-legal then but is deeply flawed on the city’s expansive clay soils. The batts absorb humidity and sag, the vents leak unconditioned air, and seasonal soil movement cracks foundation components. Encapsulation on these homes requires removing failed insulation, sealing structural gaps, and installing a barrier system designed for moving ground. It’s more work than a newer build, and skip the shortcuts.
Winter Storm Uri exposed how little protection pre-code insulation levels provide against sustained sub-freezing temperatures. Homes that lost heat through unsealed crawl spaces and under-insulated floors saw frozen pipes and cold slabs. Encapsulation with an air-sealed rim joist system and a dehumidifier reduces that heat loss year-round. If you’re budgeting for crawl work, ask whether the scope includes air sealing at the rim and foundation perimeter. It should. Call (218) 261-7714 for a written scope.
Look for plastic that’s torn, pulled away from the stem walls, or missing entirely. Check if the piers are wrapped or if soil movement has shifted the barrier. Sniff for musty odors, look for rust on ductwork, and check whether foundation vents are blocked by settled soil. If you can see dirt anywhere in the crawl space, your barrier has failed. We document all of this in our photo record on every visit. A walkthrough is free.
No. Adding insulation over an unsealed, vented crawl space in Lewisville means the new material absorbs the same humidity that ruined the old batts. You’d be paying twice. Air seal the rim joists, close the vents, and install a barrier system first. Then insulation has a chance to perform. That’s the order we follow on every single Lewisville job, and we publish the blower-door numbers before and after so you can see the difference.
Yes. A documented encapsulation with before-and-after moisture readings and a written warranty is a selling point that appraisers and buyers recognize, especially in Lewisville’s 1978 to 1995 housing stock where most homes still have original crawl spaces. The 365-Day Done Right Promise transfers with the work. If it’s not done right, we make it right. Call (218) 261-7714 for a written estimate and exactly what the scope includes.
Written by Wes Okafor, Owner at Topside Attic Insulation, serving Lewisville under The Haven Standard since 2016.