Crawl Space Encapsulation Sealed to 50 to 55% RH Year-Round in NE/IA
Epp Foundation Repair has installed encapsulation systems across Nebraska, Iowa, Kansas, and Missouri since 1994. BBB A+ accredited, two-time Integrity Award winner.
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A local specialist will inspect your foundation, walk you through the findings, and send a clear estimate, no cost, no pressure.
Crawl Space Encapsulation: how it works and when it's the right call.
The mechanism is moisture-source elimination. A vented crawl in Nebraska or the surrounding states pulls 60 to 75% RH summer air in through the vents, where it hits cooler subfloor surfaces and condenses. Dave Epp has measured 80%+ RH and visible water beads on joists in vented crawls during August. Encapsulation reverses that by physically blocking three moisture pathways at once. The 10-mil or 20-mil reinforced polyethylene sheet stops ground moisture evaporating up from the dirt (a typical 1,500 sq ft crawl floor evaporates 10 to 15 gallons of water per day in summer per Building Science Corp research). Sealed vents stop humid exterior air infiltrating. The dehumidifier removes any residual moisture from air leaks and occupant activity above. Together they hold the crawl at 50 to 55% RH stable. Below the 60% threshold where mold germinates and wood begins absorbing moisture from the air.
What is Crawl Space Encapsulation?
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How we install crawl space encapsulation.
Step 01.On-Site Assessment and Moisture Mapping
Epp Foundation Repair inspects the crawl floor, walls, sill plate, and existing ventilation, takes moisture readings on joists and subfloor, and identifies any active water entry, standing water, or grading issues. Dave Epp's rule: never encapsulate over an active water problem. Drainage and sump work get sequenced first.
Step 02.Drainage and Water Control First (If Needed)
When the assessment finds bulk water entering the crawl, Epp installs interior perimeter drainage and a crawl space sump pump before any vapor barrier goes down. Sealing a wet crawl traps water and accelerates rot. Many NE and IA crawls Epp inspects need drainage work before encapsulation.
Step 03.Vapor Barrier Installation
Epp crews lay 20-mil reinforced polyethylene for crawls with foot traffic or storage, 10-mil for non-traffic crawls. The sheet covers the entire dirt floor and extends up the foundation walls to the sill plate. Seams overlap 6-12 inches, sealed with butyl tape; mechanical fasteners and termination bars secure the barrier to the walls.
"I've crawled into more wet crawl spaces in Nebraska and Iowa than I can count since 1994, and the pattern is always the same. A vented crawl in our climate is a humidity pump running the wrong direction. Sealing it the right way, with a real vapor barrier and a sized dehumidifier, is the only thing that holds the humidity down through an Omaha August. Anything less is theater."
Care and expertise from a team that's been doing this since 1994.
Epp Foundation Repair is locally owned and operated, with crews dedicated exclusively to foundation, basement, and concrete work across the Midwest.
Foundation repair, waterproofing, and concrete leveling are our entire focus, not a sideline.
Three decades of experience with Midwest soils, basements, and weather conditions.
Recognized in 2011 and 2016 for ethical business practices and customer transparency.
Every repair comes with a written Epp warranty, from 1 year to the lifetime of the structure depending on the product.
Answers to common questions about Crawl Space Encapsulation.
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Crawl Space Repair warning signs this solution resolves.
Each problem sign below is a symptom this solution is engineered to fix. See how we diagnose it before we recommend this method.
Moisture in Crawl Space
Epp Foundation Repair has been encapsulating crawl spaces across Nebraska, Iowa, Kansas, and Missouri since 1994, dropping relative humidity from 75%+ down to a stable 50 to 55%. The threshold where mold cannot colonize.
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High Indoor Humidity
Epp Foundation Repair has diagnosed high-humidity calls across Nebraska, Iowa, Kansas, and Missouri since 1994 by tracing the cause to the crawl space first. BBB A+. BBB Integrity Award 2011 and 2016.
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Mold and Mildew
Epp Foundation Repair has identified and stopped the water sources behind crawl-space mold across Nebraska, Iowa, Kansas, and Missouri since 1994. BBB A+. BBB Integrity Award 2011 and 2016.
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Crawl Space Mold
Epp Foundation Repair has diagnosed crawl space moisture conditions across Nebraska, Iowa, Kansas, and Missouri since 1994. Mold spores exist in every crawl space. They only colonize when humidity stays above 60% for 48 hours or more.
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Deteriorating Insulation
Fiberglass batts drooping between your floor joists or falling to the crawl space dirt. The insulation itself is the symptom. The cause is humid air and ground moisture that the insulation can no longer hold back.
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Groundwater Seepage
Epp Foundation Repair has been installing interior crawl space drainage and sump systems across Nebraska, Iowa, Kansas, and Missouri since 1994. The only permanent answer to seepage driven by a high spring water table.
Learn moreServing Nebraska, Iowa, Kansas & Missouri.
Local crews based in five regional offices, dispatched daily across four states. If your town isn't listed, call us: we likely serve your area.
- Omaha, NE
- Lincoln, NE
- Topeka, KS
- Sioux City, IA
- Bellevue, NE
- St. Joseph, MO
- Council Bluffs, IA
- Grand Island, NE
- Papillion, NE
- Kearney, NE
Take the first step toward a healthy home.
A straightforward path from initial inspection to completed repairs.
Schedule your inspection.
A local specialist visits your home, evaluates the foundation, and answers your questions on site. No cost, no obligation.
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Our own trained crews complete the work on schedule and back it with a written Epp warranty, set out in your contract.
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- A Customized Repair Estimate within one business day
- No cost, no obligation, no high-pressure sales
Expert guidance on protecting your home.
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Five regional offices across the Midwest.
St. Joseph, MO 64506