MoldEx & LumberKote2026-10-29T13:15:06-05:00

Crawl Space Mold Treatment & Wood Sealing in Washington, D.C.

Treat existing mold and help protect crawl space wood against future growth with MoldEx and LumberKote from NV Waterproofing and Foundation Repair.

Why Mold Gets Started in Washington, D.C. Crawl Spaces

Crawl space mold grows when moisture lingers around wood framing. Humid air, damp soil, leaks or water intrusion can raise moisture levels, setting up conditions where mold can develop on joists and subfloors. You may spot white or gray growth, musty odors or shifts in the floors above.

If it goes unaddressed, ongoing moisture can contribute to dry rot damage, softened wood and sagging floors.

Symptoms

Signs You May Need Crawl Space Mold Treatment

Mold in a crawl space isn’t always obvious from inside the house. Some signs appear on the wood below, while others surface as odors or changes to the floors above. It may be time for a professional inspection if you notice:

  • White, gray or dark growth on floor joists or subflooring
  • Lingering musty odors in the crawl space or living areas
  • Wood that looks damp, stained or discolored
  • Condensation or high humidity beneath your home
  • Cupping or other changes in the floors above
  • Mold that returns after cleaning

Our MoldEx & LumberKote Crawl Space Solutions

  • Treats Mold on Crawl Space Wood

    MoldEx Mold Treatment

    MoldEx goes directly on affected floor joists, subflooring and other wood surfaces to treat existing mold and staining. The treatment reaches the areas where growth is present, helping clean up and restore the appearance of the wood. After treatment, crawl space framing looks cleaner and is ready for any additional moisture-control or protective measures the home may need.

    • Treats existing mold growth on crawl space framing
    • Applied straight to affected joists, beams and subflooring
    • Helps address mold ahead of protective sealing or other crawl space improvements
    • Treats hard-to-reach wood surfaces throughout the crawl space
    • Helps eliminate visible mold as part of a broader moisture-control strategy
  • Protects Crawl Space Wood After Treatment

    LumberKote Framing & Subfloor Sealer

    LumberKote is a protective coating applied to crawl space floor joists, beams and subflooring. It creates a durable barrier over the wood to help protect treated or vulnerable surfaces from future moisture-related damage and mold growth. After application, the framing has a clean, uniform finish that provides a visible layer of protection throughout the treated area.

    • Helps protect wood against moisture, moisture-related damage and wood-destroying mold
    • Built on advanced polymer technology
    • Certified FEMA Flood Grade rated
    • Helps dry and stabilize the lumber’s moisture content, even when moisture-related damage has already begun
    • Includes a transferable, 30-year warranty
How It Works

What to Expect on Treatment Day

How to Help Keep Crawl Space Mold from Coming Back

Treating existing mold is only half the solution. If excess moisture stays in the crawl space, conditions can become favorable for new growth. That’s why NV Waterproofing and Foundation Repair also looks for the source of the moisture rather than focusing only on what’s visible on the wood.

Depending on the crawl space, the solution can include controlling humidity, addressing water intrusion or sealing the space from outside air and ground moisture. Encapsulation and other crawl space repair solutions can help produce a drier environment and limit the conditions mold needs to grow.

Benefits

Crawl Space Mold Treatment You Can Count On in Washington, D.C.

Mold in your crawl space can have more than one cause, so treatment shouldn't be one-size-fits-all. NV Waterproofing and Foundation Repair assesses your crawl space for mold growth, wood condition, humidity, water intrusion and other conditions that could be contributing to the problem.

We'll recommend the right approach for your home, whether that involves MoldEx, LumberKote or additional moisture-control solutions. Schedule a free crawl space inspection in Washington, D.C. and get a written estimate for the repairs we recommend.

What To Expect

Ready to get started?

Schedule a free estimate to start your repair journey with Thrasher.

Schedule your inspection

Fill out our form or give us a call to book your inspection. Share what you’ve noticed so we can send the right expert to your home.

Full home
inspection

An expert will inspect the problem area and surrounding conditions, including soil movement, drainage, structural integrity, and any related concerns.

Clear explanation
of findings

We’ll walk you through what we’re seeing in easy-to-understand language so you know the root cause of the issue, not just the symptoms.

Review recommendations

If repairs are needed, we’ll outline your options, pricing, and timeline so you can make the best decision for your home.

Schedule your free inspection—

It'll only take
a minute

Meet with a trusted expert, and get
clear answers about your home.

"*" indicates required fields

1Your Info
2Schedule Your Inspection
3Review & Submit

Customer Information

Don't just take our word for it

See what our customers have to say about our work.

Before & after photos

Check out before and after photos from some of our completed projects.
  • Sunken Concrete Step Repair in Stephens City, VA

    This Stephens City, VA homeowner was dealing with a sunken concrete front step that had settled over time, creating an uneven entryway and a noticeable tripping hazard near the front door. Sunken concrete steps can make everyday foot traffic unsafe for homeowners, guests, and delivery drivers, while also taking away from the home’s curb appeal. Our concrete repair team lifted and leveled the front step back to its proper position, creating a safer, more stable walkway and entrance. This concrete step repair helped reduce the risk of falls, improved the look of the front entry, and gave the home a cleaner, more welcoming appearance. The homeowner was thrilled with the outcome — a big transformation that improved both safety and curb appeal!

  • Basement Waterproofing in Winchestor, VA

    A homeowner in Winchester, VA, was struggling with a failing sump pump that couldn’t keep up during heavy rainstorms, leaving their basement vulnerable to water intrusion. The lack of a reliable backup system also left them worried about potential flooding during power outages. Frustrated and seeking a dependable solution, they contacted NV Waterproofing and Foundation Repair, a trusted basement waterproofing company in Winchester, VA.

    After assessing the situation, we replaced their old sump pump with a state-of-the-art TripleSafe Sump Pump system. This advanced system includes three levels of protection: a primary pump, a secondary pump for heavy water flow, and a battery backup to ensure the basement stays dry even during power outages. The homeowner now has peace of mind knowing their basement is fully protected, no matter the weather.

  • Pool Deck Leveling in Manassas, VA

    A homeowner in Manassas, VA, quickly realized their dream backyard pool was at risk when the surrounding concrete pool deck began to show serious problems. Uneven and sunken slabs created tripping hazards and unsightly cracks, making both safety and aesthetics a challenge for anyone using the space. Additionally, water from rain and pool use was pooling in low spots, causing slippery surfaces and further soil erosion beneath the deck. These issues not only threatened the safety of family and guests but also compromised the value and enjoyment of the home.

    Seeking an effective solution, the homeowner reached out to our team for a professional assessment. We identified the main cause of settlement: soil erosion under the slabs—a common issue in Manassas due to its clay-rich ground and fluctuating moisture. To address both the immediate hazards and prevent future damage, we recommended our two-part approach: the cutting-edge PolyLevel® concrete leveling system and NexusPro® Joint Sealant.

    The repair process began with drilling small holes into the affected concrete slabs, allowing us to inject high-strength PolyLevel® polyurethane foam beneath the surface. As the foam expanded, it filled voids, stabilized the soil, and gently lifted the slabs back to their original positions. The process was quick, clean, and minimized disruption, giving the pool deck a level, safe surface once again. PolyLevel® foam is waterproof and lightweight, reducing the risk of future settling and ensuring long-term durability, even in a wet poolside environment.

    To provide further protection, we sealed all cracks and joints with NexusPro® Joint Sealant. This flexible, weather-resistant sealant prevents water from seeping beneath the slabs, protecting the soil and concrete from additional erosion. The result was a clean, finished appearance that not only improved the look of the deck but also safeguarded it for years to come.

    Thanks to modern concrete leveling technology, the homeowner’s pool deck was transformed from a liability into a safe and attractive outdoor gathering space. The project was completed in a single day, with minimal mess and immediate results, giving the homeowner peace of mind and renewed pride in their backyard. If you’re facing similar issues with your pool deck in Manassas, VA, the PolyLevel® system and NexusPro® Joint Sealant offer a fast, effective, and lasting

Our service area

Proudly Serving Northern Virginia, D.C., and Suburban Maryland

Frequently Asked Questions

Can I just spray the mold on my floor joists myself? 2026-10-05T11:29:52-05:00

Spraying visible mold can clean the surface, but it may not address growth in other areas or the moisture problem causing it. Some household cleaners can also discolor or damage wood without offering lasting protection. A crawl space professional can determine how widespread the problem is, treat affected surfaces and pinpoint what needs to change to help keep the mold from coming back. 

How much does crawl space mold treatment cost in Washington, D.C.?2026-10-05T11:29:06-05:00

Crawl space mold treatment costs vary depending on the size of the crawl space, how much wood is affected, the treatment required and whether moisture or structural problems also need to be addressed. Since every crawl space is different, an inspection is the best way to determine the scope of work. NV Waterproofing and Foundation Repair provides free inspections and estimates for homeowners in Washington, D.C..

Does LumberKote prevent mold from coming back?2026-10-05T11:28:18-05:00

LumberKote helps protect the crawl space wood, but lasting protection also depends on controlling the moisture that contributed to mold or wood damage in the first place. When a crawl space has high humidity, water intrusion or other moisture problems, NV Waterproofing and Foundation Repair may recommend additional solutions to keep the space drier and help protect the framing long term. 

How long does MoldEx and LumberKote treatment take?2026-10-05T11:27:34-05:00

Treatment time depends on how large the crawl space is, the amount of affected wood and whether other repairs or moisture-control measures are needed. MoldEx and LumberKote are often part of a larger crawl space repair project, so the overall timeline varies by home. NV Waterproofing and Foundation Repair will explain the recommended treatment and the expected installation timeline once we’ve inspected your crawl space. 

Do I need mold treatment before crawl space encapsulation?2026-10-05T11:26:40-05:00

If active mold is present, it should usually be addressed before the crawl space is encapsulated. Encapsulation helps control the moisture conditions mold needs to grow, but it won’t remove existing growth from joists or subflooring. NV Waterproofing and Foundation Repair can evaluate both the mold and its moisture source to determine whether treatment, encapsulation or a combination of solutions makes sense.

Is mold in a crawl space dangerous to my family?2026-10-05T11:25:38-05:00

Crawl space mold shouldn’t be ignored. Mold spores and musty odors can travel with air from the crawl space into the living areas above, potentially impacting indoor air quality. The level of concern depends on the type and extent of the growth and individual sensitivities. A professional inspection can evaluate the extent of visible growth and, just as importantly, the moisture conditions letting it develop. 

Related pages

Service Areas

NV Waterproofing has locations throughout Northern Virginia, D.C., and Suburban Maryland.

Resources

Access valuable resources to help keep your home healthy and your family safe.

Our Promise

At NV Waterproofing, we pride ourselves on providing permanent solutions, and stand behind our work with industry-leading, fully transferable warranties and guarantnees.

Schedule your free inspection today

Don’t let unanswered questions about your
home worry you any longer.
Go to Top