What Encapsulation Actually Is
Encapsulation turns your crawl space from an open dirt pit into a sealed, dry part of your home. We cover the ground with a thick, heavy liner. We seal every vent, gap, and hole in the foundation walls. We close and seal the access door. Then we add a dehumidifier built for crawl spaces, so the air stays dry all year. The result is a clean, bright space under your house that protects the wood, the air, and your energy bills.
Think of it this way. Right now, most Baltimore crawl spaces breathe outdoor air. In summer, that air is hot and wet. When it hits the cool surfaces under your house, the moisture drops out — just like water beading on a cold glass. That daily cycle soaks the wood, feeds mold, and rusts anything metal down there. Encapsulation breaks the cycle. No more outdoor air coming in. No more damp ground breathing moisture up. The space stays dry because nothing wet can get in.
This matters more in Baltimore than in most cities. Our summers are long and humid. Our soil is heavy clay that holds water against foundation walls. And our housing stock is old — thousands of rowhomes and colonials built before anyone thought about crawl space moisture. If your home was built before 1980 and the crawl space was never sealed, there is a good chance it needs it.
What a Full Encapsulation Includes
A real encapsulation is a system, not just a plastic sheet on the ground. Here is what we install.
The liner. We use a thick reinforced liner — far heavier than the thin plastic from a hardware store. It runs wall to wall, up the foundation walls, and around every pier. Seams are overlapped and sealed with tape made for the job. When we are done, the dirt is fully covered. Ground moisture cannot rise into the air anymore.
Sealed vents and gaps. Old crawl space vents were designed to "air out" the space. In a humid climate, they do the opposite — they let wet summer air pour in. We seal every vent from the inside with rigid material, then seal the edges. We also seal pipe penetrations, gaps around the access door, and any holes in the foundation or rim joist where outside air sneaks in.
The access door. Most crawl space doors are thin wood or flimsy metal that leaks air. We replace or rebuild the door so it closes tight and seals like it should.
The dehumidifier. This is the heart of the system. We install a commercial-grade dehumidifier made for crawl spaces — not a small home unit that will burn out in a year. It drains on its own to a sump pump or daylight drain, so you never empty a bucket. It holds the humidity in the healthy range automatically.
Drainage first, if needed. If water runs into your crawl space during heavy rain, encapsulation alone will not fix it. We install interior drainage and a sump pump before the liner goes down. Sealing water inside is worse than not sealing at all — so we make sure water has a way out first. See our drainage and sump pump pages for how that works.
Our Process
Step 1 — Free inspection. We crawl the space, take photos, and measure moisture in the wood and the air. We check for standing water, mold, rotted wood, and failing insulation.
Step 2 — Written estimate. You see the photos and get an itemized price for the full system. If you only need part of it, we will say so.
Step 3 — Prep and cleanup. We remove old insulation, debris, and any moldy material. If there is mold, we remediate it before sealing — trapping mold inside a sealed space is a mistake we will not make.
Step 4 — Drainage and repairs. If water gets in, we install drainage and a sump pump now. If joists or subflooring are rotted, we repair them now, while everything is open and easy to reach.
Step 5 — Seal and line. We seal the vents, gaps, and door. Then we lay the liner wall to wall and up the walls, sealing every seam.
Step 6 — Dehumidify and verify. We install the dehumidifier, set it, and verify the space is drying out. We walk you through the finished work and how to check on it.
What Encapsulation Fixes
Homeowners call us about symptoms. Encapsulation fixes the cause. Musty smells in the house fade because the damp air rising into your rooms is gone. Floors feel warmer in winter because the space below them is no longer an icebox. Hardwood floors stop cupping because the moisture feeding them from below is cut off. Energy bills often drop because your heating and cooling system is no longer fighting damp air.
It also protects the structure. Wood that stays dry does not rot. Joists and beams that are not rotting do not need expensive structural repairs later. Termites love damp wood, so a dry crawl space is less inviting to them too. And stored items — holiday boxes, tools, keepsakes — survive instead of growing mold.
What Encapsulation Does Not Do
Honest talk. Encapsulation will not fix a plumbing leak — if a pipe is dripping, that has to be repaired first. It will not fix water pouring in from bad grading outside — we may need to address drainage or send you to a grading contractor. And it is not a one-day bandage: a proper job takes several days and costs real money, because it is real construction work under your house. Anyone offering to "encapsulate" your crawl space in an afternoon with thin plastic is selling you a future problem.
Keeping It Working
An encapsulated crawl space is low maintenance, not no maintenance. Check the dehumidifier's drain line once or twice a year to make sure it flows. Peek in once a year to confirm everything looks dry. Change or clean the dehumidifier filter as directed. That is about it. The liner itself should last for decades — there is nothing down there to wear it out once the space is sealed and dry.
Every project is different — contact us for a free written estimate.
Call (301) 679-9193 or send the form below for your free crawl space inspection.