The common problems are humidity that never comes down, water trapped under the liner, seams and terminations that release, hidden plumbing leaks and condensation on ductwork. Almost all of them trace to one of two shortcuts: sealing before the water was handled, or sealing without conditioning.
Humidity that never reaches target
Usually an undersized dehumidifier, or a space that is not actually sealed — most often at the access door, which is the largest remaining opening once the vents are done.
Check the door seal and the vent detailing before assuming the unit is at fault.
Water under the liner
The classic outcome of encapsulating a crawl space that still takes groundwater. The water has nowhere to evaporate to, and the first symptom is usually an odour months later.
The fix is drainage, which now means lifting the liner along the perimeter — considerably more expensive than doing it in the right order.
Seams and terminations letting go
Tape applied to dusty block releases. Liner that was not mechanically fastened at the perimeter slides down. Piers left unwrapped let moisture track up around them.
These are workmanship failures rather than design ones, and they concentrate at the edges rather than in the field of the liner.
Hidden leaks and duct condensation
A sealed liner hides a slow plumbing leak that would have been visible on open ground. Inspect twice a year.
Uninsulated ductwork in a crawl space that is now semi-conditioned can sweat. If ducts run down there, they should be sealed and insulated as part of the work.
The bottom line
Most encapsulation problems are installation problems. Water first, conditioning always, and terminations done properly — get those right and the failure list mostly disappears.
For a number against your own crawl space, use the cost estimator, or call (910) 886-2018 and we will come and measure it.