Dehumidifiers & Sealed Crawlspaces
Dehumidifying the air will help to protect your remediation investment by controlling present and future moisture levels in the crawlspace. This will help to inhibit future fungal growth from occurring. Our dehumidifiers are powerful commercial units that are specifically designed for your specific crawlspace size and deliver quiet, energy efficient service. We do not install dehumidifiers that you can purchase at the big box stores. These simply cannot handle the volume necessary.
We recommend dehumidifiers over “conditioned” crawlspaces. Conditioned crawlspaces are not really conditioned because NC code stipulates that crawlspace air cannot be introduced to the HVAC system, where the conditioning takes place. This means that you are only regulating temperature via a small outlet placed into the ductwork. Then you cross your fingers! Dehumidification actively pulls the moisture out of the air and surrounding substrates to keep your crawlspace dry and mold free year round.
A dehumidifier should be as centrally located as possible within the space. A GFCI outlet is required. The dehumidifier is not attached to the floor system to reduce noise/vibration transfer into the living space. The condensate line, if possible, should be its own separate line and not “tie into” other condensate lines. It should extend out the foundation wall and away from the structure. The line should not utilize the positive/foundation drain as a means of egress. Sometimes it is necessary to utilize a condensate pump due to location. This is acceptable as long as the water is pumped out of the crawlspace. If a sump is installed, the condensate line can terminate at the sump. Ducting of the dehumidifier is an option in situations where there is a separate area requiring dehumidified air such as an addition. All of the foundation vents, and foundation penetrations must be sealed with rigid sheet foam and/or expanding fire foam. The access door must be treated like an exterior door and sealed around the perimeter. Access holes to voids underneath porches should be sealed with rigid sheet foam and expanding foam. A drain should be installed in the vapor barrier at the positive drain.
Dehumidifier installs afford the owner the opportunity for a warranty!
Some crawlspaces are good candidates for sealing. That is, extending a poly barrier up the wall. This is usually recommended when there is a lot of water showing up from outside on the inside of the crawlspace. If this is the case, you will generally see a lot of moisture staining and/or efflorescence. Efflorescence is the white powdery stuff you see on your foundation block on the interior side. This is caused by water pressure on the outside of the wall pushing the minerals in the block out the other side. It is sometimes mistaken for mold. Please be aware that if you have a lot of water showing up on the inside of the crawlspace, simply running poly up the walls does not make it go away. It only hides it. We strongly recommend appropriate drainage measures be put in place prior to sealing. Once you have the poly up the walls, you can’t see what’s going on anymore and you will not realize you have a problem until you have a water bed! We have floated around on many of these much to the dismay of the homeowner who paid a company big money to seal the crawlspace but were not told the ramifications of doing so. Be informed!