Dehumidifiers are designed to regulate the amount of moisture that is in the air of a given space.

When the water evaporates from the screed the air becomes saturated, it is unable to carry any more water and subsequently the screed cannot become any drier.

Dehumidifiers remove moisture from the air and recirculate dry air back over the screed, enabling further moisture removal from the screed. The dehumidification process encourages water out if the screed faster than natural drying as there is a forced extraction.