is a vapor barrier neccesary for a custom wine cellar in your home?

Answer 1

A vapor barrier may be necessary to prevent condensation and mold growth inside the wine cellar.

Water vapor moves from higher to lower areas of concentration in nature's attempt to keep the universe in equilibrium. Because warm air can hold more moisture than cool air, your wine cellar will be on the receiving end of the moisture train. Once inside the cooler environment of a wine cellar, humid air looks for places to dump excess moisture. Objects cooler than the dew point of the air will become covered with condensation.

Install the moisture barrier on the outer side of the wine cellar to prevent the incoming moisture from reaching cool surfaces where liquid water can condense.

Answer 2

if you want to control the humidity, yes but if you keep the temperature constant thats all that's really needed. humidity effects the corks sometimes only if they are not sealed