Preserver has been formulated to seal unfinished wood,old wood, terra cotta, cement, brick, concrete before painting.  A coat keeps the internal moisture in and the external moisture out. This great product is also used as an isolation barrier, to protect the under layer of paint from added glaze coats over it. No VOC's, no odor, non toxic, water based, can be applied with a brush, sponge, cloth or roller.  Conforms to ASTM D6886.  Made in America.  Keep From Freezing.