Pressure treated wood is created using chemicals and other materials that need to properly cure prior to applying a waterproofing sealer or other coating. If a sealer or coating is applied to pressure treated wood before it has cured, it can result in peeling, cracking, bubbling and other adhesion problems. In the case of SEAL-ONCE products, if the they are applied too soon, the chemicals in the wood will prevent penetration, which will inhibit the product’s ability to protect the wood. The best way to determine if pressure treated wood has cured, and is ready for SEAL-ONCE products to be applied, is to sprinkle water on the surface to see if it soaks in or pools. If the water soaks in, the wood has cured and is ready for SEAL-ONCE to be applied. If it pools or forms droplets, you need to wait longer before applying SEAL-ONCE.