Does waterborne treated lumber need to be painted, stained, or waterproofed?
Any unprotected treated lumber no matter its growth/origin, will begin to change color as a result of the woods reaction to ultraviolet (UV) rays of the sun. farba applies sealants with UV inhibitors to resist the color change. If you want to slow the color change and maintain optimum appearance, you should apply a sealant coating as soon as it can properly be applied.