Are you experiencing the appearance of brown spots on your deck? Perhaps circular stains that appeared after you stained or painted the wood? If so, you are not alone and there is a solution for the problem. Circular stains that look similar to coffee rings often come through a light colored stain or paint after the coat dries. This problem stumps deck refinishes so they usually apply another coat of paint. However, regardless of how many coats you apply, the sap will continue to show. Unfortunately, more paint is not the permanent fix you are hoping for.
What Causes the Brown Rings?
The answer is sap. Sap is the lifeblood of the tree and can be trapped in knots at the time the wood is cut. Most customers assume pressure treated wood is free of sap, but that is a misconception. Older white pine was air dried after being cut, which means the sap has the potential to seep out of the wood, especially during a sanding and restoration process. It’s no coincidence that the stain rings are only found where the knots are on each board.
How Can You Fix Brown Spots on Your Deck?
The good news is that newer pine is kiln dried after being cut, causing the sap to crystallize. Crystallized sap will not leak through your wood. If you are dealing with older, air dried pine there is still a solution that with an additional step can permanently prevent the marks. The product is called knotting solution, and if brushed over all of the wood’s knots after sanding, this will dry and seal the sap, allowing you to apply your light colored stain without brown rings coming through.