What is Sapstain - Blue Stain?

The term sapstain and blue stain is used in manyPreventing Sapstain
articles concerning rot and wood preservation. OneTo prevent sapstain from discoloring the lumber and
should understand this term as a first step into prevent further degradation through decay, many
understanding wood degradation and rot.mills will dip the product into a fungicide to deter mold
What is Sapstain?from attacking the lumber. This is particularly
A tree consists of many parts, but for this shortimportant in the humid areas of the United States
treatise two terms, heart wood (physiologically deadand its use is highly recommended for high quality,
wood located near the center of the tree) and sapvaluable lumber.
wood, which are located on the outer periphery ofLumber which has a high propensity of sapstain will
the tree (physiologically active) will suffice. The sapnot take a finish evenly. The area which has the sap-
wood carries water and nutrients up though the treestain will absorb wood finishes more than unaffected
and thus is a perfect environment for sapstainareas. Thus, when finishing a piece of lumber so
growth.infected, one will have to use a number of wood
When a board or timber is cut from a log, moldfinish coats to even out the look. For high quality
spores can come in contact with the nutrient richproducts such as furniture or mouldings, the lumber
wood with its inherent high moisture content andinfected with sapstain is discarded.
they begin to multiply and spread over the face ofIf one is installing wood which has mildew present, it
the lumber.should be washed thoroughly before applying any
As they spread they create a stain which is normallytype of finish. We are talking about a surface coating
blue, but can actually be different colors. Throughoutof mildew, not a stain that has penetrated deep into
the years I have seen not only blue, but also black,the wood. Use a mixture of three quarts of water,
red and yellow.one quart of household bleach, and 1/4 cup of liquid
If this mold/stain is not checked, it can penetrate intodishwasher detergent which does not contain
the wood with tendrils and take the infection deepammonia. Never mix bleach and ammonia as it will
into the lumber or timbers. They will eventually emitgive off hazardous fumes. This formulation can be
enzymes which will break down the wood and thensprayed on using a pump sprayer. After 15 to 30
you have the start of serious decay. We are talkingminutes, it can be washed off using a power washer.
about lumber which is wet (unseasoned) and in aRemember that once the stain goes deep into the
nutrient rich environment. Many people talk of drywood, it cannot be removed with bleach or any
rot; but in reality there is no such thing. This is aother product. It is there to stay. Always remember
misnomer. since wood needs to be between 30 andnot to play chemist and experiment by mixing various
60-percent moisture content for it to begin thechemicals as they could give off hazardous
decay cycle.fumes...and more!