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Bob M

wrote:

Bob M wrote:
I have a natural cedar deck that I pressure washed and then stained with
semi-solid this past spring. Came out quite nice.

A good portion of this deck in under a maple tree on one side and oak
trees
on the other. Over the past few months, even though I kept blowing the
leaves off the deck, there has been a buildup of a black residue on the
deck. I tried scrubbing this with a soap and water solution without
success.

Is the black color simply darkening, or is there something gummy/stick?
If it is sap from trees, mineral spirits and stiff brush should take
most of it off. If it is simply staining from tannin in leaves, it
probably won't come off (unless bleach works on it).

Can anyone recommend a solution that will soften/emulsify this residue
hopefully without harming the stain below it?

Any advice greatly appreciated.

B

Why do people use good wood like cedar and then paint the stuff? Kind
of like buying gold jewelry and having it tin plated )

When the desk was first constructed to replace on old pressure treated one,
the white cedar was stained with Sikkens Cetol CRD. For the first year the
deck look like a piece of fine furniture. And that's one reason why we
selected cedar in addition to its longevity properties. However, starting
the 2nd spring, it severely darkened and bubbled in places to the point
where we actually had the wood rep and the sikkens rep both visit at the
same time. Of course they both pointed fingers at one another. Bottom
line, we were stuck so the only thing I could do was pressure wash the deck
to remove as much of the bubbling/peeling/residue and possible, let it dry
for a couple of weeks then apply a semi transparent stain this past spring.
It looked pretty good until the dark residue started this fall.

One responder mentioned that it might be mildew which I could remove with a
weak bleach solution. I haven't tried that yet with the fall leave tasks,
but now that that's done, the bleach is my next job.

I hope I answered you question about covering up nice wood. Even though I
did my homework on this new deck and selected materials and finishes based
on the results, after the honeymoon the look went away.

Later - Bob