Redwood trees are staining my flagstone patio


We just finished a backyard remodel a month ago and now our redwood trees are dropping brown/purple sap that seems to be staining the Ct. Blue stone flagstone that we just installed.

Is there any way to get it off and prevent it from staining again next year? I have tried scrubbing it, pressure washing it and simple green so far. Nothing has worked.



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good insight
by: David

Thanks M.D. for the comment.

It's good to get a different perspective.

Residue from flowers or cones possibly
by: M. D. Vaden Redwood Photography

The color may not be sap, unless you can see it oozing.

But redwood tree flowers, cones or pollen, can be very colored. If it washes-off, it could look like some sort of colored sap.

Not sure if that's your situation. But keep it in mind. The color is powerful.

sap on flagstone
by: Richard

I'm like Dave...pressure washing should have helped somewhat...We use a product cleaner from Surebond.
SB442 General Stain Remover is a concentrated, non-acid degreaser and general purpose cleaner for use on concrete and stone products. It does not contain harsh acids. Its unique clean rinse technology lifting power allows residue to be quickly and easily rinsed away with a high or low pressure water sprayer.

After cleaning we recommend SB5000 stain blocking sealer. It is a water based, penetrating,low VOC sealer that provides an invisible, durable barrier that blocks water, oil, and stains. The finish has a natural look.

tough sap
by: David

I'm surprised that the pressure washing didn't help.

You need to seal your stone to prevent future staining.

You should give Prosoco a call at 1-800-255-4255 and see if they have a chemical that can remove the sap. Also ask them about a proper sealer for sap. They're the company my dad refers to for questions like yours.

Great luck with your project!


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