Noticed Green Spots on Your Wooden Product? Don’t Worry – It’s Not Mold!

Why Do Green Spots Appear?

Treated wood surfaces can sometimes show dark patches or green-blue dots, especially around knots or denser grain areas. These are known as salt efflorescence, and while they may look unfamiliar, they’re a sign of deep and thorough impregnation.

At Jagram, we use Tanalith E, a premium wood preservative from the trusted UK company Lonza Wood Protection.
This treatment protects wood against fungi and bacteria that cause rot. In order to penetrate deeply, the preservative is fully absorbed into the wood. During drying, greenish or bluish marks can rise to the surface — proof that the treatment has reached deep into the structure.

As long as the wood does not come into direct contact with soil, it will remain resistant to decay for at least 10 years.

How to Deal with the Spots?

These marks may be considered unsightly at first, but the good news is:
They’re completely harmless and will naturally fade or wash away within 1 to 2 months due to rain and moisture in the air.

Want to speed up the process?
You can clean the surface gently using:

• A pressure washer, or

• Water and a stiff brush (e.g. scrubbing brush or deck brush)

Do not sand the surface or try to remove the spots mechanically.
This can damage the wood surface and reduce the effectiveness of the protective treatment.

Please note:
These marks are a normal result of the impregnation process and are not considered a product defect or valid reason for complaint.