Green Oak Frame - Tannin Removal

• Oak contains ochre coloured tannins which are water soluble and wash off in the rain.
• These have stained the masonry underneath the oak frame.
• It's best to wait for around a year for all the tannins to leach out of the green oak before attempting to clean the masonry.
• The ochre tannins may also wash off the masonry over the course of this period. After which the remaining tannins can washed off.

To clean tannin stains from masonry, you can try washing with water and scrubbing with a brush, or using a tannin stain remover. For severe stains, you may need to repeat the process. 

Steps

1.  Clean with detergent: Use a quality detergent to remove any added substances. Avoid soap, which can make the stains harder to remove.
2.  Apply tannin stain remover: Use an acid-based tannin stain remover to dissolve the tannin.
3. Scrub: Scrub the stain with a brush or broom. 
4.  Rinse: Rinse the area thoroughly with clean water.
5. Repeat: Repeat the process if necessary.