All existing timber works were heavily treated with several layers of ta chi - an organic stain used for protective and decorative purposes. The ta chi was brought in specially from China. Before being used, it had to be strained to remove any unwanted particles. Coloured powder, usually in shades of red and black can be added to the ta chi mixture to obtain certain tones. Traditionally, Ta Chi mixed with powdered lime also served as a timber filler.

All new timber components would be given several layers of Ta Chi. First, existing timber was sanded down and ta chi reapplied with a spatula or, in difficult areas, by hand.

Ta Chi also provided the base for gold leaf gilding. Existing images were traced back onto the beam and ta chi applied to the area to be gilded.