The gold dado or ‘girdle’ is terracotta, which has also been used for the altar, corbels and arched surrounds to the doorways. Most of the relief decoration was made from panels of layers of wire mesh and gesso and painted in tempera extending beyond the vaults up to the centre of the dome. Mary Watts had received guidance on the art of ‘gesso duro’ from the assistant to Walter Crane.
From its silver roots on the rippling sea bed, the Tree of Life grows through the golden girdle of the Trinity, spreading its all-embracing branches and bunches of grapes against the light of heaven. Flowers (a daffodil, arum, lily, primrose painted by the children of Compton) are intertwined in the roots above the girdle.
Haunting pairs of winged messengers encircle the walls, six red and green feathered cherubim to each panel. They each hold two Art Nouveau medallions. The detailed description of these medallions is given in Veronica Franklin Gould’s guide to Watts Chapel. Clothed in the crimson colour of love and life, raising her hands in blessing, a seraph stands above the cherubim at the top of the Tree in each panel. On the reredos (behind the alter) is Watts's own oil painting, a small version of The All-Pervading, completed only three months before he died. The gesso work was just completed when Watt’s altar picture was hung, in April 1904. A month later, he followed his wife up to the Chapel. ‘He had not before realised what I had aspired to,’ she noted, ‘in the matter of this glorified wallpaper.’
Mrs. Watts apologized for her extensive use of Symbolism, in case it appeared either too overpowering or too trivial for serious contemplation. On 1st July 1904, Watts died. Mrs. Watts placed her husband’s ashes in the gessoed casket she had made two years earlier and set it on the central pedestal of their Chapel. Her own terracotta candlesticks and wreaths of laurel, lilies and bay, lay in front of the altar.