Stone ornament restoration

Sumner Road, Chelsea

We have been asked to restore a missing stone ornament from a portico column and to reinforce another one which was about to come off as well.

 Broken off stone ornamentSeverely cracked stone ornament

 

To re-create the stonework we used for a sample one of the other columns which was in best condition. Despite we chose the best ornament for a sample, the multiple layers of paint over the years have deshaped its corners and in order to achive the original look we had to carry out the restoration in three stages:

 

  • Take a mould from the sample ornament and manufacture a copy using soft plaster.
  • Restore the original shape of the ornament on the soft plaster copy.
  • Take a mould from the restored plaster copy to lay the final stonework.

Take mould by applying layers of silicone.

Silicone mould

Making the silicone mould from the matching column took about a day. The first three layers are done with a liquid silicone and brush to allow us to take even the finest details of the ornament, then another two layers of thicker silicone were applied using a putty knife. Finally we wrapped the entire silicone mould with epoxy pads to create a box not allowing the silicone to bend.

 

Use soft plaster for the first mould to allow easier modelling. Soft mould to allow us to shape and improve the look of the stonework.

Using the first silicone mould, we created an ornamnet using soft plaster to allow us to easily work on it and recreate the original shape of the ornamnet. Using a paint brush, I've applied around three - four layers of soft plaster with thickness of about 5 mm. Then I've built up with a thicker plaster and left it to harden for a day.

Soft mould to allow us to shape and improve the look of the stonework.

Stonework ready to be installed

Once the soft plaster ornament was out of the silicone mould, we no longer needed this mould as it was carrying the deformations from painting and weathering over the years. Using masonry knifes and files we modelled the plaster ornament to the original look. When we were happy with the ornament, we repeated the process of applying silicone to create the final mould which we used to lay the final stone mortar.

The new stonework was installed with reinforced bars reaching to the centre of the column to provide the adequate strenght. The cracked ornament was drilled through and a stainless steel bar was inserted with epoxy resin to prevent further cracking and ensure it does not come off. Finally the cracks were filled in and the new ornament was blended with the original stonework.

Installed stone ornament Installed stone ornament Finished stonework