Restoration wall mosaic


In October 2007 our restoration studio was approached by a member of the art committee enquiring whether we had time for a commission to restore a glass wall mosaic, which had been discovered behind a facing wall during renovation work on the I.S.H. school building.

The wall mosaic proved to have been damaged by drill holes at 60 centimetre intervals during mounting of the facing wall. Altogether 33 holes were detected, caused by the masonry plugs used to secure the wall.

In some cases large glass splinters were missing around the drill holes as a result of hammer drilling. Hammer drilling had also left 45 holes in the wall area surrounding the mosaic. The mosaic had been partially (20x20cm) smeared with cement during earlier renovation work.

Another section was smeared with latex paint, presumably during earlier painting of the ceiling (latex stain of ca. 3 m2, mainly in the grout joints). During cleaning of the background wall the original colour showed through as a light whitish blue. After our quotation had been accepted the actual restoration work began.

The restoration

The entire grey-brown background wall of 4×6 metres was degreased and lightly sanded, after which the holes were filled with filler (Alabastine). The entire wall mosaic was cleaned (non-iogenic soap) and all holes pre-filled to their full depth with filler (Alabastine). The entire background wall was repainted in the original white-blue colour (after various colour tests). (Note: removing the grey-brown paint (oil-based) to return to the original white-blue coat was not feasible on grounds of both cost and time. The cement smear on the mosaic was cleaned (demineralised water and acetic acid, scouring sponge) and the latex paint removed, (scalpel and di-acetone/ethanol, glass-paper).

The holes in the wall mosaic were pretreated (with Paraloid dissolved in ethanol/acetone, 10%). The holes were then filled with various colours of a pre-coloured 2-component composite (polyester compound, pu colour tubes, Polyservice, Amsterdam).

At last the filled holes were touched up (using Kremer pigments in Mowilith, dissolved in ethanol/acetone mixture) in the appropriate colours, and then given a glasslike gloss finishing coat (Acrylic varnish, W&N).

In one place, a “dot” of a red relief form was completely lost, but as a form readable. This section has been restored with pieces of new cathedral glass, which are brought to the right in the back. And then glued (tile-glue). Due to the different material, this restoration can be traced as a restoration.

The upstanding edges surrounding the mosaic were more or less “painted” in the past overlap of the back wall. We have returned the original black-gray cement color of the joint cement as a “color sand”, to make the original relief form of the joint cement better straightforward. The restoration was fascinating and gave a lot of insight into this wall relief. The end result is highly appreciated by all concerned.

Restauratie Atelier Picard is lid van de beroepsvereniging Restauratoren Nederland