relaying a 19th Century tiled floor

We've just spent the past three months on our hands and knees in the Great Synagogue in Sydney.  And the result is that the tiled floor to the central portion of the Synagogue is now fully functional again. 

Laid with geometric and encaustic ceramic tiles on a cement mortar bed over a timber-framed floor in 1885, the floor had seen 125 years of services. 

Unsurprisingly, particularly given the structural alterations carried out beneath the Synagogue in the 1950s, some areas of the ceramic tiling were badly disrupted, with tiles cracked, loose and missing.

Over the past few years, we have been working with Peter Phillips of Orwell & Peter Phillips, Honorary Architect to the Great Synagogue, and Simon Wiltshier, structural engineer from Hughes Trueman, to investigate the problem and develop an appropriate conservation solution.

The recent works were undertaken in two phases.  First, structural interventions were undertaken to provide additional support to the timber floor structure.  This work was completed from beneath the floor without requiring any disruption within the Synagogue.  The second phase saw us progressively lifting and relaying the ceramic tiles.

We carried out the work so that each Friday afternoon we could vacate the Synagogue, leaving only a small area of the floor and a limited number of pews discreetly barricaded off.  Each Monday morning, we would open up new areas ready for the week's work.  We also stopped work several times each week during scheduled tours of the Great Synagogue.

We had previously procured replacement geometric and encaustic ceramic tiles for those missing or broken or excessively worn.  These replacement tiles came from Maw & Co, the English company which had manufactured the original tiles installed in 1885.  Needless to say, the limited number of replacements (5-10% of the total) and our work to lift and relay the floor cost rather more than the complete cost of the original tiles - the Great Synagogue's records show that the tiles originally cost £344/1/4 (three hundred and forty four pounds, one shilling and four pence), whilst the tiling cost £100.

We also worked with the specialist supplier of conservation materials, Westox, to develop a cementitious mortar that would be as close as possible to the original mix used to lay the tiles.  The composition of Portland cement has changed significantly since 1878, and it is now much stronger and chemically different to then.  The mix we developed used a combination of modern Portland cement and pozzolans to reduce the strength and shift the composition and characteristics of the mortar back closer to the 1870s Portland cement based mix in the original floor.

Other challenges included:

• how to integrate the replacement tiles with the original tiles
• resolving variations in the dimensional tolerances of the tiles and original joint widths
• lifting and refixing the timber pews

We successfully relaid the floor in the time available to us, and based on our recent post-completion inspection, the floor stood up to all that the large wedding held a few days after we finished work could throw at it ... including breaking glass!

David West
International Conservation Services