Tenting on historic tiled floors

Berenice Humphreys <berenicehumphreys<-a t->clivedenconservation< . >com> writes

>We have had a run of enquiries lately on Edwardian and Victorian
>tiled floors where a 'tenting' phenomenon has occurred.  Entire
>sections of flooring are damaged when delamination occurs between
>the tile and adhesive, and the substrate. ...

This problem relates to the growth of low fired ceramic over time
and is most often discussed in relation to brick growth.  Fired
ceramic will naturally expand by up to 2.4% over time.  The first
1/3 of this expansion occurs in the first 6 months, the next third
over 5 years and the rest over the remaining century or so.  Floor
tiles, in my experience, are laid with very thin joints and often
are touching despite having a visible joint.  Any slight expansion
across a floor will cause bowing as you describe and there is only
one direction this can go.  Other factors such as thermal expansion
may contribute but the natural dimensional increase in such a
tightly laid system inevitably leads to this phenomenon.  You will
find ample literature if you search on brick growth.  I am assuming
you are referring to Minton type floor tiles and not highly glazed
types.

Andrew Thorn


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                  Conservation DistList Instance 28:20
                Distributed: Saturday, October 18, 2014
                       Message Id: cdl-28-20-002
                                  ***