At the end of 2007, we were asked, by the Social Fund, to restore the mosque of Al Ashrafiya in Ta’izz erected in the fifteenth century AD.
The paintings basis was realizzed with a lime and various kind of aggregates plaster, applied on a brick masonry and mortar support with mortar. The stratigraphic sequences of the plaster is not possible to distinguish because of the local traditional technique of mural painting called qadad.
This technique involves the application of a layer of plaster with a particle size of coarse aggregates, repeatedly beaten with a stone cutting. The subsequent drafting of the plaster, compose by a more thin aggregate, is constantly beat. This process causes the penetration of the plaster’s components, so the it is presented as a single layer extremely hard and solid, further refined and smoothed with a flat stone to polish the surface.
The degradation causes can be attributed to a number of factors. The combined action of these following phenomenon had greatly exacerbated it:
I.I seismic movements
II. Geological instability
III. The rainwater from the roof associated to physical, but mostly chemical, damages
IV. anthropogenic degradation
After a carefull observation of the conservation status of the mosque, was initiated a work of restoration, wich includes the consolidation of the walls, and the restoration of the wall paintings.
The reintegration of the many gaps of the gypsum ornaments was a very delicate stage of work and required specialized Yemeni craftsmen skills.