Bağdadi (lath and plaster)

Bağdadi is the Turkish lath-and-plaster technique for walls and ceilings: thin timber laths are nailed to both faces of a frame of posts and rails with small gaps between them, and the laths are then plastered. The plaster pushes into the gaps and keys onto the laths. Traditionally it is lime or gypsum based, with fibres such as animal hair, straw or hemp added to limit cracking. Unlike hımış, the spaces inside the frame are left empty instead of being filled with masonry.

Bağdadi in the Turkish house

Bağdadi is common on the upper floors of the Turkish house, in internal partitions and in ceilings. Being very light, it reduces the load on projecting upper floors and bay windows, and gives large rooms with thin walls. The same technique appears on ceilings and on eaves soffits. The price of lightness is poorer thermal and acoustic insulation and lower fire resistance, so in houses with bağdadi walls keeping the plaster intact is part of protecting the building, not just a matter of finish.

Bağdadi in survey and restoration

Survey sections show bağdadi walls together with their frame and lath layer, and areas of lost plaster are a good opportunity to read lath spacing and frame layout. The main problems are plaster detaching from the laths and bulging, laths loosening as their nails corrode, and frame rot caused by damp. Sound plaster is left in place and secured at its edges, while missing areas are filled with a fibred lime or gypsum plaster similar to the original. Cement-based plaster is heavy and rigid and does not move with timber, so it soon cracks and comes away.