Timber lacing (hatıl)

Timber lacing, known in Turkish as hatıl, is a horizontal band built into a stone or brick wall at regular intervals. In traditional buildings it is usually timber: two beams are laid parallel to the inner and outer faces of the wall, linked by short cross pieces, and the space between them is filled with walling. The wall is thus girdled by a horizontal frame every few courses. In modern construction reinforced concrete bond beams do the same job.

Its role in the building

Lacing noticeably improves the behaviour of rubble and mud-brick walls in particular:

• It resists the tensile forces that stone and mortar handle poorly, making it harder for the wall to split and disintegrate.
• It spreads loads over a wider area and reduces the effect of local settlement.
• It helps the wall rise straight and level; sill, lintel and floor levels often line up with the lacing.

In traditional houses in earthquake-prone regions, laced walls are regarded as a seismic measure passed down through generations of local builders.

Timber lacing in survey and restoration

Lacing is often hidden under render; in a survey its position is read from areas of lost plaster, traces on the wall face and small probes, and it should always appear in the sections. Moisture is its main enemy: roof and gutter failures, rising damp and impermeable renders lead to rot. A rotten beam leaves a void inside the wall, and the masonry above begins to crack and, in places, collapse. Repair replaces decayed sections with timber of the same section and a suitable species, rebuilding the surrounding masonry in lime-based mortar. Showing the lacing pattern in a 3D model is a clear way to explain the areas of intervention in a restoration project.