This study characterises the original construction materials (building stones and mortars)
of a collapsed two-storey colonnaded structure in the Ismail Mandani house, located in the old city
centre of Doha (Qatar). Results were drawn based on interpretation and integration of historical,
in situ observations and analytical data. The mortars and stones were characterised following
a multidisciplinary approach, combining macroscopic observation with petrographic microscopy,
mineralogical analysis (X-ray diffraction) and elemental analysis (handheld X-ray fluorescence) of
samples. Moreover, hydric properties, ultrasonic pulse velocity and colour of representative samples
of the house were studied. The results revealed the use of two types of stones and three different types
of gypsum mortars. The original construction materials came from nearby coastal stones. Gypsum
of the most used mortar had a calcination temperature between 120 and 160 ◦C and its colour was
produced by lumps with higher Fe content. The materials’ effective porosity and water absorption
were high, and their ultrasonic pulse velocity was low. These petrophysical results indicated they
had low quality for construction purposes. The composition and colour of the original construction
materials were quantified, which will allow the reproduction of their aesthetic characteristics and
improvement of their quality in future reconstruction works
