The Great mosque of al-Sudus is situated within a fortified town enclosure, and shares its southern wall with this fortification. Due to the very dense urban fabric of al-Sudus, only this southern wall of the mosque is exposed. The mosque was built of mud brick, as were the neighboring buildings. It has two floors, with a courtyard on the second floor. Following an exodus from the town to a nearby village, the mosque is the only building within the walls of al-Sudus that is still in use.
The mosque is accessed through a door in the south wall that leads to the first floor prayer hall. Its roof is supported by three rows of columns that run parallel to the qibla wall on the west. An internal staircase leads to a second prayer hall above the lower one that opens onto a courtyard to the east. The columns in the first floor prayer hall support three arcades of triangular arches, which in turn support the upper prayer hall. Below the saw-toothed column capitals, small in-situ projecting shelves hold copies of the Quran. On the first floor, back supports for worshippers project from the floor between columns. A deep niche in the center of the qibla wall, divided in two by a column supporting two triangular arches, contains two sub-spaces for the mihrab and the minbar. The minbar is situated to the left of the mihrab and has a two-stepped platform. To the left of the minbar, the niche surface is pierced by a big and a small ventilation window. To the right of the mihrab on the qibla wall, a door allows the imam easy access to the minbar.
The mosque is undecorated on the exterior; however, its interior columns, their capitals, and the profiles of the arches are highlighted with white plaster. The lower part of the qibla wall is also plastered white; this plaster wraps around the imam's door and extends to the mihrab and minbar niche. Above the qibla niche, an Arabic inscription illustrates the Fatiha.
The minaret is located on the northern wall of the mosque and is accessed through a door from the courtyard. The minaret is particular to the Najd area in Saudi Arabia; it has no balcony, but has a platform within the shaft at the end of the staircase, used to deliver the call to prayer. The shaft is also used to access the roof of the second prayer hall via a staircase that wraps around it. The roof has a third mihrab and minbar situated in a niche aligned with those on the lower two floors.
Sources:
King, G.R.D. The Historical Mosques of Saudi Arabia, 146-149. London; New York: Longman, 1986.
King, Geoffrey. The Traditional Architecture of Saudi Arabia, 154-156. London: I.B. Tauris, 1998.