The Qa’a is a roofed reception room found in the domestic architecture of affluent residences of the Islamic world. It is the most common hall type in the medieval Islamic domestic architecture. The plan of a qa’a may be inspired by the four-iwan, cruciform-shaped plan of religious buildings. They were used to welcome male guests, where they would sit on the raised platform.

Composition
Qa’as are found in domestic houses of wealthy people, e.g. merchants or local political figures. They can be situated on the ground floors or on the first floors. Entrance to the qa’a is usually situated facing the semi-private courtyard of the house.

The qa’a can be described as a combination of a courtyard and iwan. The qa’a consists of a depressed central area (durqa’a) where guests would first enter the qa’a via an opening; and the raised sitting area (tazar) where the guests would take off their footwear and be seated on the diwan, a couch that is placed on the floor against the wall. The tazar is placed in a kind of iwan, a rectangular hall walled on three sides. Normally there are two iwans facing each other on the main axis of the qa’a, with wall recesses on the two remaining sides.

The durqa’a (literally “entry to the qa’a”) is the first area where the guests would enter into a qa’a via a main entrance. It is the central space of the qa’a. In a qa’a composition, the durqa’a is flanked with two tazars (raised sitting area) on the two sides of the durqa’a, or sometimes just one. The durqa’a is where a cooling fountain (fasqiya) may be installed, a typical feature in Islamic architecture which provides sound into the space.

The tazar is the raised sitting platform. They are located in the iwan. In the complete composition of the qa’a, there are two iwans flanking the durqa’a at the sides. The tazar is where the male guests would be seated, and then served food or coffee by the servants. In a few example, there is additional access that leads directly toward the tazar, usually this is a service access where the servants would enter to provide fruits or drinks. Recessed shelves are located on the wall on the sides of the tazar, this is where ceramic bowls, ewers, carved metal works, or books were displayed. The walls may also be decorated with Arabic calligraphy, usually of poetry, a dominant form of art in the Islamic world. Mashrabiyas are sometimes used to cover recesses on the side walls of the two iwans. Sometimes there’s also a decorative niche (masab), which is treated like a kind of niche found in mosques, with miniature muqarnas decorating the miniature ceiling of the niche.

The ceiling of the iwan is always lower than the ceiling of the durqa’a. In the earliest qa’as, the iwans are usually barrel-vaulted (e.g. the qa’a of al-Dardir House in Cairo). In a Mamluk qa’a, one of the iwan would have a windcatcher (malqaf or badhahanj) which brings in the breeze into the qa’a. The ceiling of the durqa’a is normally the tallest in the qa’a, often topped with a wooden hexagonal skylight (shukhsheikha) which provides light into the interior or equipped with a lantern.

Interior design
The qa’a is heavily decorated with vibrant colors and complex pattern. The design of the room is where the owner of the house can show off to the guests. They can be designed in different styles, depending on where the qa’a is located.

The wall of the qa’a is normally wooden panels of cypress, poplar, or mulberry. A qa’a in Ajami style would have the wooden walls layered with a gypsum mixture to create a raised patterned surface, decorated with metal leaf (e.g. tin, silver, or gold) and then painted and layered. The entire wall would then be varnished. Today the color of old qa’a walls would be low in saturation, but they were used to be extremely vibrant in color. Many newer domestic houses, e.g. those in Damascus, still have vibrant colors of green, blue, fuchsias and purples.

The floor is of cut inlaid stones.

Usage
The qa’a is one of many reception rooms featured in the domestic architecture found in Egyptian Ottoman and other Islamic worlds e.g. Syria. A qa’a is featured in affluent houses of a merchant or a local political figure. The place is where the owner of the house would have a meeting or greet his guests. The qa’a doesn’t have any fixed furniture and that it was seasonal. The qa’a is ideally located to the north side of the courtyard of a house, so that it could have taken advantage of the sun’s rays during winter when the sun would is at the lowest. If the qa’a is used for the summer, they would have the windcatcher to direct breeze into the room during summer time. The qa’a can also be used as a sleeping room. In that case, there will be a larger niche where bedding rolls and carpets would be placed to be used for sleeping.

ataba is a term to indicate a low zone, a term which is applied to the depressed durqa’a. If the guests of the house owner are not important, they are kept in the ataba. They are only allowed to enter into the tazar if they are guests of honor, where they would sit on the couches after taking off their footwears.

The tazar is a place where important guests would be seated. Here, they would be served fruits depending on the season, or drinks (e.g. coffee) or a hookah. Depending on how important the guests are, they would be seated toward the central part of the rear wall, where they could admire the glory of the qa’a.

Examples of qa’a
The qa’a room is found throughout the Islamic world, especially in Ottoman Egypt and Ottoman Syria. Below are lists of buildings with notable qa’a:

Bayt Al-Suhaymi in Cairo containts multiple qa’as facing its inner courtyard.
The Damascus Room is Qa’a kept in the Metropolitan Museum of Art in New York is a winter qa’a from Syria

Source From Wikipedia