It is houses that is the principal base of all kinds of Islamic buildings. By improving house types, Muslims have been developing religious, political, and economical architecture. The fact that the mosque representing Islamic architecture derives from the house of Muhammad in Madina shows this distinctly.
However, due to the broadness of the Islamic world, types of house are quite diverse in adapting to the climate and environment of each region. Although the most Islamic-looking one in the Middle East must be the courtyard-house type, it was only succeeded to from the long continued house form since before the birth of Islam, as I wrote in the chapter of Suhaymi House in Cairo, being not created by Islamic culture.

Underground house in Matmata

There are non-courtyard type houses in various parts of the Islamic world, such as cave dwellings as a quite primeval type, for example. As seen in cave houses in Cappadocia, a house consists of excavated rooms and a kitchen in a soft rock mountain. The reason that they are inhabited still now is they are cool in summer and walm in winter to live without electric appliances like air-conditioner.
There are cave dwellings in southern Tunisia, inheriting a tradition consecutive from the times of ancient Rome. A house consists of cave rooms around a dug down courtyard. The interior of the rooms are usually whitewashed and the main room's wall is often embellished with the dishes.
While in Turkey, which is mostly cold highlands, houses are not courtyard-type but wooden multistory-type covered with tiled roofs. The interior is focused on a fireplace like European houses.

 
Courtyards of Houses in Yazd & Aleppo

Be that as it may, the courtyard-type of subtropical zone is quite crucial as a prototype of various Islamic houses. The method of making a tropical house is to build walls, first of all, to surround the site, inside which are erected needed rooms one by one in the wake of the growth of the family to complete the courtyard. What people wanted in a city was a maximum peacefulness for a private life. For that, a long approach was often laid between the street and courtyard.

Such an inward-looking house is closed to outside by impassive walls, concentrating all furnishings for comfortableness and consideration for beauty upon the courtyard, and all going in and out the rooms and their ventilation and lighting are taken through the courtyard.
In Persian and Syrian houses, a northern aspect Iwan is prepared in front of the courtyard, being also called Aywan or Eyvan, a half-outside space with wooden columns, near to a Talar for palaces. A large residence has a public and private courtyard with a Iwan or Eyvan respectively and also one for livestock.

Khujaev House in Bukhara

PLAN of Khujaev House

Setting a water basin with a fountain in a garden and adding plants to it, which gets close to the image of paradise for Middle East people. A mansion like Khujaev House with a two story-high large Eyvan facing a courtyard looks like a palace. Cities are crowded with multi-story courtyard houses. Through the rule of avoiding making windows looking into neighboring houses, external walls of a house become more impassive.
Inside a house, functions are not strictly determined for rooms, letting the family to move from room to room according to a season or time in a day, using any room for living, dining, or sleeping. To make it easy, they do not put many furniture in each room and live without shoes, sitting not on a chair but directly on the floor like in Japanese traditional houses. Instead of Japanese Tatami, they developed carpet industry.

A Bedroom of Jauli House in Sfax

A special disposition of Islamic house is the separation of Saramlic (space for men) and Haramlic (space for women). It derives from a custom that piety Muslimas (Islamic women) must not to show their faces and bodies to men other than their families. The Turkish word 'Harem', with the same roots of Haramlic, is often translated to seraglio, but actually means the women's part, or family space of a house at large.
That is to say, the public part of a house receivable guests is men's space, and the family space where strange men cannot enter is 'Harem'. Large residences often have separate approaches or respective staircase to each upper floor.

( In the chapter 4 of "Architecture of Islam", 2006 )