The Fatimid Caliphate in Egypt, specifically?

Most "regular" people were poor and probably lived in houses of one to two rooms, or rent part of a larger building in which they occupied one or two rooms.

Larger residences would have a family section (harem --which, as I'm sure you know, was the family quarters, not specifically the women's section) as well as an area where visitors (unmarried men not related to the household) could be received without intrusion. The sitting room in either quarter was called a qa'a (that's a glottal stop - cah-ah); if you go into a home they'll tell you that "this was the men's qa'a, and that was the women's," but again it's the same difference -- one is where members of the family could gather together, the other was specifically where men could gather with male visitors who could not be admitted to the family quarters on grounds of social acceptability.

In either case, only the largest homes had kitchens (because of the heat) - most of the time food would be purchased out from a vendor. Poor people would eat around it; wealthy folks would send out a servant to buy food and bring it back. Food would be eaten in the sitting area; sleeping would also take place there on cushions that were rolled up during the day. A wealthy family might have another room (or separate qa'as inside and out for winter and summer); poorer families usually slept inside.

Balconies existed--in Christian or Jewish homes the balcony could be exterior (ie., you could see the person sitting up there). In Muslim homes the balcony was interior, covered by a screen like a mashrabiyya--which let breezes pass through, and allowed the occupants to look out, but protected their privacy -- and in mixed neighborhoods (which most were), frequently Christians and Jews would adopt the style of their Muslim neighbors (the environment also played a role here -- the mashrabiyya allowed ventilation but kept the sun out during the heat of the day).

See if you can find Caroline Williams's Islamic Monuments in Cairo: The Practical Guide--she has detailed descriptions of numerous residences in the old city and their parts and functions.