The Stone Town is the product of at least three centuries of continuous settlement, but it was only from 1830 that Zanzibar took on a wholly urban character and that stone buildings were built in significant numbers. Until that time, the majority of houses were made of mud and wattle, and roofed with palm leaf thatch. Very few large-scale structures could be distinguished, besides the Fort and a few small mosques.
At the beginning of the nineteenth century, the town occupied only the north-eastern portion of the peninsula, extending from Shangani Point toward the creek's narrowest crossing at Darajani. After the Omani Sultan's permanent move to the island in 1832, the Stone Town quickly expanded during the middle of the century, filling in the areas of upper Sokomuhogo, Forodhani, Kajificheni, and Kiponda. The Omanis erected palaces and residences along and behind the sea front, and tradesmen from the Indian sub-continent built up the bazaar streets with shop-front houses, and sea-faring merchants built houses, sheds, and warehouses near the waterfront. After 1850, stone buildings spread further and began to extend north into Malindi, south into the lower portion of Sokomuhogo, and east to Mkunazini, areas which up to this time had been mostly occupied by mud buildings. As contact with western trading markets increased, particularly once the Suez Canal opened in 1869, and later with the establishment of the British administration in 1890, specialised structures - larger civic buildings in particular - began to appear. The building up of the Stone Town was more or less completed and the present limits defined by the first quarter of the twentieth century: the new port area to the north had been reclaimed, the area south of Shangani built up, the European garden suburb of Vuga laid out, and the programme to fill the creek bordering the peninsula to the east gradually put into effect.
Thus, within the relatively short span of one hundred and fifty years, the confluence of several distinct cultures and the island's intense cosmopolitan development produced the rich and diverse architectural heritage we see today. In some cases, the diversity of the original imports is still evident in different sections of town; in others, the borrowing and adaptation of forms from other contexts produced a cross-fertilisation of different building traditions. In yet other cases, buildings were gradually transformed over time as newcomers adapted existing structures to their tastes and preferences, thus determining a further hybridisation of forms. This variety produced the diverse spaces and surprising contrasts of the Zanzibar townscape, where pedestrians move from the imposing row of sea front structures to the crowded and lively atmosphere of the Indian bazaars, and the quiet, intimate spaces of the narrower residential streets. Thus, although the different forms and building types and their origins - African, Arab, Indian, or European - can be recognised, it is the synthesis of these cultures and influences that creates Zanzibar's unique urban and architectural environment.
Battle, Stephen and Tony Steel. “Stone Houses”. In Conservation and Design Guidelines for Zanzibar Stone Town. Geneva: Aga Khan Trust for Culture, 2001.
These Guidelines have been drawn up to protect the traditional character of the Stone Town. The Stone Town is very special. There is nowhere else in the world like Zanzibar Stone Town. Visitors come from from all over the world to see it. There is nothing like the Stone Town in the rest of Tanzania. It is one of the things that makes Zanzibar different from the Mainland, and special. It is an important part of the island's unique cultural identity. Zanzibar should be proud of its Stone Town.
The Stone Town is the embodiment of Zanzibar's long and great history. It is proof that the island was once the greatest power in Africa, and a great Islamic state. But the Stone Town is delicate. As times change, people wish to change their buildings, or need to carry out repairs. But these changes, unless properly guided, can destroy the Stone Town's special character. Like a shell on the beach, slowly eroded by the waves, each change takes something away, and soon the Stone Town will lose its beauty and fineness, and become like a pebble. If the Stone Town is destroyed, visitors will no longer come to Zanzibar, and the economy will suffer. The best way to preserve the special character of the Stone Town is to repair and maintain buildings using the correct methods, but otherwise to leave them as they are. If changes cannot be avoided, then the changes must be influenced by these Guidelines.
The law requires anyone wanting to do building work in the Stone Town to first ask permission from the STCDA. The STCDA's job is to guide people wishing to do building work so that the changes they make and the building methods they use do not destroy the special character of the Stone Town. The STCDA will judge the building application according to these Guidelines. If the building application follows the Good Practice Guidelines, approval by the STCDA will be quicker and easier.
The foundation is a part of the building that is never seen. It is the job of the foundation to support the weight of the house, so foundations are the first thing to be built and are buried underground. In Zanzibar, foundations are the same as walls except they are a little wider and perhaps made of bigger stones. It is their job to make sure that the building does not sink into the ground or that heavier parts of the house do not sink faster or further than lighter parts.