dInca architecture includes some of the most finely worked stone structures from any ancient civilization. Inca buildings were almost always practical and pleasing to the eye. They are also remarkably uniform in design with even grand imperial structures taking on a similar look to more humble buildings, the only significant differences being their much larger scale and quality of finish.

Fond of duality in many other areas, a particular feature of Inca architecture is that it typically incorporated the natural landscape yet at the same time managed to dominate it to create an often spectacular blend of geometrical and natural forms.

Materials

Stone was the material of choice and was finely worked to produce a precise arrangement of interlocking blocks in the finest buildings. The stone was of three types: Yucay limestone, green Sacsayhuaman diorite porphyry, and black andesite. Each block of stone could weigh many tons and they were quarried and shaped using nothing more than harder stones and bronze tools. Marks on the stone blocks indicate that they were mostly pounded into shape rather than cut. Blocks were moved using ropes, logs, poles, levers and ramps (tell-tale marks can still be seen on some blocks) and some stones still have nodes protruding from them or indentations which were used to help workers grip the stone. The fine cutting and setting of the blocks on site was so precise that mortar was not necessary. Finally, a finished surface was often provided using grinding stones and sand.

Features

The vast majority of Inca buildings were rectangular and most of these had a single entrance and were composed of only one room as dividing walls are not common in Inca design. There are some rare examples of multiple-doored long rectangular structures and even buildings which were circular or U-shaped but the norm was for straight-walled structures. Most buildings had only a single storey but there are some structures with two, especially those built into hillsides and the more impressive imperial structures at the capital Cuzco where sometimes there are examples of three-storey buildings.

Inca exterior walls commonly slope inwards as they rise (typically around 5 degrees), giving the building a distinctive trapezoid form. The trapeziod form is more common in the north and centre of the empire and one of its optical effects is to make walls seem higher and thicker than they actually are. The trapezoid motif was repeated in doorways, windows and interior wall niches. Doorways and windows often also have double jambs and the former are usually topped with a large single stone lintel.

Architecture in the capital and the imperial buildings dotted across the empire were remarkably similar in their design to other more mundane structures. They were, of course, often much larger in scale and the quality of their stonework was much higher. They could also be more ambitious in design by employing curved walls and they could be decorated more lavishly, for example, with gold sheeting as at the sacred Coricancha precinct at Cuzco whose curved wall section survives in part today. This duality of lower and higher class buildings being the same yet different was very much a trait of the Inca culture in general.

Inca buildings may have been uniform in their basic design principles and may appear to lack individuality but the names of several architects have survived in the historical record - names like Huallpa Rimichi Inca, Inca Maricanchi, Acahuana, Sinchi Roca, and Calla Cunchuy - which suggests there was some individuality permissible in architectural design.

Structures

Rectangular buildings could be grouped in threes (or more) and arranged around an open but walled courtyard or patio, perhaps the most common Inca arrangement of buildings. This mini-complex is known as a kancha and functioned as administrative buildings, workshops, temples, accommodation or a mix of these. Very large buildings are known as a kallanka and these typically have several doors and face a large open space, often (once again) trapezoid in layout. They were probably used for public gatherings and as accommodation for representatives of the Inca administration and were clear public symbols of imperial control. Palaces were similar in design to smaller buildings just on a larger scale, with finer stonework and very often walled to restrict access and the viewing of royal personages.