Basement

A basement is the part of a building that sits below ground floor level. Depending on the slope of the site it may be fully buried, or one side may emerge above ground and take windows and an entrance. In homes it holds storage, the boiler room, a shelter or parking; in commercial buildings archives, plant rooms and sometimes usable floor space. The Turkish term is bodrum kat.

The big issue below ground: water

Walls and slabs in contact with soil face constant moisture and, at times, water under pressure. That is why retaining walls get a continuous waterproofing layer on the outside, a protection board over it and a drainage system around the perimeter. Waterproofing is among the hardest things to fix once a building is finished, so it has to be right during construction. Groundwater level and soil behaviour come from the geotechnical survey, and the design follows from it.

Making a basement liveable

• On sloping sites the exposed side can turn a basement into a daylit living floor.
• Lightwells, or areaways, dug alongside the walls bring light and air to buried rooms.
• Mechanical ventilation and humidity control keep mould and musty smells away.

How a basement counts in Turkish zoning calculations depends on its use and on the plan notes, so the zoning certificate deserves a careful read early on. In visualisation basements are usually explained through a sectional perspective, which shows the ground, the basement and the floors above in one image.