What is the fifth facade?
The fifth facade is the roof of a building, regarded as a fully-fledged fifth exterior alongside the four facades. In Dutch it is called the vijfde gevel. With this term architects indicate that a roof is more than a watertight covering: it is visible from taller buildings and from the air, and it can be used. The term is used mainly for flat roofs.
Origin
In the Netherlands the concept is associated with the architect Robert van ‘t Hoff and his Villa Henny in Huis ter Heide (built from 1915), an early example of a villa with a concrete frame and a flat roof. The influence of Frank Lloyd Wright is clearly visible in that design. Later, Le Corbusier made the roof terrace one of his five points of a new architecture.
Possible functions of the fifth facade
- Roof terrace or roof garden for outdoor space in the city.
- Green roof with sedum, herbs or intensive planting: slows down the run-off of rainwater, cools in summer and protects the roof covering against UV.
- Water storage (retention) to hold back cloudbursts.
- Solar panels and building services such as heat pumps and ventilation units.
- Daylight via rooflight domes, continuous rooflights or light tubes.
Tips if you want to use the roof as a fifth facade
- Have the load-bearing capacity checked first. A saturated green roof, a tiled roof terrace or water storage is much heavier than a bare bitumen roof. Have a structural engineer assess the load on the existing roof structure.
- Get the roof covering in order first: only lay a green roof or terrace on a roof covering that will last for years yet and is root-resistant. Repairs underneath are expensive, because everything has to come off.
- Railings and edge protection: a roof that can be walked on needs a fixed balustrade; in the Netherlands a roof terrace often requires an environmental permit (omgevingsvergunning).
- Falls and drainage: make sure water does not stand and that emergency overflows stay clear.
- Design the building services in: position plant so that it is as inconspicuous as possible from the street and from taller neighbours, or enclose it in a housing.
Related terms
- Facade
- Green roof
- Roof covering
- Continuous rooflight
- Rooflight dome
- Rooflight
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