Products for Set-back storeys

LORO-X QUATTROFLUX Set-back storey drainage

The trend towards set-back storeys with increased demands regarding the drainage

Modern housing indicates the tendency towards living in the city, but with the feeling of living “in the country”. Thus, the house should at least have a balcony or a loggia; better, however, a big roof terrace. Also, the concentration of urban living space due to the “addition of storeys” – as set-back storey onto already existing buildings – is of increasing importance. Especially in large cities.

A roof terrace is a terrace above occupied rooms. This is of vital importance regarding moisture protection and thermal as well as sound insulation. Every set-back storey drainage has to satisfy special requirements – either as standard or as building-related version.

Normally, it is not allowed to transport rainwater from the roof to balconies and terraces on lower floors. Consequently, the water has to be transported past these areas in a closed system. That is why the water from the roof has to be transported across the roof terrace in a controlled and secure way in order not to flood it.

In comparison to open branch canals a closed pipe system provides a higher security.

4 flow routes in 1 system

A set-back storey drainage as parapet drainage shall be built as discreet as possible at the façade of the building. Still, the main and the emergency drainage from the roof and the roof terrace have to be realized.

This means 4 separate flow routes have to be planned.

Flow route 1: From the roof into the ground pipe
Flow route 2: From the roof into the open
Flow route 3: From the roof terrace into the ground pipe
Flow route 4: From the roof terrace into the open

As prefabricated roof drainage system with measured proof of performance, the LORO-X QUATTROFLUX set-back storey drainage offers a high security when it comes to planning and installation with only one visible downpipe instead of four.

In the main-emergency-combination parapet drain of the roof terrace, one pipe serves as flow route for the main drainage and a second pipe for the flow route of the emergency drainage – the same as in the main-emergency-combination parapet drain of the roof.

Silent siphonic flow with overpressure

When draining the roof, a siphonic flow with overpressure forms in the downpipe between roof and roof terrace.

The siphonic flow “pushes” the water – against the frictional resistance of the two horizontally installed DN 50 pipes – without incline and without disturbing sucking sounds across the roof terrace.

Both horizontal pipes have a small diameter of DN 50 so that a small installation height of the roof terrace covering is possible.

The LORO-X push-fit socket connection enables a fast, easy, secure and precise installation of the two horizontal, pressure-resistant pipes in DN 50.

Small heights

In order to avoid a drainage of the roof onto the roof terrace, the water transporting pipes proceed beneath the surface of the roof terrace across the full storey.

The “speed” – which means a high discharge rate at a small water height – is an important aspect of the set-back storey drainage because the height of the roof terrace covering often limits the water height.

Inclusive emergency drainage and backwater protection

The emergency drainage of roof and roof terrace takes place via the LORO-X QUATTROFLUX collector box as spout into the open.

In the case of backwater from the ground pipe, the high performance safety overflow (HSÜ), positioned in the standpipe of the main drainage, guarantees the emergency drainage into the open.


Video: construction step by step

Alternative solutions

Set-back storey penetration without multi-floor drain