Skip to main content


Häufig gefragt. Schnell beantwortet.

In the course of our consulting activities, architects, planners and roofers continuously ask us questions from the field. Many of these questions recur again and again - and are therefore quickly answered. In the following, we have collected and answered the most basic questions for you. This way, when in doubt, you will quickly find an answer even without a consultant.


What is meant by the term “lost formwork” with the Sita insulating body for outlet? Is it possible to reorder individual parts such as seals from Sita? How often do Sita outlets need to be maintained? Do facade surfaces have to be taken into account when calculating flat roof drainage? What installation distance must be maintained to raised elements? What information is required when sending a flat roof drainage calculation request to Sita? How do you seal the Sita screw-on flange outlets correctly? Can you say approximately how many m² of roof surface area is safely drained by which Sita outlet? What does the xx at the end of most Sita article numbers actually stand for?

Emergency drainage

If a piece of land is completely built over, can emergency drainage be directed onto a public road or area? Can the outlet that is intended for emergency drainage also be connected to the ground pipeline, like the outlet for normal drainage? Why does a SitaEasy have less discharge capacity than a SitaTurbo? Is it always necessary to provide emergency drainage? How high must the emergency drainage be installed?

Conventional drainage

Can any outlet be retrofitted with a pipe sleeve heating system? Can Sita outlets be set directly in concrete? Can main drainage be configured with waterspouts (no downpipe) in the same way as emergency drainage? What is the difference between SitaTurbo and SitaTurbo Max? Why is the discharge capacity of SitaStandard outlets approximately the same in all sizes? How does conventional drainage work?

Siphonic drainage

Is siphonic drainage possible for green roofs? Is a siphonic drainage system noisier than a conventional drainage system? Can the SitaPipe PP pipe also be used for siphonic drainage? How does siphonic drainage work? For which buildings does siphonic drainage make sense?


Is there a limit to the length of the horizontal pipes in the SitaKaskade systems? What is the minimum insulation thickness required for our cascade component? Can condensation occur when using the SitaKaskade Inside? Is the cascade component also available in DN 100? Is there also a cascade component that can be installed above the waterproofing?

Balcony and terrace drainage

Does Sita provide odour traps for the outlets? Can accessibility requirements be met with Sita products? Can a balcony be connected to the downpipe from the roof? If a balcony is covered, how is the drainage calculated? How can I drain balconies that are below each other?


How can the box drain be installed straight on a sloping substructure? When must a mesh cover be placed over the outlet? How can fine grit be prevented from getting into the outlet when a SitaDrain Terra is installed? How wide must the mesh cover be in front of doors? Is the drainage better with slabs on a gravel bed or with elevated structures?

Green roof and Retention

Which Sita outlets are suitable for green roofs? Is emergency drainage required for green roofs? What are the retention options? For which roofs are SitaRetention components used? Why is emergency drainage dimensioned to be larger than normal drainage on a green roof?


How can the inner diameter of pipes and outlets be determined correctly? Can a siphonic drainage outlet also be refurbished with SitaSanis? What does backflow protection mean? Does emergency drainage have to be retrofitted during refurbishment? Can angled outlets also be refurbished?

Ventilation and pipe lead-through

Can covers be used with section vents? What is the best way to refurbish a section vent? What is a pressure loss curve? Can the SitaVent Fireguard be used on industrial roofs? How is the vapour barrier connected for vents and pipe lead-throughs that are not DN 100 and DN 150?

Fire protection

Which fire protection outlet is available from Sita? Does Sita also have an F90 fire protection solution for vents? Can SitaFireguard also be used on concrete roofs? Do F90 roof inlets have to be used in underground car parks?


Can the SitaPipe PP pipe also be used outdoors? Can the SitaPipe PP pipe also be used for buildings taller than 5.0 m? What must be taken into account when fixing Sita pipes? Does the discharge capacity of the pipe change when installed with a slope? Is the SitaPipe Edelstahl pipe system also suitable for siphonic drainage? Are the stainless steel components available in different colours?