Two-Part Design

A drain is described as two-part when it consists of a base unit for sealing to the vapour barrier and an upgrade element with drain body for sealing to the waterproofing membrane, with the thermal insulation located between the two.

Two-part drains are used as two-part flat roof drains on warm roofs and as two-part balcony drains on insulated balconies.

On two-part drains the base unit has no drainage openings and is connected to the upgrade element in a backflow-proof manner. To counteract any movement of the roof structure, it is recommended that the upgrade element also be connected to the substrate.

Two-part drains should not be confused with drains for two drainage levels!