Radmat Blue Roof systems are designed by our in-house team to achieve the required attenuation volume and/or the required discharge rate, with discharge rates significantly below the greenfield run off rate of 5 litres a second equivalent being achievable. No special rainwater outlets are required for the Radmat Blue Roof system, our flow control and overflow devices work with any brand of rainwater outlet. We do however recommend the inclusion of a telltale provision as with any temporary or permanent water holding system.