Here is a new commercial building that did not properly address waters from the roof drains from design and build. 4″ corrugated piping can be seen used as an after-thought to attempt to get the roof water away from the building slab. Distance traveled away (left in pic) from the building in the turf area was elevated in comparison to building slab. Same holds true off the far-pictured corner.
The proposed solution is to install an underground piping network with an outlet in the paved area of the parking lot. The downspouts will outlet to individual inlet basins. This allows for debris to exit the network and provides for a lower maintenance operation. This is not common for a residential application because volumes are commonly less and the basins add an expense that’s not always desirable to pay.
The network piping is to be a large enough diameter to handle the tributary capacities as well as small enough with smooth inner walls to maintain velocities that perform self-cleaning actions. All basin lids are removable to allow cleaning maintenance access.
The solution implemented was an 8″ SDR35 pipe mainline with 6″ basin-to-main PVC piping. As this was a relatively short distance overall, and we wanted to keep the mainline close to the building for terrain reasons, we performed a hand-dug trench. The piping was laid using a level and laser to ensure proper slope. All PVC was glued and the SDR main is a rubber gasket seal. It is important when dealing with greater than residential flows, that the conveyance happens without any future piping separation. As this system could also see a surge due to handling roof runoff, the basins prevent the system from becoming pressurized due to any tailwater conditions. Because there was limited fall available it was important to get the outlet as low as possible. This resulted in the outlet to be within the parking area. A more sturdy basin and grate were required as well as some paving removal and replacement.
Re-installation of the soils and existing sod completed the project. They now have a gravity-flow, low maintenance resolution to what was quite the new construction oversight.
Be sure to check out the complete gallery below and call us with your troubled commercial property. We’d love to put it in the past for you as well.