To install a roof drain, plan the location of the drain, remove roof bricks at the location where the drain is to sit, fit down spouts, and set gutters into the drains. Use a hosepipe to drench the roof and test the water flow angle of the drain so that no pooling occurs.
Siphon off any pooled water on the roof to decide the location of the drain. A roof drain is ideally located at the roof's lowest point, preferably around the roof's outer edge so that water runs off more easily. Remove a small portion of bricks around the location where the drain is to sit, allowing water to drain off without damaging the building structure.
Fit down spouts to collect water from the roof and redirect it away from the building's walls. This prevents the risk of water coming in contact with and soaking into walls. Use mortar and sidings for flat roofs to seal excess space around the down spouts and prevent leakages. Install gutters carefully to collect and divert water away from the home's foundations to prevent water damage. Finally, test out the newly installed roof drains to ensure all roof water collects in the down spouts and goes into the gutter without pooling.