At minimum you should do this.
How to keep drain on flat roof from clogging.
A roof drain is often used on flat roofs to connect the roof to the outlet pipe.
Feed your hose down the roof drain until it sits against the clog and then turn it on at full power.
Leaves can form a blockage or small animals can nest on them.
The most obvious recommendation is to regularly inspect and clean your roof drains.
The feet of the ladder should be completely flat against.
Keep the roof deck clean.
Flat type roofs with a curb should have secondary over flows so if the primary one clogs up stuff can get off the roof through the secondary over flow.
Check these secondary overflows to make sure that they are clear and free flowing as well.
However they will need cleaning from time to time as they tend to clog.
Your washing machine faucet would be a good choice.
Position a ladder against the side of your house that features the clogged roof drain.
You can push down with the hose at the same time to help loosen the clog.
Buy the right roof drain dome.
Initially the water will back up out of the drain but eventually the pressure of the water will begin to loosen the clog.
Regularly clean the drains.
You can use this method in addition to the brush method to completely unclog roof drain.
Remove impediments to good drainage on the roof including keeping tree branches away from the roof making sure leaves don t clog roof drains removing debris left from contractors who work on the roof and cleaning out areas around roof mounted equipment.
How to prevent flat roof drains from clogging.
The best way is to connect the hose to a faucet which provides hot water and use the hose to run down the debris.
Scoop debris such as leaves and pine needles from the gutters drains and the top of the.