How to Unclog/Clean a Roof Drain

A roof drain is often used on flat roofs to connect the roof to the outlet pipe. However, they will need cleaning from time to time, as they tend to clog. Leaves can form a blockage or small animals can nest on them. This will cause water to back up on the roof and can lead to leakage that runs into the building.

Step 1 - Inspection

If you have a clog in your roof drain, you will need to inspect it first. Clear any leaves or debris from around the drain and unscrew the cover. Shine a flashlight down to see if you can see anything obvious, such as nesting animals or an accumulation of leaves.

If there are animals, it’s unlikely you’ll be able to remove them from the top of the drain. Under these circumstances, it is best to seek professional advice on the safest and most ethical means of removing them.

Step 2 - Snake

A plumber’s snake will be able to clear most of the clogs. Feed it slowly down into the roof drain until the clog is removed. Depending on how deep or thick the clog is, you might need to repeat this process several times. Keep feeding the plumber's snake through until the clog disperses at the outlet pipe.

Step 3 - Hose

Water under pressure will also clear a clog from a roof drain and flush it down 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.

Initially, the water will back up out of the drain, but eventually, the pressure of the water will begin to loosen the clog. You can push down with the hose at the same time to help loosen the clog.

After a short while, the pressure of the water will make the clog break free and it will run down to the outlet pipe. You will be able to tell when this happens because the water will suddenly vanish down the roof drain as well.

Step 4 - Pipe Brush

An alternative for clearing a clog is to use a pipe brush. Run the pipe brush into the roof drain all the way to the clog. Keep pushing until you dislodge the clog and flush down with water from the hose. The advantage of this method is that water doesn’t back up onto the roof, so there's no water to clean up afterward.

Step 5 - Clean the Roof Drain

Cleaning the roof drain regularly will help stop clogs and cut down on maintenance. It’s especially important in the fall when the trees lose their leaves. Around this time, the roof should be cleaned with a brush every month. The same applies in winter, and regular checks should be carried out to make sure the roof drains clear of ice and snow so that it can function properly. At other times of the year, checking every three months should be adequate.

With the roof clear of leaves, you can begin cleaning the roof drains. Using the hose, run water through each one to make sure it’s draining easily and freely. Use the brush to remove any light debris that might be stuck to the side. Finish by flushing out once more with water and repeat for every drain on the roof.