How to connect a downpipe from the roof to the drain?

Question

Hi,

I'm wondering if someone can help me please....

I need to install something to catch the water that comes off our garage roof and have it run to the drain next to our garage.

Currently the guttering has an round (60mm across) outlet and the drain is terracotta with an opening of 100mm across.

I'm wondering if I need to attach something like this and then run some PVC pipe (round or rectangular) down to the drain.  If so, how do I go from 65mm at the top of the pipe down to 100mm at the bottom?  Should I use square or round PVC?

I've had a good look online but cannot seem to figure it out.

Any help would be appreciated.

Thanks.

MitchellMc · Accepted Answer

Welcome to the Bunnings Workshop community @tmoyn. It's sensational to have you join us, and many thanks for your question about connecting downpipe.

Sticking with Icon 65mm x 3m PVC Round Len Downpipe would be best, as that should mate up with that 60mm dropper. Use can use a couple of screws to hold the PVC pipe to the gal dropper. Icon 65mm PVC Round 112deg Bends will be used to send the pipe over to the wall and then straight down to the drain.

As opposed to connecting it to the drain, you might like to stop it 10cm from it, allowing the water to fall into it. Or, insert the PVC pipe directly into the mouth of the terracotta pipe. Patching cement can then be used to fill around the pipe and create a seal. The larger female end of a terracotta pipe is not readily connected to stormwater, whether that's 65 or 100mm. I'm unaware of a fitting allowing you to connect directly to it. There's a good chance that this is a sewerage pipe to which you are not allowed to connect stormwater in many areas.

Bear in mind that this is considered drainage work and requires a professional for installation.

Please let me know if you have any questions.

Mitchell