Proper Plumbing for flat roof drainage?

[bobertbeen]

I hope everyone is doing well and I hope it's ok asking for some professional insight into a design issue in my strata building please.
I have searched high and low and wanted to be more informed on what could have been done better to potentially avoid this happening again

For context: I live in a strata complex and we had our roofs completed replaced in the last 18 months. We have asphalt shingle with flat membrane roofs on top of each building. We replaced all the hardware and gutters and downspouts. There are cone drains on the flat membrane attached to gravity fed PVC pipe that runs through the attics to the gutter downspout.

This past winter, it was a perfect storm. Prolonged freezing with a sudden period of rain storms caused the gutters to freeze literally only where the downspout came out the soffits.

Please excuse the question but is it proper to have the PVC pipe floating coming off the downspout cone from a flat roof. With the heavy water run off and the gutter frozen at the soffit, the water backed up to where the cone connected and overflowed into a few attics. I posted a small picture to show the connection.

It was explained to me that the pipe floats with the hanger to allow for building shift. I can see the logic in floating as well as having it sealed.
Can anyone advise if they have seen / come across this and what might be the proper method to prevent leaking?

Thank you in advance!!! Comments are greatly appreciated
Robert

 

[Paul Sweet]

There are ways to let the drain move up & down slightly and still have the pipe sealed. A horizontal offset of a few feet is one way.

 

[e hilton]

When you ask about the pipes “floating” … are you saying the pipe off the bottom of the drain body is just loosely poked into the main drain line? It’s not a sealed connection?

 

[bobertbeen]

Thank you for responding. Sorry if I did not explain it well enough.

In the image below I circled where the pipes join. The copper cone on the roof pipe portion was and is just seated several inches in the PVC pipe that runs, on a grade, to the gutter.
It is a snug fit but I would have thought "maybe" it would have a hose clamp or something.
It was explained that this is loose to allow for sway in the building which sort of makes sense.

I have looked high and low to see if there is some code or standards for membrane/flat roof drainage to gutters but can find nothing on how they actually get fastened. Is this proper or is there another way it should have been done?
I personally think the stars just aligned and we had the perfect mix of going from prolonged cold to torrential rain.
Any thoughts are greatly appreciated.

 

[ICE]

I don’t know Canadian code but apparently it didn’t work.