How to reset set height of stormwater grate?

[amySA]

I am seeking advice as to how to heighten this stormwater point while constructing a path and then set final height once complete. 

I suspect final height will likely be around 8.5cm higher then it is now.

Unsure if what parts to use. 

Outlet is 90mm 

 

[MitchellMc]

Hi @amySA,

You'll likely need a slip coupling. The existing pipe needs to be cut back to allow room for the fitting (100mm long) and the new pipe. Then, a short piece of 90mm pipe will be connected to the slip coupling and the outlet onto it. 

This is considered drainage and plumbing work and requires a licensed plumber for installation.

Please let me know if you have any questions.

Mitchell