Pointing joints between Indian sandstone and channel drain

[machtucker]

Morning,

I have laid a patio with an Aco channel drain at one end. The slabs next to the drain have about 5mm gap and are about 5mm higher than the side of the drain. 

I have Sika Fastfix jointing compound to joint the patio. What is the best way to joint the drain gap? Obviously it needs to be filled properly so the water runs into it. Should I just work in the fastfix or use mortar? I have a mortar gun which I guess will make filling it easier. 

Any recommendations would be good. 

Thanks

Ed

Edited July 20, 2023 by machtucker

[Mr Punter]

Mortar will work OK.  I struggle with the gun sometimes as they can block and make me rage.  Other times they are fantastic.  5mm is very narrow so a trowel may work better.

[machtucker]

Cheers, I will give that a go. 

[Andehh]

Mortar coloured cikione works well, esp as plastic acros can flex!