What to do about leaking Aco drainage channel

[Postik]

I have an Aco drainage channel that runs the full width of mine and my neighbour's semi-detached garage. If the channel just caught water from the sloped driveway it might not be so bad, however it also catches rainwater from the garage roof which comes from a down-pipe on my side.

I noticed today after clearing leaves out of the channel that one of the joints has a gap and what appears to be a small cavity in the concrete underneath, and rain water is making its way down the gap instead of running the full length of the channel into a drain.

The channel itself is tarmaced in place so not an easy job to replace or to try and close the gap.

Any advice on what I can do to try and remedy this? Attached are a couple of photos.

Thanks

 

[foxhole]

Seal the gap .

 

[Postik]

Seal the gap .

Any recommended sealant I can get from Screwfix?

Also since there is a cavity underneath the gap I feel like I need to pack this out first. Would expanding foam work?

 

[noseall]

Any recommended sealant I can get from Screwfix?

Also since there is a cavity underneath the gap I feel like I need to pack this out first. Would expanding foam work?

It would fill the void that would otherwise fill with water, yes. You would need to be pretty canny with the foam gun though.