Last week we had the stone coping removed around our pool and had it replaced with aluminim coping (along with a new liner). We anticipated that the coping would cover the area from the decking to the pool edge (as the previous coping had). However, the coping was not wide enough and rather than discuss the issue with us, the pool company went ahead and installed the coping, leaving us with this 2-3 inch gap around the entire pool, as well as exposed wood and some mortar around the corners.

Any suggestions on how to fill/deal with this gap would be greatly appreciated. Does the coping/wood/concrete pool wall joints need to be sealed to prevent water from seeping behind the wall/liner?

Thank you in advance for any advice!