Filling Gap between sill plate and slab

DaveTile

I'm working on building a new shower. I have a knee wall that is on top of a slab. There is about a 1/4" gap between the sill plate and slab that runs for about 6 inches or so. I would like to fill this but am not sure what to use. i am more concerned about it being structural ok then with stopping any air flow etc.

I will be creating my own mortar bed for the shower. Can i simply just "push" some dry pack under here when I put down the morter bed?

Are there any other suggestions? Maybe some cement patch?

Ron6519

Are you speaking about the wood framing member sitting on the foundation wall(sill plate) or the pressure treated framing member you laid on the slab(bottom plate) when you built the knee wall?
In neither case would the 6" gap be "structural".
In both cases you could fill it with the dry pack shower base material.
Ron