How to fill finished concrete floor gaps along perimeter?

A homeowner building a slab-on-grade house is asking for advice before installing trim around the floor's edge. Their vapor barrier (a plastic sheet under the slab that blocks moisture from coming up through the concrete) was supposed to wrap up the foundation walls, but in some spots it slipped down during the concrete pour, leaving gaps between the slab and the wall. There are also gaps around pipes that come up through the floor near the walls, meant for future hydronic heaters (radiant heating systems that run hot water through pipes).

Trim will hide most of these gaps, but not all of them, and the homeowner wants to seal what's left before covering it up. They're considering a concrete patch product for the general perimeter gaps and a flexible sealant made for concrete around the pipe openings, and asked whether that combination would work or if there's a better approach.

This is a homeowner's question posted to a building-science forum, not a finished how-to guide. At the time this was written, no replies or expert answers had been posted yet. If you're dealing with a similar gap between a slab and foundation wall, or around pipe penetrations in a slab, it's a common enough issue that it's worth watching for responses on that same question, since the right fix depends on things like how wide the gaps are and whether the vapor barrier needs to stay continuous for moisture control.