I recently added a new garage with living space above it. To get plumbing to the new upstairs I had to go through a newly constructed 2x6 wall that separates the garage from the house. The lines are wiresbo pex and run in the center of the 2x6 so there is about 2.5" on either side of the line. They run through about 30' of wall and transition up into the ceiling of the garage. The ceiling of the garage is 16" TGIs and will be filled with celulose so there is little chance of freezing up there. The area above the garage is conditioned living space. My major concern is pipe installed in the 2x6 wall cavity. The garage is setup for radiant heat but that may not get done by next winter so I want to set this up to work under those conditions. I am thinking of using standard fiberglass insulation and also installing the foil (bubble wrap) on the cold side of the wall as extra insulation. Another thought was to put the split foam on the pipes in addition to the fiberglass insulation. The garage itself will be well insulated but our temps dip to 0F at times in the winter so it could be possible that the garage itself may see freezing temps. Any input is greatly appreciated.