Reefer/Icebox refit questions

[Reefpoints]

Hello, I am rebuilding my reefer/icebox in-place and have some questions for those with experience or insight. So far I've completely removed the old icebox (fiberglass liner) and all the old insulation. My questions are:

1) Is it okay to directly build up the icebox (with insulation then fiberglass) against the hull?

My concern is that the hull may flex or twist slightly relative to the rest of the galley cabinetry. If I find myself offshore in storm and the hull does flex relative to the cabinets, then the inner icebox (fiberglass surface) itself could crack or maybe break free of the insulation. If that happened, then that would be a potential path for airflow which would prevent the insulation from working. Or am I overthinking this?

The alternative would be to build a free-standing back wall attached directly to the cabinet sides and offset from the hull. The problem there is that the hull is a very complex contour with a structural rib right in the center. The offset wall would end up eating up a very large portion of the volume available.

2) How do you apply a vapor barrier with 2-part foam (like Dow's Froth Pak, Tiger foam, or pour-in foam)? Do I spray/pour first, then apply a vapor barrier and then continue insulating with board foam? Or do I apply vapor barrier then spray?

My concern would be that if I apply vapor barrier then spray foam - if I accidentally step on the vapor barrier or miss-handle it while doing other work - it will pull off the spray foam.

Thanks in advance!

[dsiddens]

Two thoughts: put a boundary layer between the hull and the insulation. Neoprene foam, reflective bubble sheet, even recycled white flexible packing foam sheet. I've used the reflective bubble stuff on our boat and it seems to be effective.
Second thought: provide a chase of a tubing or plastic pipe of sufficient I.D. to pass the fittings of the gas hose. A day will come when that hose needs to be changed.

[wingssail]

Originally Posted by dsiddens

Two thoughts: put a boundary layer between the hull and the insulation. Neoprene foam, reflective bubble sheet, even recycled white flexible packing foam sheet. I've used the reflective bubble stuff on our boat and it seems to be effective.
Second thought: provide a chase of a tubing or plastic pipe of sufficient I.D. to pass the fittings of the gas hose. A day will come when that hose needs to be changed.

Good tips from dsiddens. We, however, placed the insulation directly against the hull (shaping it for the stringer and, in our case, a fresh water line). We have had no trouble with hull flexing. We built the liner of fiberglass after the insulation was completed and sealed. It was finished with two part polyurethane.

We learned:

• Make the floor of the box flat (or put in a shelf)
• Make sure that no air gaps exist in the insulation between the liner and the exterior hull.
• Follow the manufacturer's installation instructions for placement of the evaporator plate, the lines, and the thermostat sensor.
• Use care in the placement of the compressor and the condenser. For air cooled systems, air flow is important.

[1affiah]

You are on the right track. The previous posts are good advice as well, especially the route for the gas line. Good news is that your plywood is new or great shape, I would thoroughly coat it with epoxy before proceeding to build out your box with foam. I used blue (or pink) 1" and 2" foam board and the spray foam to glue the seams.

[1affiah]

I'll bet someone chimes in to say that the froth pak type foam will absorb more moisture over time, (than board insulation) and I think that is probably true. I would use the mylar bubble insulation (Lowes or HD) for vapor barrier all around, and the can foam only for seams and large gaps.