Thread: Cool room insulation

House has a cool room in the basement to store items at refrigerated temperatures utilizing a condensing unit and evaporator coil (air handler) inside the room. This setup loks like something you would see in a restaurant or grocery store cooler. The walls are all uninsulated concrete (poured) with an insulated exterior door.

Ceiling has fiberglass batts (R-30) with the paper vapor barrier against the bottom of the floor above and drywall installed at the bottom of the TJI's. Drywall is sagging and water damaged due to condensation above it. I know that in a normal installation, the floor insulation above is installed correctly, but I feel that the vapor barrier in this case should have been installed against the "more" conditioned area of the cool room and should have been plastic or maybe even rigid styrofoam or polystyrene sheets (blue board) attached to the bottom of the TJI's instead of paper against the sub floor.

I do know something different has to be done due to the trapped moisture above the drywall ceiling and also feel that the ceiling should be of something different than drywall.


Comments?????

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TJIs would be plural, not possessive. By using an apostrophe (TJI's) the polystyrene ends up belonging to the TJIs.

Oh, wait. You meant comments about the refrigerated room, not your writing...

I would guess that it would be necessary to isolate this "cold room" completely away from the wood framing. I would doubt that any moisture/vapor barrier will be effective because moisture vapor will enter the joist bays from the room above and probably the exterior as well. In the "walk-in" refrigerators that I have seen, the pre-fab panels are rigid foam insulation and an air space is provided around the entire unit. If the wood floor framing gets cold, then any moisture in the vicinity will condense on it. As a result, I think it would be necessary to provide an air space between the floor system for the room above and the top of the refrigerator box as well as any adjacent wood framed walls. Wine cellars do not get to refrigerator temperatures and generally do not have the same problems, but in really humid areas, there is an increased chance, particularly if the dew point is higher than the cellar area.

There are companies that design and build walk-in refrigerators. Your client needs a specialist.

The vapor retarder (paper) does not go to the "conditioned" side as much as it goes to the "heated" side. Under normal circumstances, that is the "conditioned" side, which is why it is frequently stated to go to the "conditioned" side.

That said, though, I would drop a ceiling below the bottom of the TJI and make a refrigerated box below it, allowing for a method to drain off the condensation which collects on the top side of the refrigerated box. I don't know about up there, but those same metal skinned (both sides) insulated panels are available down here at some specialized salvage yards (every time I drive across SR 40 from Ormond Beach to Ocala there is a place along the way).

Use those for the sides, top, and bottom of that refrigerated box, and make sure there is NO WAY for that door to be locked - AND - that there is an unlatching device on the inside of it. A regular insulated door with a regular door knob IS NOT going to cut it.

Of course, if that was done (making it into a proper refrigerated box), you would also need to install the proper refrigeration unit as the air handler probably is now incorrectly sized and would likely be freezing up all the time.

Just some thoughts.

My first (and last) thought was (is): suggest to the buyer that they remove it. If the buyer really wants it, they can leave it, but by suggesting that they remove it, you are suggesting that they remove all associated potential problems too.

Originally Posted by Gunnar Alquist

TJIs would be plural, not possessive. By using an apostrophe (TJI's) the polystyrene ends up belonging to the TJIs.

Oh, wait. You meant comments about the refrigerated room, not your writing...

.
Above Statement attributed to 'The Gun" *aka " The Apostrophe Troll. "
.

The traditional method and terminology is to put the vapor barrier on the

"warm in winter" side of the wall, BUT, traditional thinking is designed for a

heating climate and becomes wrong in some instances.

You need to look at the physics involved. Water vapor generally moves

from warmer to cooler and from wetter to dryer unless there is some other

force driving it in the other direction.

Thus in the situation you describe, water vapor will move from the house

to the cooler room so the vapor barrier belongs on the outside of the box

so that the insulation does not become water logged.

Drop the temperature a few more degrees and ice will form inside the wall

if the vapor barrier is on the inside of the box.

Traditional kraft paper vapor "barrier" is a vapor retarder not a true barrier

and is thus not likely to be successfully employed in this case unless there

is NO vapor barrier on the cool side of the wall.

Even a coat of paint will retard water vapor from exiting the wall.

Drywall is not a good choice for this wall interior, particularly if they are

running a high humidity in the cooler.

Originally Posted by Billy Stephens

.Above Statement attributed to 'The Gun" *aka " The Apostrophe Troll. " .

Ooh... I like it.

I spent years in the restaurant business. Walk-in coolers (cool room) always have air space above them. I agree that the room is attracting the moisture from the house not from the cool room. Drywall even green board would be the last thing I would use. Even water proof gorilla board would not due.
I would remove the existing ceiling and any insulation in the floor above. You may need to clean and bleach the wood above.
I would construct new ceiling panels using aluminum studs. Insulate the space between the studs with rigid foam and enclose it with FRP on both sides. Then install the panels using either a weather stripping gasket like seal at the walls and between panels. Then a good caulk. For what its worth I would cover the walls with a FRP also. Concrete can absorb some moisture and is not as easy to clean.

Just a question? Would a room like this even be part of the HI? How often would you see one of these and how confident could you be in reporting on it. Some may know,however I for one would not.

Bill,

You would not be inspecting the room so much as its negative impacts on the structure housing that room, such as the ceiling drooping between TJI, moisture issues above the ceiling, etc.