New Cellar - Heat Issue - HELP !!!

[telacey]

I am looking for guidance. I have a cellar in Florida in a stand alone garage. I have built a 10x12x9 room and it is insulated with the R value of the walls and ceiling are around 39-40. However, I am getting some heat transfer via the lighting fixture. We have a larger metal based lighting fixture that is collecting condensation. I have used foam insulation spray around the fixture in the attic but this does not seem to correct the seepage. I am hoping that someone can assist with advise or ideas to help correct the issue. Please ask questions to clarify anything.

 

[richmke]

What's the room temp and garage/outside temp when the condensation occurs?

Does it occur on high humidity days (or is FL always humid?), or any time?

 

[sour_grapes]

I am a little confused. In what room is the light fixture? You mention a basement in the garage, and I presumed that that is where the fixture is. However, you also mentioned spraying foam around the fixture "in the attic," which I would have assumed means a space ABOVE the garage.

 

[ibglowin]

LOL good one!

Does it occur on high humidity days (or is FL always humid?), or any time?

 

[stickman]

We need more information on how the cellar was built. The key for any cellar, but more important for yours in the Florida heat and humidity, is vapor barrier. You indicated that the walls and ceiling are insulated to R39, what kind of insulation was used, if fiberglass, was any vapor barrier used on the walls and ceiling? What about the floor, is it bare concrete? Concrete will also pass heat and moisture if not properly insulated and sealed. If the cellar is not totally sealed, humidity will find its way in and condense on the cold surfaces.

 

[vacuumpumpman]

I agree with alot of questions that already have been asked

Pictures really help alot -

Actual temperature and humidity gauge readings - inside as well as outside

Are you using metal conduit to run your electricity into your cellar ?

If so I am sure that the conduit gets cold inside the cellar as the conduit then comes out of the cellar and that is where your condensation occurs -

If that is the case - you would have to install a electrical box on the outside and run an extension cord inside to your lighting fixture and or outlets - Just make sure that you use the appropriate size wire.

 

[telacey]

New Cellar - Heat Issue - Part 2

Thank you everyone for all the questions. I obviously see I have left out some information....so here you go...

The garage is climate controlled at 79 degrees via a separate AC system. The cellar is at 55 degrees. The attic has spray foam insulation on the roof itself, however, there is no roof vent. I was planning on adding a roof vent to vent the static hot air, I am sure this will help but I am not sure this will cure the entire issue.

The cellar was built in the fall last year so I did not notice the condensation until recently, probably because the external ambient heat was lower. The light fixture is in the center of the room attached at the ceiling receptacle. It appears that the hot air from the attic is seeping through the receptacle and causing the cold light fixture to condensate. I have gone up into the attic and used spray foam to cover the receptacle but this did not fix the issue. There is not much hot air coming in because it does not seem to affect the cooling unit. The cooling unit registers liquid temperature not ambient temperature. I don't believe the humidity has much affect here because the main garage is climate controlled and room is quite sealed except for this one leak...although my thought process could be off. The cooling unit in the cellar is also metal and there is zero condensation on it so I believe the condensation is because of the roof leak....

There is no basement in the separate garage. We converted a 10x12 room in the garage into a wine cellar. The total square foot in the garage is 1300 on a single floor plan.

All the fixtures are plastic to eliminate the heat transfer. The walls and roof use a fiberglass R34 insulation, the walls and roof were finished with a R6 commercial foam board, and triple coated with liquid vulcanized rubber to create the moisture barrier. My weak point is the door, I should of ordered a exterior door for northern climates, but I have zero moisture on the door or door knob on the exterior of the cellar....but I am sure there is some heat transfer here.

I am wondering if I should increase the R value in the attic. But I believe the fixture in the ceiling is my immediate concern....the second, to vent the heat out of the attic, third, what is the ideal R value for the attic.

Any and all thoughts welcome

 

[gaboy]

Vent the attic would be my 1st thought.

 

[sour_grapes]

I have a cellar in Florida in a stand alone garage.

There is no basement in the separate garage.

Just for complete clarity: Was the statement in your first post an error, then?

 

[telacey]

Maybe a failure to communicate....

I have a wine cellar in Florida in my stand alone garage. Sorry for any confusion.

 

[richmke]

I am guessing that you have warm humid air that is infiltrating through the ceiling fixture. That hot moist air then hits the cold surface of the fixture in the room, and the humidity is condensing on the fixture.

You may need a vapor barrier like this:
http://www.amazon.com/dp/B00EAR9KNC/?tag=skimlinks_replacement-20

 

[stickman]

If I understand correctly, you only put a vapor barrier inside the cellar (on the cold side of the wall). If so, I would add a vapor barrier on the hot side, this would be a vapor barrier just above your fiberglass insulation in the attic. You want to prevent the warm air in the attic from passing through the fiberglass of the cellar ceiling and condensing on the back of the R6 foam board or electrical boxes etc.
If you don't have an exterior door, then be sure to use weather strip all the way around, most interior doors leak like a sieve.
The floor is another source of moisture if not sealed.

 

[sour_grapes]

Ah, I see. I apologize -- the only one who mentioned "basement" was me. That is because, to me, "cellar" and "basement" are synonyms. However, I see you are using the term to refer to your wine storage room. Mea culpa.

 

[vacuumpumpman]

I agree with more insulation on the topside and an attic fan

also why so cold of a temperature at 55 degrees ?

just wondering

 

[ibglowin]

55F is considered the "perfect" cellaring temp.

 

[vacuumpumpman]

55F is considered the "perfect" cellaring temp.

Thanks Mike !

I for some reason thought it was a bit warmer than that

 

[ibglowin]

Blame the French and their caves! LOL

 

[stickman]

I think 55F is a good bottle storage temp, but I go with 59F for bulk aging.

 

[tbuck]

If I understand correctly, you only put a vapor barrier inside the cellar (on the cold side of the wall). If so, I would add a vapor barrier on the hot side, this would be a vapor barrier just above your fiberglass insulation in the attic. You want to prevent the warm air in the attic from passing through the fiberglass of the cellar ceiling and condensing on the back of the R6 foam board or electrical boxes etc.
If you don't have an exterior door, then be sure to use weather strip all the way around, most interior doors leak like a sieve.
The floor is another source of moisture if not sealed.

This! I build wine rooms in Houston Texas and I would think we have the same humidity issues as Florida. The vapor barrier (we use 6mil plastic sheeting) goes on the outside of the room - on the hot side. Then you move towards the cold side with R-30 insulation. Condensation will form at the first point where hot meets cold, so by putting the vapor barrier on the outside, any condensation that might try and form will dry up with the exterior heat.

 

[JohnT]

This! I build wine rooms in Houston Texas and I would think we have the same humidity issues as Florida. The vapor barrier (we use 6mil plastic sheeting) goes on the outside of the room - on the hot side. Then you move towards the cold side with R-30 insulation. Condensation will form at the first point where hot meets cold, so by putting the vapor barrier on the outside, any condensation that might try and form will dry up with the exterior heat.

Hey TBuck..

Do you do this professionally? Any chance you could post some of your work on a new thread>