Cold room condensation


Old 11-29-05, 12:45 PM
Thread Starter
Join Date: Nov 2005
Posts: 1
Post Cold room condensation

I live in northern Ontario, Canada. When the outdoor temperature reaches app. 0 Celsius or colder, the ceiling in my cold room literally "rains" with condensation. The cold room is located under a concrete porch, with access from the basement. It is outside the basement but shares one wall with it. Both the basement and the cold room are poured concrete. The ceiling of the room (where the problem occurs) is corrugated steel, which had served as a form for the poured concrete porch above. The door to cold room is insulated; the walls are not. Help!
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Old 11-29-05, 01:44 PM
Join Date: Jul 2005
Posts: 33
Wow, I don't know what to tell you. I would try a dehumidifier first. It will get some of the extra moisture out, and warm up the room a bit also. Hopefully someone has a better idea though!

I supposed you could insulate the ceiling, but I would be nervous to do that, wouldn't want any moisture to get stuck behind or inside of the insulation or any vapor barrier you might put up.
Old 11-30-05, 05:39 AM
Join Date: Jul 2005
Location: Ottawa, Canada
Posts: 857
Sounds like the room is not vented.
Old 11-30-05, 05:46 PM
Join Date: Aug 2000
Location: USA
Posts: 15,834
Cold room (fruit cellar) condensation

Condensation occurs when warm, moist air makes contact with a cold surface. Cold room should be sealed so that no warm air leaks into it. Insulation of wall joining basement may be helpful. Vapor retarder should cover insulation. Ventilation in cold room would also reduce condensation. An HVAC contractor can install a ventilator unit to bring in fresh air and exhaust damp air. Some units will heat air as it is brought in. There are also automatic condensation evaporation systems that are available. These are often used in wine cellars.
Old 02-02-06, 10:01 AM
Join Date: Jan 2006
Posts: 9
I had this same problem. Same exact set-up. I thought by keeping the door open from the basement side and letting the inside heated air circulate it would be ok. WRONG.

We installed one of those glass block windows in the cold room (we call it a fruit cellar) with the smaller screen window incased in the glass block.

In the winter, we seal off the room and crack the small window so cool air is constantly circulating. It has worked just fine.
Old 09-17-06, 07:57 AM
Join Date: Feb 2006
Posts: 7
I have the same problem in my cold cellar, I live in sout hwestern Ontario 45min west of Toronto. We do have a small vent hole at one end of the cold cellar and a sealed steel door entering the cold room. I nthe summer in gets really musty and in the winter we also have condensation freezing on the cieling. Our cold cellar is 23' x 5' and we can pretty much not putting anything in there because it either comes out smelling moldy or anything that made of cardboard or paper becomes most and damp. I am wondering if there is possibly any solution to this problem.
Old 09-17-06, 08:11 AM
Ed Imeduc's Avatar
Join Date: Aug 2002
Location: Mountain Williams Missouri
Posts: 18,389

Id go with a outside vent in the winter also. If you think about it thats like what we call a walk in box. Only we have a coil in there to keep it cool. That also get ice on it and we have to melt that off now and then and the water runs to a drain. It has to work just like your frost free fridge does to get the water out.

Old 09-17-06, 09:49 AM
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Insulate the walls and ceiling! Vent in heating season!
Old 09-18-06, 06:51 AM
Join Date: Oct 2005
Posts: 18
We also had the same issue and wanted to convert the area into a dry storage area.

At first we tar papered, framed, insulated, vapour barriered and drywalled. Within a week we started to notice the condensation. Not just a slight mist on the inside of the vapour barrier either, I'm talking enough to build up puddles and eventually due to its weight drip pretty steady down the inside of the walls.

The step we took to address the problem was to add 2 vents from the outside into the room. We ran these 2 vents down to about 6" from the floor.

Prior to drywalling the room we gave it a good two months to ensure our moisture problems had gone away. Sure enough we've yet to see a drop of moisture.

I had done ALOT of research on the topic prior to doing the work and I'm sure of one thing. Venting the room is what solved the moisture problems.

Oh, I'm in London Ont. to give you an idea of our climate.
Old 09-24-06, 10:56 AM
Join Date: Feb 2006
Posts: 7
My cold cellar is vented with about a 2"-3" hole, it is located at the top of the wall and has a small screen on it to the outside to keep out the critters.

I put a thermometer in the cold cellar just over the last few days and it said the temp was about 17-18 degrees celcius with a humidity level from 85% to over 90%.

In the house I grew up in we had a small cold cellar but it wasn't vented at all we had no problems with condensation.

I am looking for an easy fix, any help would be appreciated.
Old 09-24-06, 04:40 PM
airman.1994's Avatar
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You need to keep RH below 60%. Don't vent in cooling or no load times!
Old 03-02-09, 06:51 PM
squeakyhinge's Avatar
Join Date: Jan 2009
Location: midwest united states
Posts: 9
Room under porch.

There is existing toilet drain in this corner of basement so bath has to go here. Unfortunately, ceiling is porch floor.

1. Must heat room to rid condensation.
2. Glue foam board to ceiling and tape/caulk gaps.
3. Leave room for 6 inch (not fooling around) bath exhaust with humidity sensor.
4. For walls, vb tucked into french drain, foam board, 2x2 steel studs, air between studs then drywall.

Question, how to attach foam board to walls without screwing into wall? Would glue to block but I must have plastic for french drain.
How to fasten base to floor? French drain has 1-2 inch concrete - doesn't seem tough enough.
Any suggestions, thanks in advance?
Old 12-18-09, 04:19 PM
Join Date: Dec 2009
Location: Ontario
Posts: 1
I also have a cold room under the front porch with a concrete ceiling. It also has the sump pump in this room. There were no condensation issues in the warmer weather.
I didn't want the room to freeze, especially since the sump pump is there. So I blocked the vents during the freezing weather. Quite a bit of condensation on the concrete ceiling since the cold weather arrived. After reading the posts I have opened up one of the vents. Will let you know if this fixes things.

I am still worried that the sump pump will freeze. Any ideas?

I live in Southern Ontario.
Old 11-29-10, 06:50 AM
Join Date: Nov 2010
Location: Canada
Posts: 1

You posted that you opened the vent and I was wondering if your problem was solved.
Old 02-04-14, 08:19 AM
Join Date: Feb 2014
Location: United States
Posts: 2
I have the same issue and had to tear the middle of both walk-in closet last night!! It's just insane the amount of water dripping on the drywall (ceiling)...

My issue is that the studs are actually touching the metal sheet right below the porch concrete. So, how can I fix that. I know that the studs are going to continue dripping since they touch the metal...

PLEASE HELP !!! I was planning on selling the house in March !!

I will appreciate any help RUSH !!!!

Elvin from Utah

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