how to stop condensation in coldstore roof space

[ecclesk]

any ideas guys?

has any one had same problem?

condensation forms on the underside of the cladding in the roof space then drips down onto the insulation which makes up the coldstore ceiling. not good as over time the panels become impregnated with wate/ice.

we have used de-humidifiers on one site and they do help but they cost a fortune to run with the current energy costs.

also we have ventilation fans in some roof spaces they do help a little.

are there any other options?

[Brian_UK]

Is the cold store a separate room within the building or is the roof space that you are talking about part of the cold store itself?

[winfred.dela]

Some plants i have seen with roof condensation problems were insulated using Fiberglass with AVB.

[nh3wizard]

Sounds like a break or separation in the roofing which is allowing heat in causing the moisture or also Ive seen where new lighting has been installed at higher wattage closer to the roof decking causing it to sweat and drip...
Just some thoughts

[winfred.dela]

Sounds like a break or separation in the roofing which is allowing heat in causing the moisture or also Ive seen where new lighting has been installed at higher wattage closer to the roof decking causing it to sweat and drip...

The moisture from the roof could be due to high air temp/humidity inside the building and low roof temperature (maybe due to low ambient air temp).
The inside air dew point is reach thus the accumulation of moisture in the roof underside.

By insulating, the roof temperature (lower than the air temp. inside the building) is separated from the higher temperature/humidity air inside the building.

Another problem attributed to this Roof underside moisture accumulation is the rusted roof, trusses and purlins.

Moisture in the metal roof underside can also be seen in boiler rooms during low ambient air temperature.

. . .

[smpsmp45]

We in India face this problem in almost all the cases. That condensation is due to Moisture form outside air which is moist.

We have used Extra Ante room in the cold store entry to minimise this problem. So also by putting the doors of cold stores & Loading station in Perpendicuar direction , we have seen this problem is further reduced.

[Psychro]

any ideas guys?

has any one had same problem?

condensation forms on the underside of the cladding in the roof space then drips down onto the insulation which makes up the coldstore ceiling. not good as over time the panels become impregnated with wate/ice.

we have used de-humidifiers on one site and they do help but they cost a fortune to run with the current energy costs.

also we have ventilation fans in some roof spaces they do help a little.

are there any other options?

This is a common problem in ventilated roof spaces above cold rooms. It relates to the dewpoint of the air within the roof space. The roof space and structural supports are usually a few degrees below ambient temperature so the relative humidity of the air (from ambient) will be higher than ambient. If the ambient air was already at say 90%RH then it only takes a 1~2°C drop in temperature to reach saturation (this usually starts on the cold steel roof supports). Attempting to control the dewpoint using a desiccant type dehumidifier is the answer and whilst you say you've already used dehumidifiers, you didn't say which type . Refrigeration type dehumidifiers are unlikely to achieve the lower dewpoints required to stop the condensation. In order for any dehumidifier to operate effectively, the roof space would require sealing (and no ventilation). Desiccant dehumidifiers that use direct fired natural gas burners for reactivation are available so they are much cheaper to operate than all-electric dehumidifiers ! Mechanical ventilation of the roof space is likely to exacerbate the problem as this can introduce more available moisture (more condensation!) from ambient . Visit dst-sg.com.
Hope this helps. Regards
Psychro

[Josip]

Hi, Psychro

This is a common problem in ventilated roof spaces above cold rooms. It relates to the dewpoint of the air within the roof space. The roof space and structural supports are usually a few degrees below ambient temperature so the relative humidity of the air (from ambient) will be higher than ambient. If the ambient air was already at say 90%RH then it only takes a 1~2°C drop in temperature to reach saturation (this usually starts on the cold steel roof supports). Attempting to control the dewpoint using a desiccant type dehumidifier is the answer and whilst you say you've already used dehumidifiers, you didn't say which type . Refrigeration type dehumidifiers are unlikely to achieve the lower dewpoints required to stop the condensation. In order for any dehumidifier to operate effectively, the roof space would require sealing (and no ventilation). Desiccant dehumidifiers that use direct fired natural gas burners for reactivation are available so they are much cheaper to operate than all-electric dehumidifiers !
Mechanical ventilation of the roof space is likely to exacerbate the problem as this can introduce more available moisture (more condensation!) from ambient . Visit dst-sg.com.
Hope this helps. Regards
Psychro

Good direction marks

Just to make some small help regarding page you suggest, seems very good to spend some time here

www.dst-sg.com

Best regards, Josip

[odza]

You should have left some space between for ventilation if you want to avoid condensation i.e between the main wall and your panels