Problems with condensation in garage

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:( I have a detached double garage at my home.It is 9metres x 6metres and is built with cavity wall.However in winter when the temperature rises following a cold spell condensation forms(a lot) on the walls and other items in the garage.Is there any solution to this problem?
 
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has it not got air bricks, or a small window you can open very slightly?
 
breezer said:
has it not got air bricks, or a small window you can open very slightly?
It has windows and a roller door but when I open them the problem appears to get worse
 
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masona said:
What sort of roof have you got?
The roof is basically the same constrction as the dwelling house with felt and concrete tiles
 
Sounds like you have trap condensation with no proper air flow.Ventilation is vital to replace moist, stale air with fresh clean air so you need plenty ventilation like soffit air-vent , roof ridge air-vent type , roof tile vent and higher wall air-vent brick so you got continuous circulation air change from top to bottom.The more you do the better.Another option is to fit a Condensation Control Fans in the window which is design for shower/bath.
 
masona said:
Sounds like you have trap condensation with no proper air flow.Ventilation is vital to replace moist, stale air with fresh clean air so you need plenty ventilation like soffit air-vent , roof ridge air-vent type , roof tile vent and higher wall air-vent brick so you got continuous circulation air change from top to bottom.The more you do the better.Another option is to fit a Condensation Control Fans in the window which is design for shower/bath.
Thanks,I already have the soffit vents but I will fit the roof ridge vents and roof tile vents
 
i am also thinking that you only have a "one way road" air can either get in or out but not both. as masona said you need to have a flow of air, so if all vents (sofit) are at same level, there is no where for the air to flow.

perhaps if you could put in an air brick or two lower down it would help. Then it can flow from air bick up to ridge vent and out
 
breezer said:
perhaps if you could put in an air brick or two lower down it would help. Then it can flow from air bick up to ridge vent and out
Good point,I've missed that regarding roller door type tend to seal the bottom as with up & over garage door have a gap underneath for air flow.I was wondering if you could drill a few holes along the bottom of your roller door providing it doesn't rust etc......
 
masona said:
as with up & over garage door have a gap underneath for air flow.

or if the truth were known, because they never properly fit :LOL:
 
If I put some heat in the garage would this help,or would the ventilation on its on be sufficient?
 
heating will make it worse since the hot air will condense on cold walls
 
To be honest it does not sound like ventilation is the issue here.

To understand why condensation occurs in any given scenario requires an understanding of the relationship between wet and dry bulb temperatures, relative humidity and dew point. This relationship can be ascertained from something called a Psychometric chart. You can see one on this site by clicking on the appropriate link. See here

A given volume of air can hold a maximum quantity of water vapour at a fixed temperature. However raising the temperature of the air allows it to hold more water vapour, whilst cooling the air causes the vapour to condense.

In a house large volumes of water vapour are produced by cooking, bathing and the occupants breathing. This moisture needs to be expelled from the building by ventilation. Rising warm air takes much of this vapour into the roof space, where the air is cooled and condensation is likely to occur. Hence the importance of good ventilation in the roof space of a house.

However, it is unlikely, unless you are spending a lot of time in there, that much moisture is produced in your garage. In all likelyhood the air in your garage is generally at equlibrium with the outside air, so ventilation would have little or no effect.

I cannot be certain (these problems can be awfully difficult to diagnose), but it seems to me that your problem is likely to be caused by a phenomenon known as "Clear Night Radiation".

It isn't something I am going to find easy to explain unless your Physics is up to scratch...... Heat flows from a hot body to a cooler body by radiation and the greater the difference in temparature the faster the transfer of heat. The coldest thing in the universe is space itself, so on a clear night (no cloud cover) your relatively warm garage gives up heat at a massive rate of knots to the blackness of the sky.

This is the same phenomenon that causes your car windows to ice up (even when there is no ice or snow elsewhere and often when the ambient temparature is actually above freezing.

Clear Night Radiation is actually a very big problem with some types of building, notably aircraft hangers where it can actually rain indoors because the roof areas are so great.

If I am right then your only practical solution is to provide some heat (it wouldn't need to be a lot). The heat will have two physical effects. Firstly it will raise the air temparature, allowing the air to hold more moisture. Secondly it will increase the air pressure in the garage which will tend to ensure that air flows out of it.
 

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