Damp attic since insulation

[roker]

bstop: that statement puzzles me, how can the attic be colder than the outside air?

 

[bstop]

If there is a rapid rise in outside air temperature due to changing weather conditions, the temperature of the attic structures will be colder than the outside air for a considerable warm up time period. These rapid rises and falls in outside temperature are regular in Ireland and often quite dramatic. Last Christmas the outside temperature changed from -15 to +10 Degrees over a period of hours into Stephens Day.

 

[bmcintyre]

If there is a rapid rise in outside air temperature do to changing weather conditions, the temperature of the attic structures will be colder than the outside air for a considerable warm up time period. These rapid rises and falls in outside temperature are regular in Ireland and often quite dramatic. Last Christmas the outside temperature changed from -15 to +10 Degrees over a period of hours into Stephens Day.

That's a pretty rare occurrence though, all the same.

 

[bstop]

Rapid temperature changes are a common occurrence in Ireland's changeable climate. The change at Christmas 2010 is an extreme example.

 

[bmcintyre]

Rapid temperature changes are a common occurrence in Ireland's changeable climate. The change at Christmas 2010 is an extreme example.

Rapid changes are relatively common but the temperature differential involved is rare.

The most common occurrence of condensation in an attic after installation of insulation, by far, is the ventilation being blocked off by the insulation or that it was an older house with a weak airflow into the attic but one just about strong enough to ventilate before the extra insulation was put in.

 

[roker]

That is exactly what happened to my house, the insulation was blocking the vents, plus the shower extractor was not ducted to the outside, but I recall the severe low temperature was for a couple of weeks and my attic was dripping. I will add that there must be no entry for the warm air from the house to the attic, this carries moisture.

 

[bstop]

Rapid changes are relatively common but the temperature differential involved is rare.

What does this statement mean?

If there is a rapid change in temperature then there is a temperature differential.
Temperature change and temperature differential are the same thing.

A rapid rise of a few Degrees C of outside air is all that is required to cause attic condensation. This is not a rare event in Ireland and better ventilation of the attic will increase the condensation under these conditions.

My point is that no matter how well your attic is ventilated it will become wet inside under certain weather conditions. There is nothing you can do to avoid this and calling in experts to cure this problem is a waste of time and money.

 

[roker]

With warm air on the outside, surely the condensation will be on the outside not the inside. Its the warm air that carries the moisture

 

[bmcintyre]

Rapid changes are relatively common but the temperature differential involved is rare.

What does this statement mean?

If there is a rapid change in temperature then there is a temperature differential.
Temperature change and temperature differential are the same thing.

A rapid rise of a few Degrees C of outside air is all that is required to cause attic condensation. This is not a rare event in Ireland and better ventilation of the attic will increase the condensation under these conditions.

My point is that no matter how well your attic is ventilated it will become wet inside under certain weather conditions. There is nothing you can do to avoid this and calling in experts to cure this problem is a waste of time and money.

That statement meant that temperature changes of 25 degrees are very rare in Ireland.

If you're trying to suggest that the scenario you've outlined is just as big a cause of attic condensation, then we'll just have to agree to disagree.

 

[bstop]

With warm air on the outside, surely the condensation will be on the outside not the inside. Its the warm air that carries the moisture

The warm outside air enters the attic if it is well ventilated and wets the inside as I have previously explained.

 

[bstop]

That statement meant that temperature changes of 25 degrees are very rare in Ireland.

If you're trying to suggest that the scenario you've outlined is just as big a cause of attic condensation, then we'll just have to agree to disagree.

I have stated that the scenario I have outlined is a cause of attic condensation. I have not stated that it is as big a cause as anything else as you are suggesting.

To be clear a differential of 25 Degrees is not necessary to cause condensation to occur. Any temperature differential will result in condensation. Warm moist air in contact with a colder surface = condensation.

 

[roker]

bstop:
I disagree. If you heat up cold air it will go dryer and can absorb more moisture, so it will be dryer inside, it’s measured as Relative Humidity.
When I was living abroad in a hot country, I had my air condition on inside the house and the windows used to condense on the ouside.

 

[bmcintyre]

I have stated that the scenario I have outlined is a cause of attic condensation. I have not stated that it is as big a cause as anything else as you are suggesting.

I wasn't suggesting that you were making a particular point, which is why I said "if you are suggesting".

I'm just saying that increasing the ventilation of the attic will significantly reduce the incidence of condensation in the attic.

Or rather, I am suggesting that increasing the ventilation of the attic will significantly reduce the incidence of condensation in the attic.

Since there's a lot of suggesting going on.