hello I have a single-story house with an attic. The problem is that so much condensation forms that it drips when the weather changes from cold to warm, the roof is a tile roof with stretched plastic underneath, what can I do to avoid the dripping?
Tile roof with plastic tensioned underneath, you don't have any råspont then?
Where is it dripping from, is it the plastic or is it the lumber or something else?
A photo would have helped...
Where is it dripping from, is it the plastic or is it the lumber or something else?
A photo would have helped...
Please explain what you mean by this advice? That based on the information the OP provides, you advise him to reduce the ventilation. Do you mean that the problems will disappear then?Matti_75 said:
Please explain as I said
Hello Torpalainen. There is no råspont, it's dripping directly from the plastic.
Classic cold attic.
Warm, humid air rises from the house. It meets cold wind, and moisture precipitates when the air temperature decreases. Have you changed anything?
Changed the heating system, insulated, changed the ventilation. One solution is to maintain negative pressure in the house, or let the attic become warmer (heat before the crows).
Various mechanical attic ventilators and moisture guards are also available for purchase. But my advice is to first determine the cause and address it accordingly.
Warm, humid air rises from the house. It meets cold wind, and moisture precipitates when the air temperature decreases. Have you changed anything?
Changed the heating system, insulated, changed the ventilation. One solution is to maintain negative pressure in the house, or let the attic become warmer (heat before the crows).
Various mechanical attic ventilators and moisture guards are also available for purchase. But my advice is to first determine the cause and address it accordingly.
I'm starting to get a bit thoughtful here...
If we start with the facts, condensation forms on cold surfaces where warm/humid air comes into contact.
Where the temperature in the air drops so that it reaches the dew point temperature, i.e. it precipitates water.
The original poster indicates that condensation forms on the plastic when the weather shifts from cold to warm.
At that point, it should still be cold in the attic, and warm air from outside flows along the plastic.
What happens if you decrease the ventilation?
Less circulation, less amount of warm air passing by the cold surface, less initial condensation, but longer time for warming up the attic.
What happens if you increase the ventilation?
More circulation, larger amount of warm air passing by the cold surface, faster warming of the attic, more initial condensation?
What happens if you generally increase the temperature in the attic.
Warmer air can hold more vapor, i.e. the dew point distance increases, less risk of condensation.
Then when it's only warm air, not humid air, i.e. if moisture is added from the residence.
I'm uncertain, I believe I've thought correctly in the above statements.
But what advice should be given for such a problem?
If you make any of the changes mentioned above, what happens when we go from warm to cold weather?
The attic is still warm, it gets cold outside.
Reduced ventilation, still warm in the attic, but the surfaces towards the attic cool from outside, risk of condensation?
Increased ventilation, warm in the attic, but the temperature drops quickly due to the flow of cold air. Reduced risk of condensation.
Please correct me if I'm wrong, I've just tried to list a bit of when and why for the thread...
If we start with the facts, condensation forms on cold surfaces where warm/humid air comes into contact.
Where the temperature in the air drops so that it reaches the dew point temperature, i.e. it precipitates water.
The original poster indicates that condensation forms on the plastic when the weather shifts from cold to warm.
At that point, it should still be cold in the attic, and warm air from outside flows along the plastic.
What happens if you decrease the ventilation?
Less circulation, less amount of warm air passing by the cold surface, less initial condensation, but longer time for warming up the attic.
What happens if you increase the ventilation?
More circulation, larger amount of warm air passing by the cold surface, faster warming of the attic, more initial condensation?
What happens if you generally increase the temperature in the attic.
Warmer air can hold more vapor, i.e. the dew point distance increases, less risk of condensation.
Then when it's only warm air, not humid air, i.e. if moisture is added from the residence.
I'm uncertain, I believe I've thought correctly in the above statements.
But what advice should be given for such a problem?
If you make any of the changes mentioned above, what happens when we go from warm to cold weather?
The attic is still warm, it gets cold outside.
Reduced ventilation, still warm in the attic, but the surfaces towards the attic cool from outside, risk of condensation?
Increased ventilation, warm in the attic, but the temperature drops quickly due to the flow of cold air. Reduced risk of condensation.
Please correct me if I'm wrong, I've just tried to list a bit of when and why for the thread...
Member
· Norrbotten
· 3 390 posts
JOW has compiled it well. All cold attics have more or less condensation, depending on the weather, insulation, and vapor barrier in the roof structure. Still, the cold attics have existed and functioned for a long time. What we have done in recent years that has changed the conditions is further increased insulation in the roof structure and the introduction of insulation materials that cannot hold moisture.
Do you have any alternatives?
- Convert to a warm attic (could be an extensive job), i.e., insulate the outer roof instead and perhaps reduce the insulation, probably difficult in your case with only a condensation plastic as the inside of the outer roof.
- Experiment with ventilation in the attic. You might have to test and get the right conditions in the right weather and/or season. See if you can use openable/closable ventilation hatches. Generally, you want to ventilate more when the attic is warmer than the outdoor temperature, and more limited ventilation when the attic is colder than the outdoor temperature.
- Make sure to use materials in the attic that can buffer some moisture and then dry out during the summer (if it gets extremely hot in the attic in the summer, like 50-60 degrees on a sunny day, not a drop of moisture will remain if it can ventilate a little at the same time).
Do you have any alternatives?
- Convert to a warm attic (could be an extensive job), i.e., insulate the outer roof instead and perhaps reduce the insulation, probably difficult in your case with only a condensation plastic as the inside of the outer roof.
- Experiment with ventilation in the attic. You might have to test and get the right conditions in the right weather and/or season. See if you can use openable/closable ventilation hatches. Generally, you want to ventilate more when the attic is warmer than the outdoor temperature, and more limited ventilation when the attic is colder than the outdoor temperature.
- Make sure to use materials in the attic that can buffer some moisture and then dry out during the summer (if it gets extremely hot in the attic in the summer, like 50-60 degrees on a sunny day, not a drop of moisture will remain if it can ventilate a little at the same time).
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