ᐅ Attic Issue: High Humidity – Mechanical Ventilation with Heat Recovery?
Created on: 28 Feb 2018 13:28
S
slygon
Hi
I need your help.
We built a solid structure with Ytong in 2017.
We don’t have a basement but we do have a large attic of 70m² (750 sq ft).
Inside the attic, the walls are plastered.
The entire attic roof space is insulated with a vapor barrier and covered with drywall sheets, but not finished yet (ran out of money).
The ceiling between the second and third floor is also insulated.
Upstairs, there are two triple-glazed windows installed, lying parallel.
Now we have the problem that the humidity inside the attic is above 80% daily. The temperature is always between 5-10°C (41-50°F).
Condensation forms every day on the inside of the window frames and also in the middle of the windows between the frame and the glass.
There is no heating up there, of course, since no one lives there. It serves as a substitute basement.
Can you help me figure out how to control the high humidity problem?
I would prefer not to climb up and down the attic stairs every day to ventilate and then close everything again.
I also left both windows tilted open with half the blinds down for two days. The humidity was high, but the temperature dropped below freezing.
I wasn’t sure if that’s a good long-term solution.
A controlled mechanical ventilation system costs €2000-3000 (about $2200-3300). I already received a quote.
However, no one can explain why this is happening in the attic.
On one side, a stubborn mold stain has already formed on the plaster.
Currently, I run a dehumidifier all day every two days.
But that can’t be a permanent solution.
We really had many problems during the construction phase. And now this too :-(
Can you give us tips or help on how to solve this problem?
Thank you
I need your help.
We built a solid structure with Ytong in 2017.
We don’t have a basement but we do have a large attic of 70m² (750 sq ft).
Inside the attic, the walls are plastered.
The entire attic roof space is insulated with a vapor barrier and covered with drywall sheets, but not finished yet (ran out of money).
The ceiling between the second and third floor is also insulated.
Upstairs, there are two triple-glazed windows installed, lying parallel.
Now we have the problem that the humidity inside the attic is above 80% daily. The temperature is always between 5-10°C (41-50°F).
Condensation forms every day on the inside of the window frames and also in the middle of the windows between the frame and the glass.
There is no heating up there, of course, since no one lives there. It serves as a substitute basement.
Can you help me figure out how to control the high humidity problem?
I would prefer not to climb up and down the attic stairs every day to ventilate and then close everything again.
I also left both windows tilted open with half the blinds down for two days. The humidity was high, but the temperature dropped below freezing.
I wasn’t sure if that’s a good long-term solution.
A controlled mechanical ventilation system costs €2000-3000 (about $2200-3300). I already received a quote.
However, no one can explain why this is happening in the attic.
On one side, a stubborn mold stain has already formed on the plaster.
Currently, I run a dehumidifier all day every two days.
But that can’t be a permanent solution.
We really had many problems during the construction phase. And now this too :-(
Can you give us tips or help on how to solve this problem?
Thank you
You can store almost anything in a cold roof space; this was common practice in the past. Chairs won’t get damaged, nor will dishes, vases, ladders, tools, solvents, and much more. Only items made of fabric would become damp and possibly moldy, and water-based paints could freeze. Cold temperatures are not a problem, but proper ventilation is essential. Churches remained unheated for centuries, yet organs, paintings, and sculptures did not suffer damage. Heat during summer under such roofs can be much more problematic.
netuser schrieb:
About 10L (2.6 gallons) have been extracted in the meantimeSo far, I have extracted around 40L (10.6 gallons) of water from the attic. The dehumidifier only runs during the day. After 8 p.m., it is turned off at the power outlet. In the mornings, the relative humidity is now below 70%. I have the impression that a large amount of water from the screed drying process was still trapped in the wood.
During the plastering, the access hatch was not covered at all, and during the screed phase, a drywall panel was placed on top. From autumn until the staircase installation shortly before moving in, the opening was basically always left open. You can now clearly see how the rough sawn boards are moving and shrinking. I had never noticed any significant gaps before. The remaining plaster was also completely uniform, which is now changing.
Every year, 80% humidity in the attic. The trickle vents in the window frames didn’t help.
I’ve now ordered a dehumidifier again. The good thing is that I already have ventilation up there and therefore also a condensate drain. The dehumidifier will simply be connected to it via a drain hose.
I’m considering installing a Bayernlüfter in the next few years.
I’ve now ordered a dehumidifier again. The good thing is that I already have ventilation up there and therefore also a condensate drain. The dehumidifier will simply be connected to it via a drain hose.
I’m considering installing a Bayernlüfter in the next few years.
We built our house two years ago (solid construction with concrete ceilings).
Basically, the best and most cost-effective option for storage in the attic is to avoid insulating and lining the roof itself and instead only insulate the concrete ceiling below it, right? That’s exactly what we did.
I’ve actually never used a hygrometer up there, since currently we’re not storing anything except leftover items from the construction (tiles, shutter slats, flooring, etc.) 😀
With the roof ventilation, there’s a constant flow of fresh air, and by insulating the concrete ceiling below, there’s no impact on the rooms underneath, correct?
I’d like to move some things from my basement to the attic (snowboard/ski gear, inline skates, and a few airtight sealed boxes). That shouldn’t cause any problems, should it?
Basically, the best and most cost-effective option for storage in the attic is to avoid insulating and lining the roof itself and instead only insulate the concrete ceiling below it, right? That’s exactly what we did.
I’ve actually never used a hygrometer up there, since currently we’re not storing anything except leftover items from the construction (tiles, shutter slats, flooring, etc.) 😀
With the roof ventilation, there’s a constant flow of fresh air, and by insulating the concrete ceiling below, there’s no impact on the rooms underneath, correct?
I’d like to move some things from my basement to the attic (snowboard/ski gear, inline skates, and a few airtight sealed boxes). That shouldn’t cause any problems, should it?
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