Hello everyone,
we are currently building a KFW55 house (actually less since we switched from gas to a heat pump) with a ventilation system and heat recovery. We are at the stage where the screed will be installed either next week or the week after. However, we noticed that all the windows have a ventilation slot (about 10cm (4 inches) of sealing is missing on each window). This can’t be right, can it? Why would there be window ventilation with a ventilation system? We thought the house needs to be airtight, which will eventually be checked with the blower door test. Can this be correct? Are these the wrong windows?
Please help us. Thank you.
we are currently building a KFW55 house (actually less since we switched from gas to a heat pump) with a ventilation system and heat recovery. We are at the stage where the screed will be installed either next week or the week after. However, we noticed that all the windows have a ventilation slot (about 10cm (4 inches) of sealing is missing on each window). This can’t be right, can it? Why would there be window ventilation with a ventilation system? We thought the house needs to be airtight, which will eventually be checked with the blower door test. Can this be correct? Are these the wrong windows?
Please help us. Thank you.
S
SaniererNRW1236 Sep 2022 11:06ismon_rlp schrieb:
My windows have this as well on the outermost of the three sealing layers.
I asked the manufacturer back then out of curiosity: Wow – and the window panes were produced by moonlight so you can see through them better...
Veka 2016 didn’t have this and neither does Veka 2022 – at least in my case.
Otherwise, like @RotorMotor said. The cutouts in the original poster’s and @ismon_rlp’s windows are at the top of the frame. They do not serve as drainage points. I am not aware of any recommendation to deliberately damage a seal. Otherwise, you might as well skip having them altogether.
Martial.white schrieb:
According to Febsterbauer, this is not a rebate vent but prevents moisture and window fogging. SaniererNRW123 schrieb:
Could you explain this in simple terms for a layperson? Which part of the window fogs up – inside or outside? How does it work? Pressure equalization openings in the outer seal primarily help water drain more effectively in the wet zone during heavy wind-driven rain. A beneficial side effect is that condensation in the outer rebate (wet zone) either does not form or occurs less frequently, and dries more quickly. This has nothing to do with fogging of the window panes!
I
ismon_rlp6 Sep 2022 11:11My assumption:
If moisture (condensation or driven rain) forms in the first sealing layer where there is a gap in the seal, it might not drain properly through the drainage system due to a lack of pressure equalization.
Interestingly, I found similar gaps in the outer seals of the old windows I replaced with new ones. Those windows had only two seals and were from the 1990s.
If moisture (condensation or driven rain) forms in the first sealing layer where there is a gap in the seal, it might not drain properly through the drainage system due to a lack of pressure equalization.
Interestingly, I found similar gaps in the outer seals of the old windows I replaced with new ones. Those windows had only two seals and were from the 1990s.
SaniererNRW123 schrieb:
Wow – and the window panes must have been made by moonlight so you can see through better...
Veka 2016 didn’t have this, and neither does Veka 2022 – at least not in my case.
Otherwise, like @RotorMotor said. The cutouts on the OP and @ismon_rlp are at the top of the window. At least they don’t serve for drainage. I’m not aware of anyone courageously destroying a seal. Otherwise, you might as well skip it. Veka and other system suppliers have different solutions for pressure equalization. There are seals that are missing, or there are drilled holes and/or slots positioned at or near the horizontal outer frame at the top. Some window manufacturers omit these pressure equalization openings for windows with low requirements for rain penetration resistance. None of this is standardized.
This has nothing to do with trickle vents!
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