Hi,
We had our cement screed installed over 5 weeks ago.
For almost 2.5 weeks now, we have been actively drying our house. The heating curve is already decreasing again.
Unfortunately, we are not able to get the moisture under control. Ventilating more than twice a day is impossible; during the first week, we only managed to ventilate once a day.
Our relative humidity still remains at around 95%.
I wanted to ask how advisable it is to keep two opposite windows slightly open (tilted) on each floor.
Does this make sense, or is it more of a disadvantage?
We had our cement screed installed over 5 weeks ago.
For almost 2.5 weeks now, we have been actively drying our house. The heating curve is already decreasing again.
Unfortunately, we are not able to get the moisture under control. Ventilating more than twice a day is impossible; during the first week, we only managed to ventilate once a day.
Our relative humidity still remains at around 95%.
I wanted to ask how advisable it is to keep two opposite windows slightly open (tilted) on each floor.
Does this make sense, or is it more of a disadvantage?
S
Sebastian799 Dec 2015 19:02So, are you searching again?
Why do you assume that air exchange rates are higher? What about drafts? What about rain? What about wind gusts? What about cold? What about even air distribution?
By the way, exhaust air filters are also installed as standard...
Oh well, I’m sure you’ll say something clever again. But clear sentences would be better – the last sentence is really difficult to read.
Why do you assume that air exchange rates are higher? What about drafts? What about rain? What about wind gusts? What about cold? What about even air distribution?
By the way, exhaust air filters are also installed as standard...
Oh well, I’m sure you’ll say something clever again. But clear sentences would be better – the last sentence is really difficult to read.
If you have a problem, please send me a private message and keep it out of the forums. Do you really need to be aggressive and come close to insulting? Does that belong in this nice forum? You can keep any spelling or grammar mistakes I occasionally make on my phone if you’re the first to notice them.
Instead, find out how high the air exchange rate of a controlled residential ventilation system is and compare it with typical values for windows! You will be surprised how high the air exchange rate is for tilted windows! This clearly shows that the airflow of a controlled residential ventilation system is not sufficient for drying by a long shot (you can even calculate this if you don’t believe it). It’s not about the exhaust air filters inside the ventilation unit, but about those in the valves to prevent the ducts from getting dirty; and these are by no means installed as standard. In addition, at nearly 100% humidity, there is a significant risk of condensate accumulating somewhere in a bend of the ducts.
Therefore, in my opinion, controlled residential ventilation is not suitable.
We have also experienced situations where the window cannot be opened, for example due to rain. That is why I agree with the suggestion of using a construction dryer.
Instead, find out how high the air exchange rate of a controlled residential ventilation system is and compare it with typical values for windows! You will be surprised how high the air exchange rate is for tilted windows! This clearly shows that the airflow of a controlled residential ventilation system is not sufficient for drying by a long shot (you can even calculate this if you don’t believe it). It’s not about the exhaust air filters inside the ventilation unit, but about those in the valves to prevent the ducts from getting dirty; and these are by no means installed as standard. In addition, at nearly 100% humidity, there is a significant risk of condensate accumulating somewhere in a bend of the ducts.
Therefore, in my opinion, controlled residential ventilation is not suitable.
We have also experienced situations where the window cannot be opened, for example due to rain. That is why I agree with the suggestion of using a construction dryer.
S
Sebastian799 Dec 2015 19:52Properly designed mechanical ventilation systems with heat recovery also have filters at the exhaust vents – I know what I’m talking about.
Interestingly, two of my colleagues used the system on a low setting for screed drying – no issues at all, humidity levels around 60 percent, but as a theorist, you’ll probably think otherwise...
Sharp bends in the ductwork are also not present in a properly executed installation. But feel free to explain why condensate forming in the exhaust duct would be harmful. Apart from the continuous ventilation, which dries the space, where exactly is the problem?
Close to insulting? Quite imaginative – honestly. I couldn't make sense of your sentence. If I wanted to mock you, it would look different...
Back to the topic – we’re talking about a building that already has a working heating system. In that case, tilted window ventilation has no place...
When mechanical ventilation with heat recovery is available, it makes more sense to use it with appropriate measures as a drying system during construction – it’s cheaper and works throughout the entire house simultaneously.
Interestingly, two of my colleagues used the system on a low setting for screed drying – no issues at all, humidity levels around 60 percent, but as a theorist, you’ll probably think otherwise...
Sharp bends in the ductwork are also not present in a properly executed installation. But feel free to explain why condensate forming in the exhaust duct would be harmful. Apart from the continuous ventilation, which dries the space, where exactly is the problem?
Close to insulting? Quite imaginative – honestly. I couldn't make sense of your sentence. If I wanted to mock you, it would look different...
Back to the topic – we’re talking about a building that already has a working heating system. In that case, tilted window ventilation has no place...
When mechanical ventilation with heat recovery is available, it makes more sense to use it with appropriate measures as a drying system during construction – it’s cheaper and works throughout the entire house simultaneously.
Sebastian79 schrieb:
Properly designed mechanical ventilation systems with heat recovery also have filters on the exhaust vents – I know what I’m talking about. I know this as well (probably as well as you do). It’s interesting how non-experts can have such different experiences! I know many people who have retrofitted these systems themselves. There are still many manufacturers (including some well-known ones) who don’t offer this feature, but most vents can be fitted with filter bags on your own. Even large and expensive prefab house companies in my region did not include exhaust filters on their vents.
Otherwise, I would just say: What works in individual cases should not be generalized or given as general advice without differentiation and clear communication.
Imagine the homeowner in question has a mechanical ventilation system with moisture recovery (and has little knowledge about it or is not interested!). And that’s how they are drying out their building...
Besides, the speed and amount of drying achieved by using desiccant dehumidifiers is not comparable to a mechanical ventilation system running at a low setting as you suggested.
S
Sebastian799 Dec 2015 20:30And you really think that the moisture recovery is trying to raise the humidity back up to tropical levels?
Well, anyway... the original poster has now received quite a few tips.
Well, anyway... the original poster has now received quite a few tips.
Sebastian79 schrieb:
And you really think that the moisture recovery will raise the humidity back up to tropical levels?
The recovery system doesn’t have intentions, but if it only delivers 80% efficiency, the drying process... well... takes a bit longer :x
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