ᐅ Getting Moisture Out of a New Build – How to Ventilate and Other Related Topics
Created on: 22 Nov 2021 18:10
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XxTankerxX
Hello everyone,
The shell of our house was recently completed. Our regional window supplier had a delay with a larger order, so we received our windows just 3 1/2 weeks after measuring—shortly after the roof structure was finished. In my opinion, this was almost too early, but I wasn’t given much choice since otherwise we wouldn’t have gotten them this year. Naturally, the house still contains a lot of residual moisture. The floors (especially in the basement) are now dry—or at least they look dry. However, many bricks (especially in the basement) are still dark-colored and damp. I’m also measuring a humidity level in the basement air of about 84%.
About the house: The basement is a waterproof concrete basement (WU-basement). The interior walls and all floors above ground level (ground floor and upper floor) were built with Poroton blocks.
Now to my main questions:
- What is the best way to ventilate? Currently, I have all basement windows tilted open. On the ground floor and upper floor, I have some windows (on opposite sides) open to create cross-ventilation. Is that sufficient?
- Following up on that: I still need to insulate the top floor ceiling with EPS035 (the insulation arrived today), and a waterproof membrane needs to be installed in the basement. When is the best time to do this, or how long should I wait before proceeding? I want to avoid trapping moisture underneath and causing mold in the end.
I’m interested in your opinions and how you handled similar situations during your build.
Kind regards,
XxTankerxX
The shell of our house was recently completed. Our regional window supplier had a delay with a larger order, so we received our windows just 3 1/2 weeks after measuring—shortly after the roof structure was finished. In my opinion, this was almost too early, but I wasn’t given much choice since otherwise we wouldn’t have gotten them this year. Naturally, the house still contains a lot of residual moisture. The floors (especially in the basement) are now dry—or at least they look dry. However, many bricks (especially in the basement) are still dark-colored and damp. I’m also measuring a humidity level in the basement air of about 84%.
About the house: The basement is a waterproof concrete basement (WU-basement). The interior walls and all floors above ground level (ground floor and upper floor) were built with Poroton blocks.
Now to my main questions:
- What is the best way to ventilate? Currently, I have all basement windows tilted open. On the ground floor and upper floor, I have some windows (on opposite sides) open to create cross-ventilation. Is that sufficient?
- Following up on that: I still need to insulate the top floor ceiling with EPS035 (the insulation arrived today), and a waterproof membrane needs to be installed in the basement. When is the best time to do this, or how long should I wait before proceeding? I want to avoid trapping moisture underneath and causing mold in the end.
I’m interested in your opinions and how you handled similar situations during your build.
Kind regards,
XxTankerxX
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Oetzberger23 Nov 2021 10:36Despite the common wisdom shared here: If you don’t want to take a multi-month construction break for slow and “natural” drying with open windows until April, then only a technical drying acceleration will help you. Although it has no chance of completely drying the building, at least it prevents moisture from moving backward. Soon, hundreds of liters of water will be introduced again with the screed and plaster, so proper drying becomes even more important. It’s best not to save on heating and dryers.
Some of the things written here are really off... as if a shell construction is built today the same way it was 30-40 years ago. Most of the moisture will still come in through plaster and screed anyway; in 100m² (1,076 ft²) of screed, 6cm (2.4 inches) thick, there is over 1m³ (35 cubic feet) of water.
If it is "soaking wet" somewhere, just set up 1-2 construction heaters, powered by gas or electricity, and let them run for a few days. In winter, you can ventilate the moisture out perfectly.
If it is "soaking wet" somewhere, just set up 1-2 construction heaters, powered by gas or electricity, and let them run for a few days. In winter, you can ventilate the moisture out perfectly.
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XxTankerxX23 Nov 2021 22:28Hello everyone,
Thanks for your opinions.
Just to clarify:
- No screed or plaster has been applied in the house yet, and this won’t happen before April next year.
- My main goal is to remove the rough moisture so I can start installing insulation and vapor barriers during winter without trapping moisture underneath. Especially the vapor barrier in the basement needs to be done by the end of December, since plumbing and heating installation will begin in mid-January.
- Installing windows only next year is not an option for me because installation isn’t possible below 2°C (36°F), and the heating technician wants to start in January. Also, I want to carry out the electrical installation myself comfortably over the winter. Without windows, it’s 1) very cold and drafty inside and 2) I really cannot leave tools inside the house.
What will I do now? I will rent a construction dryer for 1–2 weeks to dry things out somewhat in advance. Hopefully, occasional airing by opening windows will take care of the rest. This way, I won’t have to worry about mold.
Best regards and thanks again for all the tips.
XxTankerxX
Thanks for your opinions.
Just to clarify:
- No screed or plaster has been applied in the house yet, and this won’t happen before April next year.
- My main goal is to remove the rough moisture so I can start installing insulation and vapor barriers during winter without trapping moisture underneath. Especially the vapor barrier in the basement needs to be done by the end of December, since plumbing and heating installation will begin in mid-January.
- Installing windows only next year is not an option for me because installation isn’t possible below 2°C (36°F), and the heating technician wants to start in January. Also, I want to carry out the electrical installation myself comfortably over the winter. Without windows, it’s 1) very cold and drafty inside and 2) I really cannot leave tools inside the house.
What will I do now? I will rent a construction dryer for 1–2 weeks to dry things out somewhat in advance. Hopefully, occasional airing by opening windows will take care of the rest. This way, I won’t have to worry about mold.
Best regards and thanks again for all the tips.
XxTankerxX
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XxTankerxX23 Nov 2021 22:45Alessandro schrieb:
I would still use a dehumidifier as well.
Is the hatch to the top floor ceiling/attic closed? It is obviously still open at the moment. The shell construction has just been completed.
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Alessandro25 Nov 2021 08:09XxTankerxX schrieb:
It is obviously still open at the moment. The shell construction has just been completed.Make sure to close it definitely before the plaster and screed are installed in the house.
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