ᐅ Cement screed with underfloor heating not drying any further?!
Created on: 14 Dec 2017 09:00
C
Cara-Sol
Hello,
I am a client from Schleswig-Holstein and absolutely desperate.
Apart from having very little knowledge about screed, I want to reach out to you with my problem:
Since summer, we have been building a small detached house (135 sqm (1453 sq ft), solid construction).
On October 17, 2017, our cement screed was installed (6 cm (2.4 inches) thick). We have underfloor heating throughout the house.
After 2 days, we were allowed to walk on the screed, and after one week, we started ventilating (opening windows fully for 10 minutes every morning and evening).
Since November 15, 2017, the underfloor heating’s drying program has been running, and every time we ventilate, we wipe the moisture from the windows, concrete ceiling, and doors with towels.
Since November 16, 2017, a large construction dryer has been running, and since November 23, a second smaller construction dryer (one on the lower floor, one on the upper floor).
On December 4, 2017, residual moisture in the screed was measured at 2.8% (unfortunately only in one spot). This was a CM measurement. After that, we started painting and plastering the walls (which may have introduced moisture again?).
On December 11, 2017, measurements were taken again, using the same method in several rooms on both floors, showing varying values between 2.7% and 3%.
We are so desperate! We have to leave our apartment by the end of December, and we have already had to postpone kitchen and staircase installation until early January. This means we will probably move in on December 31, 2017, without a staircase, kitchen, or flooring.
On the upper floor, carpet will be installed (with adhesive/fixation), and downstairs vinyl flooring (with leveling compound/adhesive), which we will do ourselves.
But we will never reach 1.8%!!! Many say it should have been dry by now... The screed installer told us this is strange and advised us to close everything for three days soon, keep the construction dryers and heating on, and not enter the house.
Could the screed have suffered a so-called “capillary break”? We are very afraid of this!
What have you done, how did you dry it, and what were your moisture measurements?
I would be grateful for any small help or advice!
Best regards,
Cara
I am a client from Schleswig-Holstein and absolutely desperate.
Apart from having very little knowledge about screed, I want to reach out to you with my problem:
Since summer, we have been building a small detached house (135 sqm (1453 sq ft), solid construction).
On October 17, 2017, our cement screed was installed (6 cm (2.4 inches) thick). We have underfloor heating throughout the house.
After 2 days, we were allowed to walk on the screed, and after one week, we started ventilating (opening windows fully for 10 minutes every morning and evening).
Since November 15, 2017, the underfloor heating’s drying program has been running, and every time we ventilate, we wipe the moisture from the windows, concrete ceiling, and doors with towels.
Since November 16, 2017, a large construction dryer has been running, and since November 23, a second smaller construction dryer (one on the lower floor, one on the upper floor).
On December 4, 2017, residual moisture in the screed was measured at 2.8% (unfortunately only in one spot). This was a CM measurement. After that, we started painting and plastering the walls (which may have introduced moisture again?).
On December 11, 2017, measurements were taken again, using the same method in several rooms on both floors, showing varying values between 2.7% and 3%.
We are so desperate! We have to leave our apartment by the end of December, and we have already had to postpone kitchen and staircase installation until early January. This means we will probably move in on December 31, 2017, without a staircase, kitchen, or flooring.
On the upper floor, carpet will be installed (with adhesive/fixation), and downstairs vinyl flooring (with leveling compound/adhesive), which we will do ourselves.
But we will never reach 1.8%!!! Many say it should have been dry by now... The screed installer told us this is strange and advised us to close everything for three days soon, keep the construction dryers and heating on, and not enter the house.
Could the screed have suffered a so-called “capillary break”? We are very afraid of this!
What have you done, how did you dry it, and what were your moisture measurements?
I would be grateful for any small help or advice!
Best regards,
Cara
K
Knallkörper15 Dec 2017 08:28I don’t see any issues caused by the weather. However, you will need to ventilate much more often than twice a day, and the interior should be kept warm, around 25 degrees Celsius (77°F). Drying fans help a lot at night, even if they only remove 5 or 10 liters (1-2.5 gallons). Given how you have dried so far, the duration is quite normal. It is probably too late for good advice now anyway, as from this point until around mid-January, almost no work will take place on the construction site. As already mentioned, your schedule is far too tight. Under these circumstances, fast-setting screed should have been used. It is ready for covering in 2-3 weeks and offers other advantages as well.
R
readytorumble15 Dec 2017 10:36I agree completely. Heat the space and ventilate much more frequently.
Every 3 hours, create a strong cross breeze for 5-10 minutes.
If you only ventilate in the morning and evening, meaning no ventilation throughout the entire day, it’s obvious that drying will be very slow. The weather is not to blame.
Every 3 hours, create a strong cross breeze for 5-10 minutes.
If you only ventilate in the morning and evening, meaning no ventilation throughout the entire day, it’s obvious that drying will be very slow. The weather is not to blame.
Hello Cara.
All previous comments on this topic each have their own valid points.
However, we do not yet know HOW the CM measurement was carried out.
Do you have information on the sample weight (in grams), the pressure reading from the manometer (in bar), and do you know from what depth within the screed the sample was taken?
All of this would take too much time now to investigate the possible cause.
Please do the following:
We need 2 hygrometers and 1 thermometer!
One should be placed (or hung) in the room, the other placed somewhere on the screed. We will now wrap the last hygrometer with a slightly thicker PE film measuring about 50cm x 50cm (20 inches x 20 inches) and seal the edges of the film firmly (!) to the surface of the screed using strong tape.
You will then have a square piece of film lying in front of you, and the second hygrometer will be placed in the center under the film.
After about 24 hours, note the reading on hygrometer 1 and measure the room temperature.
First, check under the film to see whether any condensation has formed. If YES, then there is no need to continue with this procedure because the screed is still wet (not just damp).
If there is no condensation, read the value displayed by the enclosed hygrometer!
If the value is over 70% to 75% relative humidity, then there is excessive residual moisture in the screed.
Based on the amount of water the drying system (if operating on the condensation principle) removes daily, you can also get a rough estimate of whether the target moisture level is being approached.
Please let us know how things look tomorrow or the day after!
------------------------------------
Regards, KlaRa
All previous comments on this topic each have their own valid points.
However, we do not yet know HOW the CM measurement was carried out.
Do you have information on the sample weight (in grams), the pressure reading from the manometer (in bar), and do you know from what depth within the screed the sample was taken?
All of this would take too much time now to investigate the possible cause.
Please do the following:
We need 2 hygrometers and 1 thermometer!
One should be placed (or hung) in the room, the other placed somewhere on the screed. We will now wrap the last hygrometer with a slightly thicker PE film measuring about 50cm x 50cm (20 inches x 20 inches) and seal the edges of the film firmly (!) to the surface of the screed using strong tape.
You will then have a square piece of film lying in front of you, and the second hygrometer will be placed in the center under the film.
After about 24 hours, note the reading on hygrometer 1 and measure the room temperature.
First, check under the film to see whether any condensation has formed. If YES, then there is no need to continue with this procedure because the screed is still wet (not just damp).
If there is no condensation, read the value displayed by the enclosed hygrometer!
If the value is over 70% to 75% relative humidity, then there is excessive residual moisture in the screed.
Based on the amount of water the drying system (if operating on the condensation principle) removes daily, you can also get a rough estimate of whether the target moisture level is being approached.
Please let us know how things look tomorrow or the day after!
------------------------------------
Regards, KlaRa
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