ᐅ Heating-up phase of the screed / floor screed window position
Created on: 2 Dec 2021 07:10
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XAMMAX2
Good morning everyone,
I have a question:
Next week, after 6 weeks, the screed will be heated up at my place.
My question is, should the space be ventilated during the heating phase?
If yes, should I ventilate once a day by fully opening the windows or keep them tilted open continuously?
I would like to have my windows sealed off already so that the painter can apply the first coat at the end of the heating phase.
Thank you very much.
I have a question:
Next week, after 6 weeks, the screed will be heated up at my place.
My question is, should the space be ventilated during the heating phase?
If yes, should I ventilate once a day by fully opening the windows or keep them tilted open continuously?
I would like to have my windows sealed off already so that the painter can apply the first coat at the end of the heating phase.
Thank you very much.
Hausbau 55 schrieb:
The prospect of the required temperatures rising up to 60°C (140°F) flow temperature and holding there for three days is simply dreadful. Let me whisper this to you: Lower the temperature, shorten the heating-up phase according to your preferences, and you will soon experience far worse moments than a heating phase up to 60°C (140°F) — which understandably involves one-time costs.
Regards, KlaRa
H
Hausbau 552 Dec 2021 18:35KlaRa schrieb:
An interesting statement. Where does this information come from?
What exactly does “design for underfloor heating” mean? If the supply temperature for operational heating is set to 60°C (140°F), then the heating system must be designed accordingly.
How should the note "... is sufficient up to the design for underfloor heating" be understood? I have the heating-up protocol in hand. It specifies the required temperature profile: starting at 20°C (68°F) supply temperature, then 25°C (77°F), and increasing by 5 degrees per day up to 60°C (140°F). This maximum temperature is maintained for 3 days. After that, it is reduced in steps of 10 degrees. Then follow 2 rest days for the screed.
“If this recommendation is not followed and shorter heating-up phases are used, the warranty for the screed becomes void.” Excerpt from the heating-up protocol...
Our heating load calculation shows a maximum supply temperature of 33°C (91°F) under nominal operating conditions.
My comment referred to the one from "Motor Rotor," who posted:
"Why so high? Normally, it’s enough to go up to the design temperature of the underfloor heating. Maybe a few degrees more as a reserve, but 60 is really excessive."
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The heating-up protocol "Interface coordination for heated floor constructions" from the BVF is definitely appropriate.
By the way, it also states there "hold the maximum design temperature for at least 4 days."
My questioning remark was more aimed at the above-mentioned author’s opinion, which implied that you could choose "one level lower" (regarding the maximum temperature). No, that is not the case.
The way you described it (and obviously carried it out) is correct!
Please also remember that after the 2-day cool-down phase, the pre-conditioning heating is required shortly before installing the floor covering.
The functional heating currently being performed has nothing to do with the (necessary) pre-conditioning heating!
Just a note.
Regards, KlaRa
"Why so high? Normally, it’s enough to go up to the design temperature of the underfloor heating. Maybe a few degrees more as a reserve, but 60 is really excessive."
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The heating-up protocol "Interface coordination for heated floor constructions" from the BVF is definitely appropriate.
By the way, it also states there "hold the maximum design temperature for at least 4 days."
My questioning remark was more aimed at the above-mentioned author’s opinion, which implied that you could choose "one level lower" (regarding the maximum temperature). No, that is not the case.
The way you described it (and obviously carried it out) is correct!
Please also remember that after the 2-day cool-down phase, the pre-conditioning heating is required shortly before installing the floor covering.
The functional heating currently being performed has nothing to do with the (necessary) pre-conditioning heating!
Just a note.
Regards, KlaRa
R
RotorMotor2 Dec 2021 23:16KlaRa schrieb:
An interesting statement. Where does this knowledge come from?
What does design of underfloor heating mean, by the way? If the supply temperature for functional heating is set to 60°C (140°F), then the heating system must also be designed for that.
How should the note "... is sufficient up to the design of underfloor heating" be understood? Do you mean that 60 degrees (140°F) should also be reached during functional heating if the heating system will only ever reach a maximum of 35 degrees (95°F) in operation?
I have always read it differently so far. DIN 1264-4 also states an increase to the design temperature for 4 days.
KlaRa schrieb:
and after a short time you will have to endure much worse moments What exactly terrible thing is supposed to happen there?
F
FoxMulder243 Dec 2021 08:30Hausbau 55 schrieb:
I have the heating-up protocol in hand. It specifies the required temperature curve: start with 20°C (68°F) flow temperature, then 25°C (77°F), increasing by 5 degrees per day up to 60°C (140°F). This maximum temperature is to be maintained for 3 days. Then reduce in increments of 10 degrees. After that, allow 2 rest days for the screed.
"If this recommendation is disregarded and shorter heating phases are used, the warranty for the screed becomes void." Excerpt from the heating-up protocol...
Our heating load calculation states a maximum flow temperature of 33°C (91°F) for the heat pump under average conditions. We had a similar heating-up protocol for our liquid screed. Luckily, the heat pump only occasionally activated the electric heating element, even though it was winter with snow outside.
But make sure to ventilate by fully opening the windows 2-3 times a day!
Tilted windows lose a lot of heat but let in relatively little fresh (dry) air.
This ventilating method was also explicitly mentioned in our protocol.
Especially at the beginning, and when the maximum temperature is reached, a significant amount of moisture comes out of the floor.
"I have always read it differently until now. DIN 1264-4 also specifies heating up to the design temperature for 4 days."
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Well, the DIN EN 1264 even in the updated version from 08/2021 only sets out the uniform requirements for planning and construction.
It has nothing to do with functional heating and temperature steps. Hence, also nothing with the readiness heating of the screed and the associated background here.
Currently, only the interface coordination from the Federal Association for Surface Heating contains the up-to-date rules on how, how long, and with which time phases a new heated screed must be heated to which temperature.
The purpose is, on the one hand, during functional heating, to check whether all components within the installed heating system are working correctly. To prevent the young screed from cracking due to thermal stress, gradual, cautious heating is necessary.
The readiness heating, which must be done after cooling down, serves other purposes.
If the specifications that represent the state of the art and the professional rules are not followed, there is a high risk that the screed will be damaged.
The somewhat sarcastic question "What terrible thing could possibly happen?", I can gladly answer as well.
If readiness heating, as well as the preceding functional heating, are not operated at the maximum possible flow temperature, screed readiness can still be achieved. However, due to the greater screed thickness between the heating elements, it will not be reached within the required timeframe.
This means that, when laying the floor covering, the screed will not have the necessary dryness throughout its cross-section.
With a later rigid surface covering, such as ceramic tiles, the time-dependent natural drying will cause internal stresses in the screed structure, which (with sufficient certainty) will lead to cracks, sometimes accompanied by height differences along the crack edges.
This type of damage can only be repaired by removing all furniture and completely taking up the surface covering.
No, this is not "mere theory" but my lived professional experience in a sufficient number of cases over the last 35 years!
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I hope I was able to explain this clearly.
Best regards, KlaRa
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Well, the DIN EN 1264 even in the updated version from 08/2021 only sets out the uniform requirements for planning and construction.
It has nothing to do with functional heating and temperature steps. Hence, also nothing with the readiness heating of the screed and the associated background here.
Currently, only the interface coordination from the Federal Association for Surface Heating contains the up-to-date rules on how, how long, and with which time phases a new heated screed must be heated to which temperature.
The purpose is, on the one hand, during functional heating, to check whether all components within the installed heating system are working correctly. To prevent the young screed from cracking due to thermal stress, gradual, cautious heating is necessary.
The readiness heating, which must be done after cooling down, serves other purposes.
If the specifications that represent the state of the art and the professional rules are not followed, there is a high risk that the screed will be damaged.
The somewhat sarcastic question "What terrible thing could possibly happen?", I can gladly answer as well.
If readiness heating, as well as the preceding functional heating, are not operated at the maximum possible flow temperature, screed readiness can still be achieved. However, due to the greater screed thickness between the heating elements, it will not be reached within the required timeframe.
This means that, when laying the floor covering, the screed will not have the necessary dryness throughout its cross-section.
With a later rigid surface covering, such as ceramic tiles, the time-dependent natural drying will cause internal stresses in the screed structure, which (with sufficient certainty) will lead to cracks, sometimes accompanied by height differences along the crack edges.
This type of damage can only be repaired by removing all furniture and completely taking up the surface covering.
No, this is not "mere theory" but my lived professional experience in a sufficient number of cases over the last 35 years!
----------------------
I hope I was able to explain this clearly.
Best regards, KlaRa
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