Hello everyone,
I have already searched the forum but couldn’t find anything relevant on this topic.
We are currently planning the energy-efficient renovation of our house built in 1980. One of the measures will be insulation of the exterior walls. We plan to install 10 cm (4 inches) of insulation (mineral-based insulation materials).
Now, a friend told us that he has a mold problem in his relatively small stairwell. In his opinion, this is because the underfloor heating installed there is not able to heat the space properly.
In our case, the stairwell has no heating at all. The stairwell is external, meaning it is outside the actual apartments and is open over three floors.
We are now considering installing, for example, a wall heating system in the stairwell to have the option to heat it if necessary.
Do you think this makes sense, or is heating unnecessary in a stairwell?
Also, do you see a risk of mold in an unheated stairwell?
Regards
I have already searched the forum but couldn’t find anything relevant on this topic.
We are currently planning the energy-efficient renovation of our house built in 1980. One of the measures will be insulation of the exterior walls. We plan to install 10 cm (4 inches) of insulation (mineral-based insulation materials).
Now, a friend told us that he has a mold problem in his relatively small stairwell. In his opinion, this is because the underfloor heating installed there is not able to heat the space properly.
In our case, the stairwell has no heating at all. The stairwell is external, meaning it is outside the actual apartments and is open over three floors.
We are now considering installing, for example, a wall heating system in the stairwell to have the option to heat it if necessary.
Do you think this makes sense, or is heating unnecessary in a stairwell?
Also, do you see a risk of mold in an unheated stairwell?
Regards
G
Gecko19272 Nov 2022 14:14Is your stairwell located inside or outside the thermal envelope?
How are the doors and walls leading to the stairwell designed?
It makes little sense to heat a stairwell that is outside and not insulated on the exterior side.
Basically, you have two options:
1. Integrate the stairwell within the thermal envelope (insulate the exterior wall – use insulated windows) and heat it.
2. Keep the stairwell outside the thermal envelope (insulate the interior wall, install entrance doors between the stairwell and the apartment(s)) and ensure that no warm, humid air from the apartment enters the stairwell.
You don’t need to heat a garage to keep it free of mold, but in that case, no condensation forms due to warm air coming from the living space.
How are the doors and walls leading to the stairwell designed?
It makes little sense to heat a stairwell that is outside and not insulated on the exterior side.
Basically, you have two options:
1. Integrate the stairwell within the thermal envelope (insulate the exterior wall – use insulated windows) and heat it.
2. Keep the stairwell outside the thermal envelope (insulate the interior wall, install entrance doors between the stairwell and the apartment(s)) and ensure that no warm, humid air from the apartment enters the stairwell.
You don’t need to heat a garage to keep it free of mold, but in that case, no condensation forms due to warm air coming from the living space.
In our case, option 1 applies (1. Integrate the stairwell into the thermal envelope by insulating the exterior wall and installing insulated windows, and provide heating).
The doors leading to the stairwell are standard apartment doors, meaning they are not specially insulated. The exterior wall of the stairwell is insulated just like the rest of the house. The front door will be replaced, and existing glass blocks will also be replaced.
The only difference is that the stairwell does not have its own heating system and would only be warmed by air from the living area.
The doors leading to the stairwell are standard apartment doors, meaning they are not specially insulated. The exterior wall of the stairwell is insulated just like the rest of the house. The front door will be replaced, and existing glass blocks will also be replaced.
The only difference is that the stairwell does not have its own heating system and would only be warmed by air from the living area.
Flitz86 schrieb:
In our case, option 1 applies (1. Integrate the stairwell into the thermal envelope by insulating the exterior wall and upgrading the window insulation, and heating it).
The doors to the stairwell are standard apartment doors, meaning they are not specially insulated.
The exterior wall of the stairwell is insulated just like the rest of the house. The front door will be replaced, as will existing glass blocks.
The only difference is that there is no separate heating in the stairwell, so the room would only be warmed by air from the living area...This is predictably going to fail because the combination of options 1 and 2, as described by @Gecko1927, is not supported by the laws of physics. However, for such a renovation, I do see potential for financial incentives and thus recommend consulting an energy advisor. They would also point out relevant options and potential risks.i_b_n_a_n schrieb:
This is bound to go wrong because the combination of 1 + 2, as described by @Gecko1927, is not supported by physics. I don’t understand this point? As I said, we will go with option 1, meaning the stairwell will be insulated the same way as the rest of the house.
This is part of an energy retrofit being carried out in cooperation with an energy consultant. So far, he has not specifically identified the stairwell as a risk or problem area. However, I will discuss it with him again...
Flitz86 schrieb:
I don’t understand the point? As I said, we are going with option 1, meaning the staircase will be insulated just like the rest of the house...only with the difference that there is no heating ... (the storage capacity for water vapor in colder air is different from that in warm air) So, in my opinion, condensation from the warm indoor air will settle in the insulated but unheated staircase and lead to mold growth. Alternatively, moist air from outside can also cause this. But mold doesn’t care...
Maybe your accompanying energy consultant has a trump card up their sleeve? (ventilation system with humidity sensor?)
And as always: non-expert opinion
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