ᐅ Are Cold Corners Still Acceptable in New Construction Today?

Thank you! Is the 1-degree difference measured by you, or is 1 degree a general target that should be achieved?

Measured when it was really cold.

May I quickly ask about the construction method of the house? Solid construction with or without external insulation / render / brick veneer?

BeHaElJa schrieb:
With monolithic construction, the ceiling must then be installed with insulation strips, or how does that work? Actually an interesting question – also regarding lintels.

The (concrete) ceiling does not rest completely on the walls, but only partially. From the outside to the inside, as far as I know, it looks like this:
- Perimeter ceiling blocks (to provide a uniform plaster base on the outside), e.g. 115mm (4.5 inches)
- Insulation, e.g. 110mm (4.3 inches)
- Concrete ceiling with bearing surface, e.g. 200mm (7.9 inches)
= Total thickness 425mm (16.7 inches)

For lintels, search for insulated lintels or load-bearing roller shutter boxes, and the principle should become clear. Of course, I don’t know if everyone building monolithically implements this properly. I also don’t think there are any regulations requiring it.

The external corner exposed to the weather on two sides is a geometric thermal bridge. The heat transfer coefficient of the wall at this point is calculated to be less favorable because the wall thickness, measured diagonally at the external corner, increases, which also raises the heat flow passing through the wall. Referring to 1m² (10.8 sq ft) of interior wall surface in the corner, a larger amount of heat is released than through the same interior wall surface of a normal exterior wall. Depending on the wall material used, the difference ranges between 25-40%.

It becomes problematic when the so-called "dew point" is undershot at these locations. This is the temperature at which water vapor from the warm, moist indoor air condenses on cold surfaces. For example: a cold mineral water bottle taken from the fridge onto the summer terrace causes condensation droplets to form. The specific dew point depends on the indoor air temperature and the amount of moisture contained (relative humidity). Under standard indoor conditions of 21°C/55% relative humidity, the dew point is about 11.6°C (53°F), while at 21°C/75% it is around 16.4°C (61.5°F).

Normally, the temperature on the inside surface of the exterior wall should only be 2-3°C lower than the indoor air temperature (comfort factor). At roughly 18°C (64°F) for the wall surface, a 25% reduced surface temperature in the corner situation corresponds to about 13.5°C (56°F). At this point, the dew point will be undershot at relative humidity levels of 60%-65%. These climatic conditions can be quickly reached in winter with insufficient ventilation or inadequate moisture removal. As a result, condensation forms and, in the long term, mold growth can occur.

Determining your specific situation can only be done if the wall building material, wall thickness, and construction details are known. New buildings must comply with the requirements of the energy saving regulations for heat-transferring exterior components. The external corner will always be cooler here as well, unless additional thermal insulation is applied to specifically mitigate this issue.

In general, surface temperatures of walls insulated according to energy saving regulation requirements do not fall into this critical range under average indoor climatic conditions. However, occupant behavior plays a significant role here (heating/ventilation/room furnishings + furniture).

Very interesting post...
From what I understand, a composite system would be preferable in this regard?