WUFI

We speak about dew water which condenses inside the insulation foam - your question was about interstital condensation. This cannot runoff.
Other moisture cannot enter the insualation but at most condense on the surfaces.

In close-cell insulation no runoff can occur. The water remains in the cells where it forms.

If necessary, an increase in thermal conductivity should be taken into account—as a general guideline, one can assume that for water contents up to 2% by volume or 20 kg/m³, the effect of moisture is ...

Hallo HD-Kutscher,

geht es nur um die thermische Masse des Sandes? Oder kann der feucht werden?

Die Sand-Parameter aus der US-Datenbank können sie für thermische Fragen vermutlich gut heranziehen. Wenn es wirklich um Beregnung, Feuchterückhaltung und Verdunstung geht, bin ich nicht sicher, ob ...

Dear l.clapham,

for an impregnation of a brick wall, an A value of 0,1 kg/m²√h is recommended for example according to WTA-Guideline 3.17. So this is OK.

In the mentioned WUFI example, just an example of 0,5 kg/m²√h was used, because this is another requirement according to the German standard ...

Dear Alberto,

you're right, that does not look very good.

The steep vertical increases in water content are obviously not correct. However, in the total balances these problem remain unvisible - this may be because the issue is simply a slightly incorrect distribution of moisture within the ...

Dear Alexandre,

an additional information: you shouldn't limit the moisture content in fibre insulation by g/m³, but rather by percent by mass (which is, however, rather unreliable), or better yet to a level of RH – best based on susceptibility investigations of the material. Unfortunately, there ...

Thanks for the reply. I really appreciate it.

when I want to calculate the final conditions (water content) of the original wall (just stone wall and render) which will be the initial conditions of the proposed wall (with interior insulation), do I also need to set an air leakage rate (q50) on ...

Dear Alberto,

you can introduce a 1 % rain source and check what is happening. However, cracks at the window will lead to local moisture entry - and problems around the window, but not to moisture entry in the middle of the wall.

If there are cracks or the rain protection of the render is too ...

Hi Alberto,

1- Should I add 1 % of driving rain? if yes, where should I place it? In the outermost 5mm of the render in contact with external ambient?
ANSWER: No - this is only used in case of EWIS / EIFS or facade claddings, where rain can run behind the most exterior layer, but not for rendered ...

Hallo Herr Ansari,

ich vermute, dass die Schalung unter der V13 im Wesentlichen die Gleichgewichtsfeuchten zur Außenluft – einschließlich einer gewissen Unterkühlung der Eindeckung – bekommt. Sprich: Die Feuchtegehalte würden sich vermutlich sehr ähnlich einstellen, wenn Sie nur eine Schalung mit ...

Weitere Informationen gibt es im Projektbericht - aber das Thema wird aktuell auch noch weiter bearbeitet:
https://wufi.de/de/wp-content/uploads/s ... ericht.pdf

More information can be found here - but the topic is still ongoing:
https://wufi.de/de/wp-content/uploads/s ... Report.pdf

Dear Alexandre,

This is not an easy question to answer. According to CSTB SimHuBat 7.6 (in France), 23% moisture content is permissible for non-load-bearing wood-based materials.

Until now, the WTA curve has actually been intended for softwood. However, many wood fiber insulation materials are ...

Hallo Herr Hartmann,

dieses Bewertungskriterium ist im Moment ein bisschen in der Schwebe. Nach WTA gilt die dortige Grenzkurve nur für Massivholz.

Neuere Forschungsergebnisse wie z.B. ThermNat zeigen allerdings, dass viele der dort untersuchten Holzfaserdämmstoffe genauso oder sogar beständiger ...

Dear Alexandre,

this is not an easy question to answer. According to CSTB SimHuBat 7.6, 23% by mass is permissible for non-load-bearing wood-based materials in France.

Until now, the WTA curve has actually been intended for softwood. However, many wood fiber insulation materials are even more ...