Ventilated roof vs ventilated cavity wall

[Alberto Morales]

Hi,

I was reading the article about Hygrothermal Simulation of ventilated pitched roofs with effective transfer parameters and a question come out,

Why is ignored all layers above a ventilated air cavity in the roof as fraunhofer reconmends in the guideline "Handling of typical constructions"(including this one) but not for wall (toward the left side)?

is it due to ventilated roof at normal rates as recommended in the article is considered to be at the same condiitons than outdoors?

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Regards

[Christian Bludau]

Hi Alberto,

the outer layers are neglected in this pitched roof models because the influence of the ventilation and long wave radiation are simplified and expressed here by adopting the absorption, emission and heat transfer. This is based on measurements on different roofs.
We did not do such research/ models for cavity walls.

Regarding the cavity walls search the web for the work of Mundt-Petersen respectively Hägerstedt. He did a lot of research on ventilated wood frame walls.

Christian

[Alberto Morales]

Thanks a lot once again