Green roof, moisture source, why?
Green roof, moisture source, why?
According to the different guideline documents provided by WUFI, green roofs (generic and specific systems) shall be modelled with a moisture source in the lower part of the sedum system. What is the added value of modelling the moisture source, in addition to the rain that is included via the outside climate data? What is the difference between the moisture provided by the climate data rain and the moisture provided by the moisture source? Do these two affect the structure differently? (I use both WUFI 6 and WUFI 2D.)
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Christian Bludau
- WUFI SupportTeam IBP
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Re: Green roof, moisture source, why?
Hi Katrine,
with rain from the outside, the surface takes up water corresponding to the available pore volume and rain. This is redistributed into the construction depending on the liquid transport coefficients of the other layer. There is no seepage flow. A source is bringing in an additional fraction of the rain at the position the source is placed.
The green roof models are adapted so that the temperature at the roofing felt level in particular is adjusted correctly. This can be achieved by ensuring sufficient water content in the substrate. And to ensure that sufficient water is introduced during rainfall, a source is additionally used here. This replaces the water that would actually seep through in reality.
Christian
with rain from the outside, the surface takes up water corresponding to the available pore volume and rain. This is redistributed into the construction depending on the liquid transport coefficients of the other layer. There is no seepage flow. A source is bringing in an additional fraction of the rain at the position the source is placed.
The green roof models are adapted so that the temperature at the roofing felt level in particular is adjusted correctly. This can be achieved by ensuring sufficient water content in the substrate. And to ensure that sufficient water is introduced during rainfall, a source is additionally used here. This replaces the water that would actually seep through in reality.
Christian