Green roofs in WUFI 2D

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Green roofs in WUFI 2D

Post by olegh » Tue May 21, 2019 9:00 am -1100

I am simulating a case with a green roof using the Guideline for the calculation of extensive green roofs from WUFI.
In the green roof manual i see that you are supposed to add a moisture source in the substrate layer and set clipping to the source if it reaches free water saturation.

The problem is that i cant see any clipping criteria in moisture sources in WUFI 2D.
The calculation completes, but i see that i get quite a few convergence failures. I am guessing these convergence failures is due to the substrate layer getting oversaturated.

What i am wondering is if these convergence failures will have a big impact in the moisture content inside my roof. If the failures are only due to the substrate layer getting saturated, my thought is that this won't have that a big impact of what is actually happening inside the roof.

Thanks for feedback

Christian Bludau
WUFI SupportTeam IBP
WUFI SupportTeam IBP
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Re: Green roofs in WUFI 2D

Post by Christian Bludau » Wed Nov 13, 2019 9:50 pm -1100

Hi Olegh,
sorry for the late answer.
Both WUFI Pro and 2D show a lot of convergence problems calculating a green roof due to the high amount of water in the substrate.
Have a look on the courses of the water content below the roofing felt. If the courses act like expected, you usually can accept the convergence failures. If you get noticeable jumps or unexpected courses in the water content, be careful.

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