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Do you know why my new finished basement foundation wall option is not saving?

asked 2019-09-07 20:03:22 -0600

skrucial gravatar image

updated 2019-09-07 20:03:41 -0600

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I installed 4" xps outside of the existing brick and field-stone foundation to 8" below the level of the new slab and an error was generated as i attempted to provide such an option. (The continuous exterior isocyanurate extends to the bottom of the first floor assembly).

the basement also has 2" xps below the slab but my slab option when away when i changed to finished basement.

Moreover, why is it asking for ceiling joist spacing in the foundation wall option manager?

Thank you so much for all of this software!!!

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answered 2019-09-10 16:13:21 -0600

updated 2020-10-26 09:22:12 -0600

I can reproduce the issue, it's a bug in BEopt that only seems to affect this category.

Unfortunately there is no easy way to workaround the issue -- the best advice is to pick the closest option (or do two multiple runs with different options and interpolate/extrapolate).

(The ceiling joist height is an input used in conjunction with the rim joist insulation.)

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answered 2020-10-26 09:36:48 -0600

jpierce gravatar image

updated 2020-10-26 09:43:09 -0600

I'm not sure why it cannot be saved, but note that Continuous Insulation Nominal R-value is total R, not R/in, so your entry should be 20 not 5. The Whole Wall R-20 XPS is probably your best bet. As for ceiling spacing values, those are so that it can calculate how much of the rim joist is thermal bridging to the floor versus exposed/insulated.

BEopt's Slab entries are for slab-on grade. Since the ground's temperature below the frost-line/in a basement is relatively constant compared to the ambient temperature, the software simplifies inputs and ignores under-slab insulation. This is a fairly reasonable simplification unless you have radiant heating in the slab, which BEopt itself does not explicitly handle anyhow.

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Asked: 2019-09-07 20:03:22 -0600

Seen: 337 times

Last updated: Oct 26 '20