Try using numeric values for your number of floors.
You can't mix numbers and strings unless you convert them to the same data type.
This will give you a numerical value that you can round up or down and multiply by your floor area.
You need to make sure that your expression will calculate the data type that you have set.
i.e. number, integer, length, etc.
A length multiplied by a length will give you an 'Area' data type, not a length.
If the expression is red, then the wrong data type is set, or you need to do a conversion in the expression to change it to the required data type.
Barry.
One of the forum moderators.
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