@osbornedj
Section 280A provides that a day of personal use does not include any day that the taxpayer is engaged in repair and maintenance on a substantially full time basis for any day.
See https://www.law.cornell.edu/uscode/text/26/280A
Therefore, you have to examine your involvement in repairs and maintenance on a day-to-day basis. For instance, if you spent 40 hours working during a certain Monday-Friday period that does not necessarily mean you have 5 days of personal use. You could have put in 10 hours of work each day on Monday-Thursday, which would make Friday a day of personal use.
Further, provided you worked doing repairs and maintenance on the property, substantially full time, on any given day, it is irrelevant that other members of your family were using the property for personal use on those days.
