If Excel has WORKDAY.INTL function, this will work. This does not count the start date . If you want to include the start date, add 1 to the result.

Formula: copy to clipboard 
=WORKDAY.INTL(A1,27,11,H1:H15)


A1 is the start date (change to suit your data)
27 is the number of workdays to add to the start date
11 fixes Sunday as the weekend
H1:H15 a range for holiday dates.