Adding numbers from text onto a date

Hi lifesavers!

I am writing a report where my people have used a text field to state the number of days for an audit to last.

I am trying to develop a schedule that shows AUDIT START DATE + number of days in text field (can range from .5 - 30), but I cant get SSRS to recognize the text as a number to add to the date.

I have tried to use:

=Fields!AuditStartDate.Value + Val(Fields!AuditDays.Value)

But this comes up with an error. All I need to be able to do is add the number written in a txt field to the audit start date which will give me a planned audit end date.

Can anyone please help me?

Thanks :)