Microsoft Project 2013

Hi Rufus

Weekends are normally non working time in Project.
If you need to change or check this this go to
Project (tab)
Change Working Time
Click the Work Weeks tab then Details button.
Select Saturday and Sunday
Click Set dates to non working time.

This will make the weekends non working.
Also check that the Options is set correctly
40 hours per week
5 days per week
20 days per month.

Hope that answers your query?

Regards
Doug Dunn
Best STL