I can't tell you specifically what kind of point change you'll see, but most certainly your score will go up and not down. Mortgages are looked at more positively than a line of credit. I'm sure someone else will chime in that can be more specific with data points.
You don't mention your current scores or the rest of your profile (cars, student loans, credit cards) which is probably part of the equation - for instance if your construction loan is the only thing on your credit report then it's going to cause some more drastic or unusual results.
