Sloped and weak floor

[Ali Allen]

Hi!

We are new investors looking for our first home to flip. We found a property that we are interested in acquiring but we are hesitant because the floors are sloped and weak in some areas of the house. The home was built in 1910. It's a bungalow on a large crawl space. Most of of the sloping occurs in the area of the home that is an addition. There is some sloping in other areas as well though. 

Is this a major repair? What type of budget should be set for a job of this nature?

Thanks in advance for all your help! :)