When you are looking to rehab a home be sure to inspect the foundation carefully or it can cost you alot to repair. Some serious problems to look for are cracked foundation walls, this could indicate a failing foundation which could affect the integrity of the entire home. Another thing to look for is crumbling mortar joints, these will need to be addressed to prevent damage to the home. Also keep an eye out for saw dust, which could indicate a ant or termite infestation in walls. Also be on the look out for water seepage and penetration as well.