Construction defects come in many different types. You can't look for only obvious defects when you are trying to make sure that your project is being handled in an appropriate manner. Instead, you need to be nitpicky so that you might be able to spot what is wrong before it becomes a huge problem for your project.
One of the common construction defects comes from inferior materials. When this happens, your project might be doomed from the start. You have to get to the bottom of why the materials aren't up to par. This might be because of an honest mistake, which should mean that the contractor takes steps to rectify the issue without any trouble. In other cases, this could be because the contractor got a good deal on low quality materials and tried to pass them off as acceptable for your project, which means you might have more trouble getting it all taken care of when you point out the issue.
Another common type of defect comes from less than ideal workmanship. This is something that a reputable contractor will happily address but one that isn't as reputable might not be willing to do anything about it. You have try your best to find a contractor who is willing to stand behind her work and put that guarantee in writing.
You do have the right to take action to recover your money or have your project corrected if you find construction defects. Even if the issue was with the planning of the project, you still have options. Make sure that you explore these so that you can have the outcome you desire for the case.
Source: Traveler's Insurance, "Types of Construction Defects," accessed March 21, 2018