hometips.gregvan.com books.gregvan.com Every time that a plumber notches or drills a hole into a floor joist it weakens the floor and if this can be avoided, it should be. If you’re planning on framing a house or building a room addition and you need to install some plumbing pipes in the floor, it wouldn’t be a bad idea to watch this video. Poor planning can lead to big problems while building homes or remodeling them.