If you have a door that you have to keep shutting because it just won't stay shut, it can be really frustrating. You can end up closing that door a million times a day, and the next time you turn around that door is open again. There are a lot of things that you can do to fix it so that you can get it to close and stay closed.
Check the Plumb and Level
One thing you need to do if your door won't stay shut is to check the level and plumb of your door frame. When you are talking about your house, level means something is straight on the horizontal, like your floor. This is measured by using a level, which is a tool that has a small tube with some liquid and a bubble in it. When the level is placed on the floor, the bubble should be right in between two markings on the tube. Plumb means that something is straight on the vertical, like your wall. There are a lot of ways to measure the plumb of your door frame. Some people use a level in the same way that they would measure level. However, you can also use something called a plumb line. This is basically a piece of twine with a small weight hung on the end. You can check the plumb by hanging the string from a level surface, for example, the top of your doorframe, if it is level. If the string hangs straight, then your door is plumb.
Check the Latches
Another thing you can do is make sure that the latches are on straight, tight, and at the right height. Your door may look like it's securely latching, but the latch could be just enough off that the door isn't really catching, so the door slips open again. You can check this by closing the door and looking at it when it's closed. You are looking to see if the part on the door goes firmly into the hole in the door frame. If it appears just a little bit off, then you may need to adjust the latch. First try tightening everything up to see if that works. If it doesn't, then you may have to adjust the part on the door a little, just to try and get the full thing to work.
A door that won't stay shut can cause a huge headache. There are things that you can do to try to fix the problem. Contact a door installation expert for more information.