No, you're not haunted: it's probably just banging pipes
At some point in your life, your house is going to start making noises. Perhaps you've just gotten into the shower, or are in the process of doing the laundry when you hear a loud banging noise coming from inside your home.
Could it be that your house is trying to speak with you? Are these threats from supernatural sources? Sadly, that's unlikely. The real reason is far more mundane: you've probably just got banging pipes.
What are banging pipes?
In your water lines, the water does not, in fact, flow smoothly. It tends to slosh and swirl at a relatively consistent pace.
This consistency is why it doesn't seem to be noticeable. The noise in your pipes does not emanate from here though; rather, it comes from the rapid closure of your valves, causing pressure transients in your water pipelines.
This pressure propelling the water, which now has nowhere to go, causes the pipes to flex. This is the reason for the banging sound.
How are banging pipes fixed in older buildings?
There are a number of ways banging pipes can be fixed in older buildings. These will depend on the cause and source of the banging pipes themselves. Most are fairly non-invasive and they aren't procedures that will take weeks out of your time.
1) Draining the building's water supply
This works on buildings that have air risers or vertical pipes. Draining the water from these pipes will allow air to be re-admitted into the riser pipe, thus causing the source of the banging to be rectified.
2) Use a water hammer arrestor
These can be bought at most hardware stores. What it does is maintain consistent levels of pressure within the pipes. It will be installed as close to the source of the noise as possible, and should hopefully rectify the issue.
3) Checking the water pressure
One of the biggest causes of banging pipes is water pressure that is too high. Check your water pressure, and if it's above 80psi then you're going to need to install a water pressure regulator to keep it at levels that won't cause the pipes to expand and make noise.
4) Ensure the pipes are secure
If your water pipes are loose, this gives a lot more room for them to succumb to that banging sound. This is because the looseness allows them excessive movement when water is running through. Tightly secure them, and you should solve the problem.
Can you prevent banging pipes?
There are a few methods of prevention against banging pipes. The first is to install valves that can only be opened and shut gradually. This is an excellent solution as it directly addresses the source of the problem.
Other ways you can prevent this disturbance is through your selection of air-vents. If the air is escaping too quickly, you have a high chance of ending up with banging pipes. So once again, gradual is key.
If you're still at the stage when you're installing the pipes, choose ones that restrict the water flow to 5 fps. With these measures, you can ensure that banging pipes are a problem that you'll never have to face.