A dream about a demolition usually symbolizes an important change in your life. Something old is being destroyed in order to make room for something new.
If someone else is performing the demolition, you feel that you do not have any control over the changes that you are experiencing.
However, if you are demolishing something yourself, you want to take an active part in changing your life for the better.
Demolishing something in a dream can also be a way of releasing anger that you are repressing in real life.
You may demolish something in a dream when you have too much stress in your life and you are worried that if you allow your emotions to escape, they will be destructive.