I have been paying khums from the last 2 years but this year when my date came I was in debt so I didn't.
Now its been 6 months and I am earning well. My dream is to build a house for my parents because we have a very small house.
Is it compulsory to pay khums when there is a need to build a house.

If the house you are living in does not meet your needs, and you are in desperate need for a bigger house, then you do not have to pay the khoms of that house.