Private mortgage insurance is required when you purchase a home with a down payment of less than 20% of the sale price or the appraised home value, whichever is less. Your lender in this case will expect you to purchase a private mortgage insurance policy so that even if you default, he can compensate for the loss. So when you make low down payment on your home purchase, you pay for the insurance premiums on a monthly basis till you can build up sufficient equity in your home.
You can avoid PMI premiums if you are approved for a piggyback mortgage loan. These loans involve 2 mortgages combined in the ratio of 80/20, 80/15/5 or 80/10/10. This implies that you take a first mortgage against 80% of your home value and second mortgage against the remaining 20% the property value.
Otherwise, you can opt for a first mortgage against 80% of the property value with a second mortgage worth 15% and make a down payment of 5% on the sale price. The third option is that you make a 10% down payment on the sale price and then go for a first mortgage of 80% along with a second mortgage loan against 10% property value.