GDS, TDS, LTV, PIT, & 6 'C's

Genworth Financial are the people to talk to, or at least for your lenders to talk to, when you're purchasing a home and have less than 20% as a downpayment.
Dominion Lending Centres invited myself, and other Royal LePage Triland reps in the area, to attend a quick 2-hour fast-paced seminar about high ratio mortgages and the underwriting insurance purchased on same.
Keep in mind, that federal regulations now stipulate that when you become pre-qualified or pre-approved for a mortgage, it will be suggested how much of a house you can buy based on the current 5-year fixed rate, which could be the difference of 1.8% as some good customers (good beacon scores on a credit check) can qualify for a variable rate under 2.25 currently.
The six 'C''s discussed were character, collateral, capital, credit, capacity and common sense.
A client's credit history is obviously a benchmark -- your repayment of all loans, including students loans, credit cards, borrowing for a vehicle, and even paying off that couch and chair you purchased over time from a large furniture store.
The better the beacon score on a credit check -- the more solid a client you are. I'm not sure how all the numbers fall together, but the score to attain is 680 or higher to be considered a very low risk customer.
When combined with your family's annual income, the amount you can afford for monthly payments is calculated, and thereby the amount you can afford to pay back in a total mortgage is tabulated.
There are two mathematical numbers. TDS is total debt service ratio, which includes principal, interest and taxes (PIT) on your house, but also factors in heating costs, a portion of condo fees (if any), car payments, credit card and other commitments. GDS is gross debt service ratio and that percentage can be as low as 32%, or 32% of your total income can be applied to PIT.
With 5% as a basic downpayment, Genworth Financial (or the federal agency known as CMHC) will underwrite an insurance cost on top of your mortgage total to protect the lending institution from a possible default by you.
LTV is the loan-to-value ratio -- the larger the downpayment as a percentage of selling price of the home, the less CMHC or Genworth insurance you would be required to pay.
This information covers just some of the basics. You could check out http://www.genworth.com/