The City of Saskatoon's permit file is what a lender or appraiser checks first, looking for a building permit covering the secondary suite's egress, ceiling height and fire separation. A well-finished space without that paperwork still fails the test that determines whether the income counts.
Assuming the suite is legal, the exact amount added depends on the lender's own policy and where the rest of your file sits against a 39 percent gross debt service ratio and a 44 percent total debt service ratio, with a minimum insured-mortgage credit score of 600.
Confirming legality before you write an offer avoids discovering the problem during underwriting. Get your hand-reviewed valuation from Joel Dyck.