A lender can issue a loan any time, at their own discretion, however in Alberta a consumer proposal stays on your credit report for 3 years after the proposal is completed and in general lenders will not issue a mortgage to someone until they have started to rebuild their credit rating.
Most creditors in Alberta will not approve you for a mortgage while you are in a proposal. You can renew a mortgage though, while in a proposal, but your interest rate may be affected. We often advise clients to renew their mortgages first before filing one.
During the proposal you can save towards the down payment and then apply for mortgage approval afterwards. If you have included a mortgage shortfall in a proposal or bankruptcy you may not qualify for further CMHC insurance in which case you will need a bigger deposit.
The ability to borrow money is based on your credit score, as well as your income, other debts, and your past financial history. The quicker you pay off your proposal, the sooner it will be purged from your credit report, which means paying off your proposal as fast as you can is the best way to rebuild your credit quickly.