Short answer
The lender does not automatically increase the mortgage because costs rose. You may need cash, approved additional financing, a reduced scope or a revised appraisal and underwriting review. Waiting until the builder stops work leaves fewer choices.
The client problem behind the question
Unexpected excavation, permit and material costs consume the contingency before the project reaches the lender’s next draw stage.
What the official guidance establishes
Ontario building permits authorize regulated work but do not guarantee its cost. Mortgage approval is based on an accepted budget, borrower capacity, security value and lender conditions.
Where the answer can change
A new loan or second mortgage can alter priority, loan-to-value and the first lender’s approval. Alternative, MIC or private funding may bridge a defined shortfall, but fees and interest can compound during delays. The exit must work after the project is complete.
A practical Ontario example
Illustration only: A build is $90,000 over budget at lock-up. The owner has strong finished value but no liquidity. A short-term second mortgage may complete the work, provided the first lender consents and the completed refinance can repay it.
What to do before committing
Report overruns immediately. Update the cost-to-complete report, remaining draws, appraisal, contractor schedule and contingency. Compare scope reduction, family equity, an approved secured facility and short-term financing before work stops.
Questions Rajiv would ask
- What deadline, condition or closing problem must be solved?
- Which facts are confirmed by original documents and which are still assumptions?
- Which law, insurer rule or lender policy applies to this exact transaction?
- What happens to the cash requirement and monthly payment if the first option fails?
- What is the practical route back to lower-cost financing, if temporary financing is used?
Rajiv’s broker perspective
I would match the financing to the contractor schedule, not only to the finished value. The practical review includes how much cash is needed before each draw, whether permits and rent are supportable, and what happens if the project costs more or takes longer. A, alternative/B, MIC and private options can each work, but the exit and total cost must be clear before construction begins.
Related: Mortgage declined? Start here · Mortgage Knowledge Centre · Real Estate Centre · Updates & Rules Centre
Would a second opinion help before you commit?
Send Rajiv the property, deadline, financing concern and the documents already available. He can identify the missing questions, compare practical mortgage routes and explain the next step in plain language.