The Approval Illusion is the mistaken belief that a standard mortgage pre-approval guarantees you will receive funding when your pre-construction property closes. In reality, a pre-approval only indicates that you may qualify for a certain loan amount; your income, credit, and the property value must still meet the lender's conditions at the time of closing.
No. With 99.9% of lenders, you cannot access "paper equity" on closing day because lenders will advance funds based on the lower of the purchase price or the appraised value. Even if the property is worth more than you paid, the mortgage is calculated on the purchase price at closing.
You should seek a mortgage approval from the builder's on-site lender. Because this lender provided the construction loan and is familiar with the project, they are more likely to issue an actual mortgage approval rather than just a pre-approval, giving you peace of mind that financing will be available at closing.
The standard strategy is to take a variable rate mortgage at closing and then refinance the property after six months. At that point, if the appraised value has increased, you can access the equity through a refinance with most lenders.
If the appraised value is lower than your purchase price, the lender will base the mortgage on the appraised value, and you must cover the difference. You can bridge this shortfall by leveraging equity from other properties or by negotiating a vendor takeback mortgage with the builder.