The maximum you can afford to spend on a house purchase is not always the amount you have been preapproved for. You can take steps to raise your mortgage preapproval amount if you believe your finances can support a larger mortgage. This is how: Find a co-borrower or co-signer. Boost your credit rating Increase your revenue Clear other obligations  Increase your down payment.  Speak to a different lender You may be able to examine a wider choice of homes if you have a higher preapproval amount.