What You Need To Know About Co-Signing A Mortgage

Darrell McCollom • February 5, 2025

So you’re thinking about co-signing on a mortgage? Great, let’s talk about what that looks like. Although it’s nice to be in a position to help someone qualify for a mortgage, it’s not a decision that you should make lightly. Co-signing a mortgage could have a significant impact on your financial future. Here are some things to consider.


You’re fully responsible for the mortgage.


Regardless if you’re the principal borrower, co-borrower, or co-signor, if your name is on the mortgage, you are 100% responsible for the debt of the mortgage. Although the term co-signor makes it sound like you’re somehow removed from the actual mortgage, you have all the same legal obligations as everyone else on the mortgage. When you co-sign for a mortgage, you guarantee that the mortgage payments will be made, even if you aren’t the one making them.


So, if the primary applicant cannot make the payments for whatever reason, you’ll be expected to make them on their behalf. If payments aren’t made, and the mortgage goes into default, the lender will take legal action. This could negatively impact your credit score. So it’s an excellent idea to make sure you trust the primary applicant or have a way to monitor that payments are, in fact, being made so that you don’t end up in a bad financial situation.

 

You’re on the mortgage until they can qualify to remove you.


Once the initial mortgage term has been completed, you won’t be automatically removed from the mortgage. The primary applicant will have to make a new application in their own name and qualify for the mortgage on their own merit. If they don’t qualify, you’ll be kept on the mortgage for the next term.


So before co-signing, it’s a good idea to discuss how long you can expect your name will be on the mortgage. Having a clear and open conversation with the primary applicant and your independent mortgage professional will help outline expectations.


Co-signing a mortgage impacts your debt service ratio.


When you co-sign for a mortgage, all of the debt of the co-signed mortgage is counted in your debt service ratios. This means that if you’re looking to qualify for another mortgage in the future, you’ll have to include the payments of the co-signed mortgage in those calculations, even though you aren’t the one making the payments directly.


As this could significantly impact the amount you could borrow in the future, before you co-sign a mortgage, you’ll want to assess your financial future and decide if co-signing makes sense.


Co-signing a mortgage means helping someone get ahead.


While there are certainly things to consider when agreeing to co-sign on a mortgage application, chances are, by being a co-signor, you'll be helping someone you care for get ahead in life. The key to co-signing well is to outline expectations and over-communicate through the mortgage process.


If you have any questions about co-signing on a mortgage or about the mortgage application process in general, please connect anytime. It would be a pleasure to work with you.


Darrell McCollum
By Darrell McCollom • October 28, 2026
On October 28, 2026, the Bank of Canada raised its key interest rate by 0.25%, bringing it to 2.5%. If you have a mortgage, are shopping for a home, or have a renewal coming up, this decision matters. Here is a plain-language look at what changed, why it happened, and what it could mean for you.
By Darrell McCollom • October 21, 2026
Porting Your Mortgage: What You Need to Know Before You Rely on It Porting a mortgage means transferring your existing interest rate, remaining term, and outstanding balance from your current home to a new one when you sell and buy again. While some lenders—especially big banks—make porting sound simple, the reality is that porting a mortgage is often complex and far from guaranteed . It’s not a magic solution, and it doesn’t mean you automatically get to keep your old mortgage on your new home. In many ways, porting a mortgage feels like applying for a brand-new one—often with more conditions . Here’s why. 1. You Still Have to Re-Qualify Even though you already have the mortgage, the lender will reassess you. If you: Changed jobs Moved to a new city Are on probation Switched industries or income types …the lender may decline the port. Your previous approval does not carry over automatically. 2. The New Property Must Be Approved The lender also reassesses the new property . Just because they accepted your previous home as collateral doesn’t mean they’ll approve the next one. Expect: A new appraisal A review of the property’s condition Scrutiny around marketability and value If the lender isn’t comfortable with the property, the port can fail. 3. Property Values Rarely Line Up Perfectly Most moves involve a price difference. Buying a more expensive home: You’ll likely need additional funds at a blended rate, which can increase your payment. Buying a less expensive home: You may face a penalty for reducing the mortgage balance. Either scenario can affect your costs. 4. You Still Need a Down Payment Porting doesn’t mean you “swap houses” without cash. You still need: A down payment on the new purchase Closing costs Funds available at the right time This often surprises buyers. 5. Penalties Usually Still Apply (At First) Most lenders: Charge the full mortgage penalty when you sell Refund it only after the port is successfully completed If you’re relying on sale proceeds for your down payment, this temporary penalty can create a cash-flow issue. 6. Timelines Rarely Line Up Perfectly Real estate markets don’t cooperate. You might: Sell quickly but struggle to buy Find a home quickly but wait months to sell Closing dates rarely align, which complicates porting even further. 7. Port Periods Vary by Lender This is where the fine print matters. Depending on the lender, the port window may be: Same day only 30 days 90 days Up to 6 months If the port window is short, both transactions must close within that timeframe—or the port fails. Longer port periods offer flexibility, but also carry the risk of selling first and not finding a replacement property in time. The Bottom Line Porting your mortgage can make sense—especially if you have a strong rate and are buying a similar-priced home. But it is not guaranteed , and it comes with conditions, risks, and timing challenges. Portability is a feature, not a promise. Before you rely on it, it’s important to review all your options , including whether staying with your lender actually makes financial sense. If you’re planning to sell and buy, I’d be happy to walk you through the process, explain your options clearly, and help you decide whether porting is the right move—or if another strategy makes more sense.