Building Your Own Home in Ontario: How Construction Mortgages Work

A construction mortgage is a home loan that pays out in stages while your house is being built, instead of all at once on closing day. The lender releases the money as each part of the build is finished and checked, and you usually pay interest only on the money released so far.

If you're planning to build in Ontario, whether that's a new home on your own lot or a tear-down and rebuild, the financing works very differently from buying a finished home. This guide explains how it works, step by step, in plain English.

Quick answer: A construction mortgage in Ontario pays for your build in stages, called draws. Before each draw, the lender usually has the work checked. While you build, you typically pay interest only on the money released so far, and when the home is finished the loan is replaced by, or turns into, a regular mortgage. Whether you're approved depends on your income, credit, down payment, land, plans, builder, and each lender's own rules.

Below you'll find a worked example of how draws work, what changes if you hire a builder or manage the build yourself, the step-by-step path from idea to move-in, the costs people forget, and five mistakes to avoid.

Key Takeaways

• A construction mortgage pays out in stages, called draws. The lender usually has the work checked before it releases each one.
• While your home is being built, you typically pay interest only on the money released so far, not on the whole loan.
• CMHC's insured program for building a home works through progress advances, and it doesn't allow loan advances on vacant land, so you'll generally need to own the lot first.
• Under Ontario's Construction Act, 10% of the price of construction work must be held back until the time for tradespeople to make claims has passed. Ask your lawyer how that fits with your draws.
• A builder who builds a home for you on your land needs an HCRA licence. A home you build yourself usually has no Tarion new home warranty.
• Plan a cushion for surprise costs. As an example only, 10% of a $500,000 build is $50,000. A licensed mortgage broker can compare lenders before you buy land or sign a building contract.

What Is a Construction Mortgage?

A construction mortgage works by paying for your home in stages as it goes up, instead of handing you the whole loan on day one.

A regular mortgage buys a home that already exists. A construction mortgage pays for a home that doesn't exist yet, so the lender has nothing finished to point to. That's why lenders check the work as it goes.

Definition moment: A draw (the word lenders use for each payment of your construction loan) is money released after a set stage of the build is finished and checked. CMHC calls the same thing a progress advance.

CMHC, Canada's national housing agency, offers mortgage insurance for people building a home, called CMHC Improvement. According to CMHC, its full-service option has CMHC check up to 4 advances in a row, and with the basic service your lender does the checking instead.

Ontario adds its own layer on top: municipal building permits, a rule that holds back 10% of what's paid for construction work, and warranty rules from Tarion. We'll cover each one below.

Bottom line: A construction mortgage isn't harder because lenders are being difficult. It's different because they're funding something that isn't finished yet. Knowing the stages in advance is the best way to keep your build on schedule.

How the Money Is Paid Out: A Draw-by-Draw Example

Draws work by tying each payment to a finished stage of the build, so the lender only pays for work that's already done.

Example only: The numbers below are made up to show the idea. Every lender and builder sets its own schedule, and the number of draws and the amounts will be different for your build.

Here's how interest works in the same example. After draw 1 you owe interest on $100,000, not $500,000; after draw 2 on $250,000; after draw 3 on $400,000; and after draw 4 on the full $500,000. That's why payments start small and grow as the build moves along.

Before each draw, the lender usually sends an inspector or appraiser to confirm the work is done. That check takes time, so ask your lender how long it usually takes.

What Ontario homeowners often miss: Your builder's bills and your lender's draws don't always line up perfectly. If a draw arrives after an invoice is due, you may need to cover a short gap yourself. Ask both sides how they'll handle it before you sign.

Definition moment: Holdback (a slice of each payment to a builder that's kept back for a set time) is required by Ontario's Construction Act. Under the Act, 10% of the price of the work is held back until the time for claims from unpaid tradespeople, called liens (legal claims on your property), has passed. The rules on when holdback is released changed in January 2026, so ask your lawyer for the current timing and how it fits with your draws.

Hiring a Builder or Managing the Build Yourself

The difference between hiring a licensed builder and managing the build yourself is who carries the risk, and lenders look at that closely.

Definition moment: An owner-builder (someone who builds their own home to live in and acts as their own project manager) takes on the jobs a builder would normally handle: hiring trades, ordering materials, and keeping to the budget.

According to HCRA (Ontario's Home Construction Regulatory Authority), a builder who builds a home for you on your own land needs a licence, and the home has to be enrolled with Tarion, Ontario's new home warranty provider. Ask for the builder's HCRA licence number and check that the legal name matches your contract.

Not every lender offers construction financing, and some won't lend to owner-builders at all. That's one reason to talk to a licensed mortgage broker before you spend money on plans and permits, and our guide to banks versus mortgage brokers in Canada explains the difference.

Bottom line: If you're hiring a builder, check their HCRA licence and warranty enrolment before you sign anything. If you're building it yourself, expect more questions from lenders and take extra care with your budget.

Step by Step: From Idea to Move-In

Getting a construction mortgage works best in a set order, because each step decides what's possible in the next one.

1. Talk to a mortgage broker first. Do it before you buy land or sign a building contract, because your budget and your lender options shape both.
2. Line up the land. CMHC's insured program doesn't allow loan advances on vacant land, so many lenders expect you to own the lot first, or to buy it separately.
3. Get your plans, permit and price. You'll need building plans, a municipal building permit, and a written quote or fixed-price contract from your builder.
4. Apply with your documents. The list is just below. Complete files move faster.
5. The lender reviews the project. They look at your plans, your budget, and a professional's estimate of what the finished home will be worth. Then they set your draw schedule.
6. Build and draw as you go. Each stage is checked before the next payment is released. Keep every receipt and invoice.
7. Finish and move to a regular mortgage. Ask early whether your lender turns the construction loan into a regular mortgage automatically, or whether you'll need to arrange a new one at the end.

Documents lenders often ask for

• Building plans and your municipal building permit
• A detailed budget or a fixed-price contract from your builder
• Proof of who owns the land, or the purchase agreement for it
• Proof of income, credit history, and where your down payment is coming from
• Proof of insurance that covers the home while it's being built
• If you're building it yourself: your building experience, a schedule, and a list of the trades you'll hire

Wondering where your down payment can come from? Read our guide to down payment rules in Canada. If your down payment is under 20%, here's how CMHC mortgage insurance works.

What Building Costs Besides the Build

Building a home in Ontario costs more than your builder's price, because land, taxes, fees, interest and insurance all add to the total.

• Land and land transfer tax. Buying a lot means paying Ontario land transfer tax on the price of the land, and Toronto adds its own tax on top for property inside the city.
• Permits and connection fees. Your city sets fees for building permits, and there may be charges for connecting water, sewer and power.
• Interest during the build. You'll typically pay interest each month on the money released so far, until the home is finished.
• Insurance while it's being built. Lenders usually require insurance that covers the home during construction.
• Taxes on new homes. The CRA has a GST/HST rebate application for owner-built homes, called Form GST191. Whether you qualify depends on the details, and there's a deadline, generally within 2 years of when the home is substantially finished.
• Legal and closing costs. Expect lawyer's fees and other costs when the project wraps up.
• A cushion for surprises. As an example only, a 10% cushion on a $500,000 build is $50,000.

To estimate the tax on your lot, read how Ontario land transfer tax works or try our land transfer tax calculator. For the rest of the bills at the end, see our guide to closing costs in Ontario.

What Ontario homeowners often miss: A builder's price may not include everything. Driveways, landscaping, appliances and window coverings can all be extras. Ask your builder for a written list of what's included and what isn't.

Bottom line: Build the extra costs and a cushion into your budget from day one. It's much easier to plan for them now than to find the money halfway through the build.

Building in Ontario: What to Check Locally

Building in Ontario means your city, your conservation authority and your lender all have a say, so local checks matter as much as the mortgage.

Whether you're rebuilding on an older lot in Scarborough or North York, adding a new home on a larger lot in Pickering, Ajax or Richmond Hill, or building on rural land near Ottawa, the steps are similar but the local rules aren't. Check with your city early.

If you're replacing an existing house, tell your broker up front. The mortgage on the old home usually has to be dealt with before, or as part of, the new financing.

Building near a river, ravine or wetland? Your local conservation authority (the regional body that protects rivers and wetlands) may need to approve the plans on top of the city's building permit. On rural land, ask early about water and septic (a private well and sewage system) approvals.

Bottom line: Your mortgage plan and your local approvals depend on each other. Check both before you set a budget or buy land, and review your options with a licensed mortgage professional first.

5 Mistakes to Avoid When Financing a New Build

These mistakes cost people time and money on a build, and every one of them can be avoided by checking the details first.

1. Buying the land before checking your financing. Some lenders have rules about the land, and CMHC's insured program doesn't allow advances on vacant land. Talk to a broker before you sign for a lot.
2. Skipping the cushion. Building costs can rise mid-build. Set money aside, for example $50,000 on a $500,000 build as an example only, so a surprise doesn't stop the project.
3. Not checking your builder. Ask for the HCRA licence number, confirm the name matches your contract, and ask whether your home will be enrolled in Tarion's warranty.
4. Forgetting how the loan ends. Ask whether your construction loan turns into a regular mortgage automatically. If not, you'll qualify again when the home is finished, with whatever your income and credit look like then.
5. Ignoring holdback and paperwork. Ontario's Construction Act requires 10% to be held back from payments for the work. Keep every invoice, and ask your lawyer how your draws and the holdback fit together.

Useful Resources for Ontario Homebuyers

If you already own a home, its equity (the part you've paid off) may help fund part of a build. See how refinancing in Ontario works.

Talk to a licensed Ontario mortgage broker before you commit to land or a builder.

Frequently Asked Questions: Construction Mortgages in Ontario

How does a construction mortgage work in Canada?

A construction mortgage pays for your build in stages, called draws, instead of one lump sum. After each stage is finished, such as the foundation and then the frame and roof, the lender usually has the work checked and then releases the next payment. During the build you typically pay interest only on the money released so far. When the home is finished, the loan is replaced by, or turns into, a regular mortgage. Every lender sets its own rules, so ask for the draw schedule in writing before you commit.

Do I need to own the land before I get a construction mortgage?

Often, yes. CMHC says its insured program for building a home does not allow loan advances on vacant land, so many lenders expect you to own the lot first. Some lenders have their own rules and may handle land differently, so check before you sign a land purchase agreement. If you're buying the lot as well, tell your mortgage broker early, because how the land is bought can change which lenders fit your plan and how much money you need up front.

How much down payment do I need to build a house in Ontario?

It depends on the lender and your plan. CMHC's insured program allows lending up to 95% of the finished home's value on a home with one or two units that you'll live in, which means a down payment smaller than 20% may be possible. Lenders can set stricter rules, though, and often ask for more if you're managing the build yourself. A licensed mortgage broker can check your situation against different lenders' rules before you decide how much to save.

What happens to my construction mortgage when the house is finished?

When the build is done and the final inspection is passed, the construction loan is replaced by, or turns into, a regular mortgage with a set term. Some lenders convert it automatically. Others need you to arrange a new mortgage, which means qualifying again based on your income and credit at that time. Ask which one applies before you sign, because it affects your risk at the end of the build.

What should I do if a bank turns down my building plan?

Ask why, in plain terms. The issue might be the land, the plans, the builder, the budget, or your own income and credit, and each one has a different fix. Some lenders are more comfortable with owner-built or unusual projects than others, so one decline isn't the end. A licensed mortgage broker can compare options for your situation, including using equity in a home you already own. Approval depends on income, credit, down payment, land, plans and each lender's rules.

Should I use a mortgage broker for construction financing?

It's worth speaking with one early, before you buy land or sign a building contract. Not every lender offers construction financing, and their rules differ on land, builders and owner-built homes. A licensed mortgage broker can explain which paths may fit your plan and what documents lenders usually want to see. lendsimpl is a licensed mortgage brokerage in Ontario (FSRA #13763), and reviewing your options is a low-pressure first step.

Disclaimer

This article is for general educational purposes only and should not be taken as financial, legal, or mortgage advice. Mortgage options, rates, approvals, and lender requirements can vary based on borrower profile, property details, credit history, income, equity, documentation, and current market conditions. Speak with a licensed mortgage professional before making a mortgage decision. lendsimpl is a licensed mortgage brokerage in Ontario (FSRA #13763).