Should you underpin or bench-foot a low basement in an older Markham home?Underpinning extends the foundation walls deeper so the whole basement floor can be lowered. Bench footing lowers the middle of the floor and leaves a concrete ledge along the walls, which uses some floor area but is usually simpler. Both need an engineer and a building permit. Under the 2024 Ontario Building Code, a secondary suite can have a 1.95 m ceiling and 1.85 m under beams and ducts.
Many older homes in Markham Village, Unionville and Thornhill sit on large lots but have low basements that limit how the space can be used.
Michael John Lau, a REALTOR® with the Kaizen Real Estate Team, one of the most active real estate teams in Markham and York Region, helps buyers judge basement potential before they offer.
The two methods
| Method | How it works | Trade-off |
|---|---|---|
| Underpinning | Foundation dug deeper in sections | Full floor area; more complex |
| Bench footing | Centre floor lowered, ledge left at walls | Loses some floor area; usually simpler |
Height rules
For a secondary suite, the 2024 Ontario Building Code allows a 1.95 m ceiling height, with at least 1.85 m clear under beams and ducts. These reduced heights apply to secondary suites, so confirm the rules for any other use with the City.
Permits and engineering
- A structural engineer designs the work.
- A building permit is required before digging.
- Drainage, waterproofing and plumbing often change.
- Neighbours may need notice for shared or close walls.
Looking at a home with a low basement?
Michael John Lau can help you weigh basement potential in your offer.
Book a buyer consultationSearch Markham homesPrefer to talk? Call the Kaizen Real Estate Team at (647) 370-8885.
Before you buy
- Measure the current ceiling and under beams and ducts.
- Ask about past water and the foundation’s condition.
- Get a contractor’s opinion during your conditional period.
Is it worth it?
Lowering a basement can add usable space and suite potential, but costs vary widely by house and soil. Compare the cost with the value of the extra space. Ultimately, the decision is yours. The goal is to make sure you have all the information before you start.
Headroom is easier to plan for before you buy than after. Call the Kaizen Real Estate Team at (647) 370-8885 or book a consultation.
Frequently asked questions
What is underpinning?
Deepening the foundation walls so the basement floor can be lowered.
What is bench footing?
Lowering the centre of the floor and leaving a ledge along the walls.
What ceiling height does a basement suite need in Ontario?
1.95 m, with 1.85 m under beams and ducts, under the 2024 Ontario Building Code.
Do I need a permit to underpin in Markham?
Yes. Structural work needs a building permit and an engineer.
Which method costs less?
Bench footing is usually simpler, but quotes vary by home.
Can I underpin in winter?
Often yes, but ask your contractor about timing and drainage.
Michael John Lau and Neeraj Moolchandani are licensed REALTORS® with the Kaizen Real Estate Team, eXp Realty, Brokerage, 9763 Markham Rd, Markham, ON L6E 1A4. Licence #4784577. Call (647) 370-8885. Ceiling heights are from the 2024 Ontario Building Code, Sentences 9.5.3.1.(2) and (3), as summarized by OBOA. Confirm permit requirements with the City of Markham Building Standards. This article is general information only and is not financial, legal or tax advice. Not intended to solicit buyers or sellers currently under contract with another brokerage.
