A-509 Additions & New Builds
Underpinning and basement lowering, engineered in-house
Underpinning extends a house’s foundation deeper so the basement floor can be lowered for more ceiling height. In Toronto it needs a permit and an engineer, and typically costs $25,000 to $150,000.
- Typical cost
- $25,000–
$150,000 - Timeline
- 4–12 weeks on site
- Permit
- Yes, permit and engineer
- Prices checked
- 2026
- In-house engineering and permits
- Free on-site estimate
- MKC Guarantee: on time, within budget
Free, no-obligation estimate. We typically reply within 24 hours.
A-509.1 Why MKC
Why choose MKC for underpinning
Many older Toronto basements are too low to finish or rent out. Lowering one means digging below the footings that hold up the house, so the work is done in short sections, in a set order, to an engineer’s drawings. Our engineering department designs the underpinning, prepares the permit drawings and reviews the work on site, and our crews build it. Before quoting, we look at the soil, the drains and how close the neighbouring foundation is.
Underpinning or bench footing
Underpinning places new concrete under the existing footings, so you keep the full floor area. Bench footing leaves the footings alone and pours a concrete ledge inside the walls. It costs less and avoids digging under the footings, but the ledge takes floor space around the room.
A-509.2 Scope
What’s included
- A-509.1Site and soil reviewFooting depth, soil, water table, drains and the neighbouring foundation, checked before design.
- A-509.2Engineering and permitStamped drawings showing the stages and depth, and the building permit application, in-house.
- A-509.3Sectional underpinningThe foundation is dug out and poured in short sections, in the sequence the engineer sets.
- A-509.4Bench footingA reinforced concrete bench inside the walls, where digging under the footings is not practical.
- A-509.5New slab and drainsUnder-slab drains, gravel and a new concrete floor, with drain work by a City-licensed contractor.
- A-509.6Waterproofing and entrancesMembrane on exposed walls, a sump pit or backwater valve, and a basement walkout if you want one.
A-509.3 Cost guide
What it costs
in Toronto & the GTA
Underpinning a Toronto basement typically costs $25,000 to $150,000. The low end is structural work only; the high end adds the new slab, drains and rough-ins.
Structural-only underpinning up to a full-perimeter package with slab and drains
Engineering and the permit take about 8 to 12 weeks before digging starts; underpinning on a house with up to two units qualifies for Toronto’s Express Services, which aims to review applications within 3 business days. The structural phase takes about 4 to 8 weeks on site, or 8 to 12 weeks when the new slab, drains and rough-ins are included.
Every project is different, so your estimate comes with its own written schedule, and we aim to beat the usual industry timeline on every job.
| Level of work | Typical cost |
|---|---|
| Structural underpinning, houseSectional underpinning of the perimeter at $200 to $300 per linear foot. Structure only, no finishing. | $25,000– |
| Bench footingConcrete bench inside the existing walls and a lowered slab, with drawings and permit. Loses floor area. | $30,000– |
| Older or deeper underpinningOlder houses or about 3 ft of added depth, at $300 to $450 per linear foot. Structure only. | $35,000– |
| Full-perimeter packageUnderpinning with engineering, permit, soil report, new slab and basic rough-ins. | $80,000– |
| Item | Typical price |
|---|---|
| Underpinning, 1 to 3 ft of added depth | $200– |
| Waterproofing while the wall is exposed | $80– |
| Engineer design and stamped drawings | $4,500– |
| Geotechnical soil report | $1,800– |
Worked examples
- Example 1
25 ft × 40 ft Toronto basement lowered 1 to 2 ft: structure, engineer and permit
$31,000–$47,000 - Example 2
The same basement with waterproofing added while the walls are exposed
$41,500–$62,500 - Example 3
Row house, about 110 ft of foundation, lowered 2 ft, structure only
$38,000–$41,500
What moves the number
- 01Depth gained
Per linear foot of wall, structural underpinning runs about $200 for one foot of added depth, $300 for two feet and $450 for three.
- 02Scope beyond structure
Structural work alone on a detached house runs $25,000 to $45,000. With a new slab, drains and rough-ins, a full-perimeter job reaches $80,000 to $150,000.
- 03Soil and water
Wet clay or a high water table adds about 25%, and so does sandy or unstable soil. A geotechnical soil report costs $1,800 to $3,500 or more.
- 04Shared and close walls
Semi-detached houses add about 10% to 15%, and row houses and narrow lots 15% to 25%. Digging below a neighbour’s footing level needs an engineer.
- 05Method
Bench footing on a typical detached house runs $30,000 to $60,000 with drawings and permit, but it gives up floor area along the walls.
Rebates, subsidies and tax credits
- Up to $6,650 per propertyCity of Toronto Basement Flooding Protection Subsidy Program
Does not cover underpinning. May pay up to 80% of the invoiced cost of backwater valves (up to $1,600 each, two at most), a sump pump (up to $2,250), a battery backup (up to $300), weeping tile capping (up to $400) and a plumbing assessment (up to $500). Denied unless the installer holds the right City licence. Apply within two years.
Program rules
Low confidence: two published GTA sources that price different scopes. Before HST. Structural ranges leave out the new slab, drains and finishing. Prices checked in 2026. Not a quote: your estimate is built from your own measurements and choices.
Where these numbers come from
- Residential Underpinning (including basement entrances) permit guide, City of Toronto (2026)
- Building Permit Fees, City of Toronto (fees effective January 1, 2026)
- Building Permit Review Streams, City of Toronto (2026)
- Basement Flooding Protection Subsidy Program, City of Toronto (2026)
- Published 2026 price guides and GTA contractor price pages (2026)
G-003 How we work
How we deliver your underpinning project
- 1
Free Estimate
Tell us what you have in mind. We review your space and goals and give you a clear estimate at no cost.
- 2
Design + Permits
Our in-house designers model your project in 3D so you can see it and settle every choice. Our in-house engineering team prepares drawings, engineering letters and permit applications.
- 3
Material Procurement
We order cabinets, tile, stone, pavers and decking from trusted suppliers such as Unilock, Techo-Bloc, TimberTech and Trex, and schedule deliveries around the work.
- 4
Construction Process
Our crews build to code with site supervision and regular updates, so you always know where things stand.
- 5
Project Completion
Final inspection, walkthrough and clean-up. On time, within budget and beyond expectations. That is the MKC Guarantee.
Plan your project
with a free estimate.
We review your space and goals and give you a clear estimate at no cost.
A-509.4 Questions
Questions about underpinning
Don’t see your question? Call (647) 637-6052 or ask in your estimate request.
How much does underpinning cost in Toronto?
Typical cost in Toronto and the GTA: $25,000 to $150,000 (Structural-only underpinning up to a full-perimeter package with slab and drains). By level of work: Structural underpinning, house: $25,000 to $45,000; Bench footing: $30,000 to $60,000; Older or deeper underpinning: $35,000 to $65,000; Full-perimeter package: $80,000 to $150,000. Scope moves the price most: structural work alone costs far less than a full package with a new slab, drains and rough-ins. Depth gained, soil and shared walls come next. These are typical ranges, before HST, with prices checked in 2026; your estimate is built from your own measurements and choices.
Do I need a permit to lower my basement?
Yes. The City of Toronto requires a building permit to underpin the foundation of an existing house, and the drawings must show the stages and the depth of the underpinning. The 2026 fee is $12.37 per linear metre of underpinning, with a minimum of $214.79. On a 25 ft by 40 ft house that comes to about $490. We prepare the drawings and file the application.
When is an engineer required?
Toronto requires a Professional Engineer to design the work and review it on site when you dig below the footing level of an adjacent building, when the underpinning is more than 1,200 mm high without lateral support, or when the soil is clay or silt. For all underpinning, the engineer provides reports at the first and last stages. Our in-house engineers do the design and the site reviews.
Underpinning or bench footing: which suits my house?
Underpinning keeps the whole floor area, which matters in a basement you plan to finish or rent. Bench footing costs less and does not dig under the footings, but it leaves a concrete ledge around the room. We measure the basement, look at the neighbouring foundations and price both options side by side.
How much height can I gain?
Published Toronto prices cover one to three feet of added depth, and each extra foot costs more per linear foot. The limit for your house depends on the soil, the water table, the neighbouring foundations and the depth of the sewer connection, since the drains still have to flow out. Our engineers confirm the depth before design.
Should I waterproof while the walls are exposed?
It is worth pricing. Waterproofing added while the wall is open runs about $80 to $120 per linear foot. On a house with 130 feet of foundation, that is $10,400 to $15,600 on top of the underpinning. Ask us to show it as a separate line in the estimate.
Can I add a backwater valve or sump pump at the same time?
Yes, and the floor is already open. Toronto’s Basement Flooding Protection Subsidy does not cover underpinning, but it may pay up to 80% of the invoiced cost, to a maximum of $1,600 per backwater valve (two at most), $2,250 for a sump pump and $300 for a battery backup. The City denies the subsidy unless the installer holds the right City licence, so that work is done by a City-licensed drain or plumbing contractor.
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