- A basement walkout is a door from the basement straight to the yard. On a sloped lot it opens at grade; on a flat lot it's a walk-up with stairs and retaining walls.
- Typical Hamilton-area costs are $15,000 to $30,000 for a walk-up entrance and $25,000 to $50,000 for a full walkout with retaining walls.
- Cutting a new opening in a foundation wall is structural work, so it needs a building permit, and the opening is usually designed from engineered drawings.
- The drain at the bottom of the stairs is what keeps a walkout from leaking, and in Halton, disconnecting a walkout drain from the sewer can be fully subsidized.
What a basement walkout is
A basement walkout is an exterior door at basement level that opens straight to the yard. It turns a basement from a space you go down into into one you can walk out of, with daylight, fresh air and its own entrance.
People add them for a few reasons:
- A separate entrance for a basement apartment or in-law suite.
- Direct backyard access from a family room or rec room.
- More daylight, and a second way out of the basement.
- Making use of a sloped lot where part of the basement wall is already exposed.
Walkout or walk-up: what your lot allows
The slope of your lot decides what's possible.
- Full walkout. The ground falls away from the house, so the basement wall is partly above grade on that side. We cut an opening in the wall and you step out at, or close to, yard level.
- Walk-up entrance. On a flat or gently sloped lot, we excavate a stairwell down to basement level, build retaining walls and stairs, and put the door at the bottom. You walk up to the yard.
Sloped lots near the escarpment, in places like Ancaster, Burlington, Stoney Creek and Waterdown, can be natural walkout candidates. Flat lots almost always mean a walk-up. We'll tell you which one your grade supports at the first visit.
How a basement walkout is built
- 01
Assess the grade and the wall
We look at the slope, the soil, where the opening can go, and what's in the wall now: windows, beams, plumbing or wiring.
- 02
Drawings and permit
An engineer designs the opening, the lintel above it and any retaining walls. The drawings go in with the permit application.
- 03
Excavate and retain
We dig out the stairwell or the area in front of the opening, then build the retaining walls and stairs on proper footings.
- 04
Cut the opening
The wall is supported, the new opening is cut, and a properly sized lintel goes in to carry the load above it.
- 05
Drain, waterproof and finish
A drain at the bottom that carries rain to a storm sewer, a dry well or a ditch (or to a sump that discharges to one), waterproofing on the new walls, then the door, the landing and the outside finishes.
Frost matters as much outside as in. The Building Code's minimum footing depth for a house in clay soils is 1.2 m, to keep frost from lifting it, and the new walls are designed with that in mind.
Permits and drawings for a basement walkout
Ontario's Building Code Act requires a permit before any material alteration of a building, and a new opening in a foundation wall is exactly that. Municipalities around Hamilton name it directly:
- Oakville and Mississauga list a below-grade entrance or basement walkout as work that needs a permit.
- Milton requires a permit for new exterior openings, including below-grade entrances, with a site plan, a floor plan and a wall section showing drainage and flashing.
- Burlington's building permit by-law lists basement walkouts and exterior stairs.
- Haldimand County (Caledonia) lists creating or enlarging a below-grade entrance, and Brantford lists new above- and below-grade entrances.
- In Hamilton, including Ancaster, Dundas, Stoney Creek and Waterdown, permits come from the City's Building Division, and its permit checklist asks whether conservation authority or Niagara Escarpment Commission approval applies.
Stamped drawings typically run $1,500 to $5,000. We coordinate them and the permit, and check early whether your lot needs a conservation authority's approval, because that can add time before we start.
The drain at the bottom is the whole job
Every walk-up collects rain and snowmelt at the bottom of the stairs. If that water has nowhere to go, it ends up against the door, and the new entrance becomes the new leak. A properly built walkout has a drain at the bottom of the stairwell, a landing sloped toward it, and waterproofing on the new walls.
Where that drain goes matters too. Hamilton's sewer use by-law prohibits sending stormwater into the sanitary sewer. Under the 2024 Building Code, a stairwell drain carries storm water, so it has to go to a storm drainage system, a dry well or a ditch, not into the weeping tile. Where gravity won't do it, a sump that discharges to one of those is the answer.
Already have a walkout whose drain is tied into the sewer? For homes in Burlington, Oakville and Milton, Halton Region pays 100% of disconnecting it, up to $6,500, and a new sump or outlet needs a permit. Our basement flooding subsidies guide has the details.
Walkouts, bedrooms and basement apartments
A walkout is often the entrance to a basement unit, and it changes the egress picture. Ontario's Building Code requires every floor level with a bedroom to have an outside window that opens to at least 0.35 m², with no dimension under 380 mm, unless there's a door on the same level that leads directly outside. A walkout door can be that door.
A secondary suite has more rules on top of that, including a minimum ceiling height of 1.95 m under the 2024 Code. If a suite is the goal, plan the walkout and the suite together, so the door, the floor height and the layout all line up.
What a basement walkout costs
Every walkout is different. These are the things that move the price:
- How deep the excavation goes and how long the retaining walls are.
- The size of the opening and the lintel it needs.
- Soil, groundwater and access for equipment.
- The door, stairs, railings and landing finishes.
- Moving anything in the way: windows, ducts, plumbing or wiring.
| Scope | Typical range |
|---|---|
| Walk-up entrance with stairs, drain and door | $15,000 to $30,000 |
| Full walkout with retaining walls on a sloped lot | $25,000 to $50,000 |
| Engineered drawings | $1,500 to $5,000 |
Typical Hamilton-area market ranges before tax, drawn from 2026 Ontario price guides and published contractor rates. Your quote is written and fixed after we've seen the grade.
A walkout often pairs with lowering the basement. If you're doing both, plan them together so the floor and the door line up. See our guide to lowering a basement floor.
Not sure you need a full walkout?
If the goal is daylight or a legal bedroom rather than a door, a bigger egress window with a proper window well may do the job for less. The Building Code asks for an opening of at least 0.35 m² with no dimension under 380 mm, at least 550 mm of clear space in front of the window inside the well, and a well that drains to the footing. Any cover over the well has to open from inside without keys or tools.
Enlarging a window opening in a foundation wall is still structural work, and municipalities like Cambridge list enlarged window or door openings as permit work, so it's designed and permitted the same careful way, just smaller. Our sister company Basement Worx handles window wells and drains, and we'll tell you honestly whether a window or a walkout fits what you're after.
How long a walkout takes
Most walkouts take a few weeks on site, from excavation to finished door, once the permit is issued. It's outdoor excavation work, so weather plays a part, and conservation authority approval on some lots can add time before we start. You'll get a schedule with your quote.
Basement walkout questions
How much does a basement walkout cost?
Do I need a permit for a basement walkout?
Can you add a walkout to a flat lot?
Will a walkout make my basement leak?
Do I need an engineer for a walkout?
Walkouts and related work
Related guides
AVH Foundations works across Hamilton, Burlington, Oakville, Milton, Ancaster, Dundas, Stoney Creek, Waterdown, Cambridge, Brantford, Caledonia and Grimsby.