Guide · Updated September 10, 2026
Separate Entrance or Walkout? Which One Your Basement Needs, and What It Takes to Build
People use the two words interchangeably. They are different structures, they suit different lots, and they go through different approvals. This guide is the conversation we have on every first visit, written down — with the municipal rules it rests on linked to their sources.
The difference
A separate entrance is a below-grade stairwell cut into the ground beside or behind the house, leading down to a new exterior door in the foundation wall. The stairwell has concrete walls and a footing, a drain at the bottom, and a guard or railing at the top. It works on a flat lot, which is most lots.
A walkout is an at-grade door: the ground outside is already at basement-floor level, so you walk straight out onto a patio or the yard. It needs the lot to fall roughly a full storey from front to back, or a rear yard that can be regraded to get there. Walkouts are common in subdivisions built on sloping ground and rare everywhere else.
Municipal fee schedules tend to treat them as one permit class — Milton lists "basement walkout or exterior stairs" as a single item, and Halton Hills prices "walkouts, exterior stairs and ramps" together — but the construction, and what your lot allows, are different questions.
Which one your lot can have
Grade decides it. If the rear yard sits close to the level of the basement slab, a walkout is possible and is the better result: more light, a real door to the yard, and a patio instead of a stairwell. If the yard is roughly level with the main floor — the ordinary case — the only route is a stairwell, and the question becomes which wall it goes on.
Side yard width is the second test. A stairwell needs room for its own walls plus a walkway past it, and several municipalities set the walkway width in the zoning by-law. Milton requires an unobstructed pedestrian route at least 1.2 metres wide and 2.1 metres high from the street line to the entrance that gives the most direct access to the unit, with utility meters allowed inside that width and window wells allowed to project no more than 0.3 metres into it. Where the side yard is tight, the gas meter and the air-conditioning condenser are what usually make or break it, and both can be relocated.
Which wall is allowed is the third. The former Flamborough by-law that still governs Waterdown allows only one entrance on the front facade of a house with a second unit, and Hamilton's 2022 amendments carried the same rule; the City's current urban consolidation should be checked for your zone, and in practice the new door goes on the side or the rear. Other municipalities are silent on placement and let the path rule decide. The rule for your address is on your city's page — see the service areas index.
The approvals
A building permit, always. Cutting an opening in a foundation wall and building a stairwell or a walkout is structural work and needs a permit in every Ontario municipality. The drawings show the opening, the lintel over it, the stairwell walls and footing, the drain, the guard, and a section from grade to the underside of the footing. Where the entrance serves a new second unit, it is usually applied for together with the suite permit.
The conservation authority, if the lot is regulated. Conservation authorities define development to include placing a structure and placing or removing material, so a stairwell excavation on a regulated lot needs their permission before the building permit can issue. Conservation Halton, for example, regulates an allowance of 15 metres beyond the flood plain, stable top of bank or meander belt of a watercourse and 30 metres from a wetland; their online mapping shows whether a property is inside, and the authority asks you to confirm with staff because the mapping is approximate.
Heritage, the Escarpment and private services, where they apply. A designated heritage property needs a heritage permit for an exterior change such as a new stairwell. Inside the Niagara Escarpment Commission's development control area, a Development Permit comes before the municipal permit, and the Commission treats creating a secondary dwelling unit as a change of use that is never exempt. On a septic lot, the stairwell cannot cross the leaching bed, and adding a unit triggers a septic evaluation. Each of these is checked on the first visit; none of them is discovered halfway through.
What the work involves
For a separate entrance, the site work runs in a fixed order: locate services and mark the stairwell; excavate down to just below the basement slab; shore as needed; form and pour the stairwell walls and footing; cut the opening in the foundation wall and install the lintel; set the door frame, door and sill; tie the stairwell drain into the weeping tile or a sump; waterproof the new walls and the cut; backfill and re-grade so surface water runs away from the stairwell; and install the guard and any lighting. HMH builds the entrance itself in three days once the permits are in hand. Interior finishing of the landing and the connection to the suite follows under the suite permit.
A walkout is a different job: regrading the rear yard, often a retaining wall on one or both sides, a larger opening for a door or a door-and-window combination, a landing or patio at grade, and drainage so the patio does not sheet water into the house. It is typically more excavation and more concrete than a stairwell, and it changes how the yard is used.
What drives the cost
We do not publish prices, because the same drawing can cost very different amounts on two lots. These are the variables that move the number, in the order they usually matter:
Depth and soil. How far below grade the slab sits sets the excavation and the height of the stairwell walls; clay, sand and rock dig and hold differently, and high water tables change the drainage design. Access. Whether an excavator can reach the side yard or the work has to be done by hand. The foundation. Poured concrete, concrete block and stone rubble each cut and reinforce differently, and a rubble foundation may need more structural work around the opening. Drainage. The distance from the stairwell to a drain connection or a sump. What is in the way. A gas meter, a condenser, a hydro service, a downspout or a window well on the chosen wall. Approvals. A conservation permit, a heritage permit or an NEC Development Permit each add a step, and the conservation authority may require the stairwell be moved or protected. What it connects to. An entrance to a storage basement is one scope; an entrance that is the exit for a new legal unit brings the suite's fire separation, alarms and finishing with it.
The mistakes we see
A stairwell with no drain, which fills in the first storm. An entrance on the front of the house in a municipality that does not allow it there, which fails at permit. A stairwell built in the side yard that leaves less than the required path width, which the inspector measures. Excavation on a regulated lot without asking the conservation authority, which stops the job. And a beautifully built entrance to a basement that never had the headroom to be a legal unit — which is why we measure the ceiling before we talk about the door.
Questions This Guide Answers
Do I need a permit for a separate basement entrance?
Yes, in every Ontario municipality. It is a structural alteration to the foundation and a new exterior stair, and it needs a building permit with drawings showing the opening, the lintel, the stairwell walls and footing, the drain and the guard. Municipal fee schedules list it as its own permit class. If the entrance serves a new second unit, the two permits are usually applied for together.
Which is cheaper, a separate entrance or a walkout?
On a flat lot only a stairwell is possible, so the comparison does not arise. Where a lot can take either, a walkout usually involves more excavation, regrading, retaining walls and a patio, so it is generally the larger job — but it also delivers more: light, a real door to the yard, and a basement that feels like a ground floor. We price both where both are feasible and let you choose.
Can I put the new entrance on the front of my house?
It depends on the municipality. The former Flamborough by-law that still governs Waterdown allows only one entrance on the front facade of a house with a second unit, and Hamilton's 2022 amendments carried the same rule, so in those places plan on the side or the rear and have the current zoning text checked for your lot. Other municipalities have no placement rule and rely on the pedestrian-path requirement. Check your city's page, or ask us to check the zoning for your address.
How wide does my side yard need to be?
Wide enough for the stairwell and a walkway past it that meets your municipality's rule. Milton, for example, requires an unobstructed pedestrian route at least 1.2 metres wide and 2.1 metres high from the street line to the unit's entrance, with utility meters permitted within that width and window wells allowed to project up to 0.3 metres into it. Where the yard is close to the limit, relocating the gas meter or the air-conditioning condenser is often what makes it work.
How long does it take to build a separate entrance?
The site work — excavation, stairwell, opening, door, drain, waterproofing and backfill — is built in three days once the permit is issued and the ground is workable. The permit itself depends on the municipality and on whether a conservation authority or heritage approval comes first; those are measured in weeks. Interior finishing of the landing and any suite work follows under its own schedule.
Will the stairwell flood?
Not if it is built with a drain at the bottom tied into the weeping tile or a sump, the new walls and the cut waterproofed, and the surrounding grade sloped away from the opening. A stairwell that floods is almost always one built without the drain or with the grade running toward it. On a lot in a conservation authority's regulated flood plain the authority may not permit a below-grade opening at all, which is one reason the mapping is checked first.
Does a separate entrance make my basement apartment legal?
No. It satisfies one requirement — a compliant exit — out of several. A legal unit also needs the zoning to permit it on that lot, the Building Code's ceiling height, fire separation, escape windows and alarms, a building permit and inspection, and in many municipalities registration with the town. The entrance is usually the first thing built because everything else in the basement is easier to do through it, but it is the beginning of the process, not the end.
Do I need conservation authority approval for a basement entrance?
Only if your property is inside a conservation authority's regulated area — the valleys, floodplains, wetlands and their allowances, which the authority maps online. Inside that area, excavating a stairwell is development under Ontario Regulation 41/24 and needs the authority's permission before the municipality can issue the building permit. Outside it, no. Checking the map takes minutes and it is the first thing we do on a lot near a creek or a ravine.