Shared Walls in a Townhouse: Noise, Repairs and Who Fixes What in Stoney Creek and Hamilton
A townhouse is attached to its neighbours. You share a wall, usually a roofline, and often a fence or a driveway. Nobody hands you a list of who looks after each one.
This guide covers the party wall, noise, fire separation, end units versus interior units, and who is responsible for the attached parts, with who confirms each answer before you buy.
What the party wall is
The party wall is the wall between your home and the one next door. Ontario's Building Code defines it as a wall jointly owned and jointly used by two parties, built on the line between two parcels of land, under an easement agreement or a right in law.
- Freehold townhouse. The lot line typically runs through the wall. What each owner may do to it depends on what is registered on title, such as a party wall agreement or easements. Your real estate lawyer confirms that in the title search.
- Condo townhouse. The corporation's declaration and description set where your unit ends and the common elements begin, and who maintains and repairs each. Our guide to freehold, condo and common-element townhouses explains the three types.
Noise: what the code requires and what to check
How much sound comes through depends on how the wall was built, and that varies by age and builder. Ontario's 2024 Building Code, in effect since January 1, 2025, sets a minimum between dwelling units: an apparent sound transmission class (ASTC) of 47 for the wall and the construction around it, or a wall rated STC 50 with specified adjoining construction. These are minimums for airborne sound, not a promise of silence. An older row was built to the rules of its time.
- Visit more than once, at different times of day, including an evening.
- Stand in each bedroom with the home quiet. Turn off fans and music.
- Ask which rooms are on the other side of the wall. A neighbour's stairs or living room beside your bedroom matters more than a closet.
No visit proves a home is quiet. You hear one set of neighbours on one day.
Fire separation and alarms
The party wall is also a fire separation. For side-by-side townhouses on a property line, the Building Code requires at least a one-hour fire-resistance rating, continuous from the top of the footings to the underside of the roof deck.
Where the attic is accessible, an inspector can look there for gaps or openings in the separation. Our home inspection guide covers what else an inspection includes.
Ontario requires a working smoke alarm on every storey and outside all sleeping areas. Since January 1, 2026, a home with a fuel-burning appliance, a fireplace or an attached garage also needs a carbon monoxide alarm on every storey, as well as beside each sleeping area.
End unit or interior unit
An end unit has one shared wall, more windows, and often a side yard that leads to the back.
An interior unit has two shared walls. Its backyard may be reachable only through the house or the garage. Some rows have a rear access easement instead: a registered right to cross part of the neighbouring lots to reach your own yard. Registered easements stay with the land when it is sold. Your lawyer confirms on title that one exists and where it runs. A gate in the fence is not proof.
Who fixes what
| Item | What to ask or check | Who confirms it |
|---|---|---|
| Party wall | Any party wall agreement or easement on title. Gaps in the attic separation. | Lawyer, inspector |
| Roof | Age, and when the neighbours last did theirs. Staining near the joint between homes. | Seller, inspector |
| Fence | Who built it, its condition, and any arrangement with the neighbour. | Seller |
| Driveway | Is any part shared, and is the right of way registered. | Lawyer |
| Backyard access | Through the house only, or by a registered easement. | Lawyer |
| Any of these in a condo townhouse | What the corporation maintains and repairs. | Condo documents, lawyer |
Roof. A row usually sits under one continuous roof. On a freehold row there is no corporation to organise the work, so new shingles or a leak at the joint means agreeing on timing, contractor and cost with the owner next door.
Fences. Ontario's Line Fences Act gives neighbours a way to settle who pays for a boundary fence, but a municipality can replace it with its own by-law. Hamilton has done that inside its urban boundary with a division fence by-law. Neighbours can agree to any split. Without an agreement, the by-law sets the neighbour's share of a new or replacement fence at half the actual cost or half the material cost of a basic chain-link fence, whichever is less. Repairs are split equally unless one owner caused the damage. Confirm the current by-law with the City before you rely on it.
Driveways. A shared driveway depends on a right of way registered on title. Our guide to townhouse parking, yards and rules covers the rest.
Insurance
Each freehold owner insures their own home. The Insurance Bureau of Canada describes a homeowner policy as covering the building and its contents, with sewer backup and overland flood as optional coverages. A fire or burst pipe next door can still damage your side, so ask a broker how your own policy would respond. Our wet basement guide covers water damage. In a condo townhouse, the corporation generally insures the units and common elements, but not improvements made to a unit.
Who should be careful with a townhouse
- Light sleepers and people who work nights. Neighbours live normal daytime lives. An end unit or a detached house may suit you better.
- Buyers of older rows. Keep the inspection condition. Our guide to making an offer explains how conditions work.
- Interior-unit buyers who move equipment to the backyard. Confirm the access route before you offer.
- Buyers who dislike negotiating repairs with neighbours. A freehold row requires it. A condo townhouse moves that work to the corporation, for a monthly fee.
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Frequently Asked Questions
How soundproof are townhouse walls in Ontario?
The 2024 Building Code sets a minimum of ASTC 47, or STC 50 with specified adjoining construction, between dwelling units. Older townhouses were built to earlier rules, so listen in person.
Who pays for a shared roof on a freehold townhouse?
There is no corporation to organise or pay for it. Each owner generally looks after the roof over their own home, and repairs at the joint between two homes have to be arranged with the neighbour.
Who pays for a fence between neighbours in Hamilton?
Neighbours can agree to any split. If they cannot agree, Hamilton's division fence by-law sets a default inside the urban boundary. Confirm the current rules with the City.
Is an end unit townhouse better than an interior unit?
It has one shared wall, more windows and often direct access to the backyard. An interior unit has two shared walls, and yard access may depend on an easement.
Do townhouses need carbon monoxide alarms in Ontario?
Yes, if the home has a fuel-burning appliance, a fireplace or an attached garage. Since January 1, 2026, alarms are required on every storey and beside each sleeping area.
Want to talk through the shared walls, roof or access for a specific townhouse? Get in touch and we will go through it with you.
This guide is general information, not legal, insurance or building advice. Codes and by-laws change, and every title and condo declaration is different, so confirm the details with your lawyer, inspector and insurance broker.