A semi-detached home inspection covers everything a detached-house inspection does, plus the parts you share with the house next door: the party wall, the roof line where the two halves meet, sometimes a chimney, a driveway or even a drain. In Toronto, Mississauga and Brampton, semis are one of the most common ways buyers get into a freehold home, and most of the surprises we find sit right at that shared line. Your inspector is Yama Nehan, a Certified and Registered Home Inspector with 15 years of home inspection experience. To book, call 647-704-7100 or book an inspection online.

Key takeaways

  • You own your half of a semi, but the roof, wall and sometimes the drains behave like one building. Problems on the neighbour’s side can show up on yours.
  • The party wall is the first thing to look at, from the basement all the way up into the attic.
  • Older Toronto semis (often brick, 1900s to 1950s) and newer suburban semis in Mississauga and Brampton (1970s onward) have very different weak spots.
  • Uneven roof replacements, one-sided basement work and shared sewer lines are the items buyers most often miss.
  • A home inspection is visual and non-invasive. We note what needs a specialist, such as a sewer camera scope, so you can follow up before your condition date.

What makes a semi-detached home different to inspect?

A detached house stands on its own. A semi shares one wall, and usually one continuous roof, with its neighbour. That means the condition of your home partly depends on how the other owner has looked after theirs. When I inspect a semi, I spend extra time where the two homes join, because that is where water, fire separation, sound and structural movement all meet. The rest of the inspection follows our full home inspection process: structure, roof, exterior, electrical, plumbing, heating and cooling, insulation and interior. If you want the full scope, see what a home inspection includes in Ontario.

Older Toronto semi vs newer Mississauga or Brampton semi

The age of the home changes what I look for more than the city does. Here is how the two most common types compare.

Area Older Toronto semi (Leslieville, the Danforth, East York, the Junction, parts of Etobicoke) Newer suburban semi (Mississauga, Brampton, Vaughan, Markham, Oshawa)
Party wall Usually solid brick. We look for cracks, missing mortar and whether the wall carries on through the attic or stops short. Usually framed or block with drywall. We look at the attic and garage side for gaps, holes cut for wiring or ducts, and missing drywall.
Roof Often two different roof jobs meeting at the centre line, sometimes with a step or a seam that relies on flashing or sealant. One roof built at the same time, but each owner may have replaced their half in a different year with different shingles.
Foundation Stone, rubble or old brick foundations, and possible underpinning or basement lowering done on one side only. Poured concrete or block. We look for settlement cracks, especially near the shared wall and the garage.
Drains Some older semis share a sewer line under the property, and many have clay or cast iron drains. Usually separate laterals with plastic drain pipe, but the grading between homes is often tight.
Electrical Older wiring types, small panels and amateur upgrades are common in homes of this age. Generally modern, but finished basements and added units can bring unpermitted wiring.
Chimney and venting A shared brick chimney on the party wall is common, sometimes no longer in use. Mostly direct-vent furnaces and water heaters. We check vent clearances to windows and the neighbour’s side.

For more on homes from the early and mid-1900s, read our guide to older home inspections in Toronto.

The shared wall: what a home inspector checks

The wall between two semis is meant to slow fire and sound from passing from one home to the other. In newer semis it is built as a fire separation between the two dwellings, and it should run continuously up to the underside of the roof. In older homes, what was built and what has been changed since varies a lot.

  • In the attic: Is the separation continuous, or is there an opening where you can see straight into the neighbour’s attic? Have holes been cut for wiring, ducts or bathroom fans and left open?
  • In the basement: Cracks, damp patches or efflorescence (white mineral deposits) along the party wall, and signs that the neighbour has lowered or underpinned their basement.
  • Inside the living space: Cracks that follow the line of the shared wall, sloped floors toward or away from it, and doors that stick on that side of the house.
  • In an attached garage: The wall and ceiling between the garage and the house should be intact, with no gaps or missing drywall.

I report what I see. If the attic separation has gaps or the party wall shows movement, the report says so plainly, with photos, so you can get a contractor’s quote before your condition date.

The roof line where two homes meet

A situation we often see on semis across Toronto, Mississauga and Brampton: one owner replaced their half of the roof a few years ago and the other half is original. The new shingles meet the old ones at the centre line, and the seam between them depends on how carefully the roofer tied the two together. That seam is a common spot for leaks that show up as stains on the top-floor ceiling or in the attic sheathing along the shared wall.

During the inspection I look at both halves from the outside, the flashing and any step at the party wall, the eavestroughs and downspouts on both sides, and the attic underneath for stains, damp insulation or daylight. I can only inspect your side’s attic, but the condition of the neighbour’s roof is still visible from outside and worth noting, because water does not respect property lines.

Basement, foundation and drainage

Semis sit close to their neighbours, and on many Toronto streets the side yard is barely wide enough to walk through. That makes grading and downspouts more important than on a detached lot.

  • Downspouts from either house that empty into the narrow gap between homes.
  • Grading that slopes toward the foundation on the shared side or the side path.
  • Basement moisture, stains and musty smells along the shared wall.
  • One-sided basement lowering or underpinning, which can leave a visible step or new cracks at the party wall. Ask the seller for any paperwork on that work.
  • Drain type and condition where visible. On older semis, I usually recommend a sewer camera scope, because some share a line with the house next door and clay or cast iron pipes can be cracked or root-damaged.

Many semis in Brampton and Mississauga now have a second unit in the basement. If the home you are buying does, read our guide to basement apartment home inspections in Brampton and Mississauga.

Semi-detached home inspection checklist

Bring this list to your inspection, or use it to read your report.

  • Party wall continuous in the attic, with no open holes into the neighbour’s side
  • No major cracks, bulges or water stains along the party wall in the basement
  • Roof seam at the centre line tight, flashed and free of leaks below
  • Age and condition of your half of the roof, and visible condition of the neighbour’s half
  • Shared chimney: in use or not, capped, mortar and flashing in good shape
  • Eavestroughs and downspouts on both sides draining away from the foundation
  • Side-yard grading sloping away from the house
  • Signs of one-sided underpinning or basement lowering
  • Drain type, and whether a sewer camera scope is recommended
  • Electrical panel, wiring type and any amateur upgrades
  • Furnace, water heater and vent clearances, including toward the neighbour’s windows
  • Garage-to-house separation if there is an attached garage
  • Insulation and ventilation in the attic

Older semis can also contain materials such as vermiculite attic insulation or asbestos-containing products. If you have concerns, we can arrange home hazard testing alongside the inspection.

Questions to ask the seller or your agent about a semi

  • When was each half of the roof last replaced?
  • Has either side had basement lowering, underpinning or waterproofing done?
  • Is the sewer line shared with the neighbour?
  • Is the driveway or side path shared? This is a question for your real estate lawyer, since it depends on the title.
  • Has the house had any water in the basement, and on which wall?

How much does a semi-detached home inspection cost?

Home inspections with Golden Home Inspections start from $499. The final price depends on the property, mainly its size, age and whether there is a basement unit or added services such as hazard testing. For the full breakdown, see our guide to home inspection cost in Toronto and the GTA. You get a written report with photos within 24 hours.

Booking a semi-detached home inspection in the GTA

We inspect semis in Toronto, Mississauga, Brampton, Vaughan, Markham, Richmond Hill, Oakville, Pickering, Ajax, Whitby and Oshawa. For city-specific details, see home inspection in Toronto, home inspection in Mississauga and home inspection in Brampton. If you are comparing a semi with a townhouse, our freehold vs condo townhouse inspection guide covers the differences.

Whoever you hire, choose your inspector carefully: ask about their certifications, their experience with homes like the one you are buying, and to see a sample report. Call 647-704-7100, email contact@goldenhomeinspections.ca or book your inspection online. We are open 9 AM to 8 PM, seven days a week.

Semi-detached home inspection FAQ

Does a home inspector check the neighbour’s side of a semi?

No. We inspect the home you are buying. We do note anything visible from your property that could affect your home, such as the condition of the neighbour’s roof, downspouts or grading.

What is the most common problem in semi-detached homes?

In our experience, the most common issues sit at the shared line: leaks at the roof seam where two different roofs meet, gaps in the attic separation, and moisture along the party wall in the basement.

Should I get a sewer camera scope on a semi?

On older semis, especially in Toronto neighbourhoods built before the 1960s, it is usually worth it. Some older semis share a sewer line, and older clay or cast iron pipes can be damaged by roots or cracks that a visual inspection cannot see.