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Cast Iron Drain & Stack Replacement in Ottawa

Original cast iron in an older Ottawa home rusts from the inside out. We replace failing stacks and drains with modern ABS, planned around your house and your renovation, and we put the floors and walls back.

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Old vertical cast iron drain stack against the stone foundation wall of an older Ottawa basement

Signs your cast iron is failing

  • Rust-coloured weeping, stains or crusty patches on the stack or drain pipes
  • A crack or split you can see, often along the bottom of a horizontal pipe
  • Slow drains and repeat clogs, because rough, scaled pipe catches everything
  • Sewer smell near the stack or floor drain
  • A ceiling stain under a bathroom
  • Your house was built before about 1970 and the drains have never been replaced
Removed metal pipe section has heavy rust and a large lengthwise opening.
Badly corroded cast iron with a split along its length, removed from an Ottawa home

Why cast iron fails

Cast iron drains were standard in Ottawa homes until the 1970s, and many have lasted 60 to 100 years. Over time the inside corrodes and scales, which narrows the pipe. The bottom of horizontal runs thins out where water sits, and joints loosen. Pipe under the basement floor often fails first, because you can't see it until it lets go.

Stack, building drain or both?

  • The stack is the vertical pipe that runs from the roof to the basement. Every toilet and drain in the house ties into it.
  • The building drain runs from the base of the stack, usually under the basement floor, out through the foundation to the sewer line.

We camera both and tell you which parts are sound and which aren't. Sometimes replacing a failed section is enough. Sometimes the whole system is near the end and it makes sense to do it once, especially before a renovation closes the walls.

Alternate close view of the metal drain junction and connected pipes at floor level.
Original metal drain junction at floor level
Overhead drain connection with rubber transition couplings beside metal ductwork.
Replacement drain connections and couplings overhead

How the replacement works

  1. Camera and plan. We map what's there and agree the scope and price in writing.
  2. Protect the house. Floor protection, dust containment, and a plan for which toilets and sinks stay usable each day.
  3. Open up only what's needed. Wall access at the stack, and the basement floor where the building drain runs.
  4. Install ABS. New pipe and fittings to code, properly supported and vented, with a cleanout.
  5. Inspect and restore. Permit inspection, concrete re-poured, access closed up, site cleaned.

A stack replacement usually takes one to two days. A stack plus a building drain under the floor is often two to five days, depending on the house. One customer's 80-year-old pipe ran under boulders and took five days, and they still wrote that we explained everything along the way.

Is it time to replace your cast iron?

We'll camera your stack and drains and tell you honestly what needs doing now and what can wait.

Get Service(613) 294-0864

What it costs

Pricing depends on how much pipe is replaced, how many fixtures tie in, and how much floor or wall has to be opened. Replacing an old cast iron drain under a basement floor is typically around $4,500. A full stack-and-drain job costs more. You get one written price that includes the permit, the concrete and the clean-up.

Planning a renovation?

Replacing cast iron before new drywall and flooring go in is far cheaper than opening finished walls later. We regularly schedule around renovation contractors and finish while the walls are still open.

More from our cast iron jobs

Black vertical drain stack with angled upper connection inside exposed wall framing.
Black cast iron stack inside an opened wall
Black vertical drain stack connects to overhead fittings within exposed timber framing.
Stack and ceiling connections exposed
Dark metal drain junction, vertical pipes and rubber coupling against a tiled wall.
Old metal drain junction before replacement
Two light-coloured pipe runs with angled bends route into ceiling penetrations above ductwork.
New light-coloured drain runs overhead
Black drain pipe and angled elbow exposed beneath timber framing beside a hanging cable.
Black drain elbow below open ceiling
Dark drain piping runs beneath open joists above a basement window; backlit view.
Overhead basement drain piping by window
Open end of an old drain pipe shows dark internal buildup above a gravel floor trench.
Old drain pipe end with internal buildup
Rust-covered broken pipe sections rest on gravel beside protective sheeting.
Removed corroded pipe sections on gravel
Long old pipe section split along its length lies next to a floor excavation.
Split old pipe beside opened floor
Gloved hand holds a dark pipe cross-section with visible buildup around the bore.
Old pipe cross-section held in gloved hand

See all cast iron & stacks photos

What customers say about this work

★★★★★
“Michael and team were great to work with for our cast iron replacement in our older home. They were clear and open as things arose throughout the job, scheduled around our renovation, and ensured everything we needed got done. We will be using their services again.”
Mitchell S.Google review, 2026
★★★★★
“If you are looking for a knowledgeable plumber who provides friendly, efficient service, look no further than The Irish Plumber.”
Richard S.Google review, 2021
★★★★★
“Mike was efficient, professional and pleasant. We live in an older home and The Irish Plumber is our go to. They are always available on short notice and all of their staff is awesome. Recently, the Irish Plumber had to complete a big job for us. An 80-year old cast iron pipe underneath the ground cracked.”
Elizabeth D.Google review, 2025

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Questions Ottawa homeowners ask us

How long does cast iron pipe last?
Often 50 to 100 years, depending on water, use and installation. Many Ottawa homes built before 1970 are now at or past that point, especially for pipe under the basement floor.
Do I have to replace all my cast iron at once?
Not always. We camera the system and tell you which sections are sound. If one section has failed and the rest is solid, a partial replacement can make sense. If it's all near the end, doing it once saves money and disruption.
What do you replace cast iron with?
ABS plastic drain pipe, to the current Ontario Building Code, with proper supports, venting and a cleanout for future access.
Will my house be livable during the work?
Yes. We plan the job so you have a working toilet for most of each day, and we contain the dust and clean up daily.
Does insurance cover cast iron replacement?
Usually not for age-related wear, but sometimes for sudden damage the failure caused. We can give you photos, camera footage and an itemized invoice for your adjuster.
How much does cast iron pipe replacement cost in Ottawa?
Replacing an old cast iron drain under a basement floor is typically around $4,500. Stack replacements and larger jobs cost more. We give one written price after the camera inspection.

Replace it once, properly, before it lets go

A clear plan for your older home's drains, one written price, and floors and walls put back.

Get Service(613) 294-0864
Get Service(613) 294-0864