Guide · Pipes, leaks & valves
Grey Poly-B Pipe in Markham Houses
Grey plastic water pipe was common in houses built between roughly 1978 and 1995. Some of it is still behind Markham walls.
- A plumber answers when you call
- Clear price before any pipe is cut
- Basements left as clean as we found them
The Markham angle
Markham grew quickly through the 1980s and early 1990s. Subdivisions in Milliken Mills, Middlefield, Markville, Raymerville and parts of Unionville went up during exactly the years when grey polybutylene (Poly-B) supply line was in common use across Canada. Many of those homes have since been repiped. Many have not.
Poly-B was cheap and easy to install. Over time, though, it gained a reputation for failing without warning, often at fittings, and particularly where chlorinated water and heat combine. Insurers took notice, and some now ask about it, raise premiums or limit coverage for homes that still have it.
One step after another
- Begin at the water heater. Check the pipes leaving the top of the tank and near the main shut-off. Poly-B is usually flexible, grey and stamped with a code such as PB2110.
- Check the fittings. Early installs used plastic fittings; after that, installers switched to metal crimp bands. Plastic fittings are considered the weaker of the two.
- Look under sinks. Grey pipe coming out of a wall to a vanity supply valve is a strong hint.
- Do not confuse it with PEX. PEX is the modern replacement and is often white, red or blue. Grey is not an automatic answer, so read the printing on the pipe.
- Ask your insurer. Find out whether Poly-B affects your coverage now, and whether that is likely to change at renewal.
Slip-ups we see often
- Replacing just one leaking section and assuming the rest is fine. Pipe of the same age tends to share the same weaknesses.
- Leaving water pressure high. Excessive pressure strains every fitting, so ask about a pressure-reducing valve if yours is unusually strong.
- Waiting until a fitting lets go while you are on holiday. Planned repiping is far tidier than flood repair.
- Hiding Poly-B when selling. Buyers' inspectors look for it, and it is better discussed early.
What replacement involves
Most Markham repipes swap Poly-B for PEX, run in new routes through basement ceilings and up interior walls. Crews open small, targeted holes in drywall rather than tearing out whole rooms, then patch them once the new lines are tested. A typical detached house is often done over a few days, with water restored each evening when possible.
Because the job touches every fixture, it is a sensible time to add new shut-off valves under each sink and toilet and to replace an old main valve.
Time to pick up the phone
Call if you suspect Poly-B, if your insurer has asked about it, or if you are buying a house built in that era. We can confirm what you have and give a written plan for Poly-B replacement or full repiping. Our brief on buying an older Markham home lists other things worth checking at the same time.
Excessive pressure strains every fitting, so ask about a pressure-reducing valve if yours is unusually strong.
From the job notes of Plumbers in Markham
Guide · Pipes, leaks & valves
Signs to watch for
- The meter dial turns with every tap off
- Flow that falls off when a second tap opens
Call a plumber when
- Water is reaching a ceiling, wall cavity or electrical panel
- Sewage is coming up through a floor drain or toilet
- You smell gas near the water heater: leave and call the gas utility first
- A valve will not close or a fitting keeps weeping after tightening
Markham note. Markham water service lines enter on the street-facing basement wall, and the main shut-off and meter usually sit right there. In older houses that valve is often a rusty multi-turn gate valve left untouched since the house was built.