Why this matters
Water expands as it freezes, and a pipe packed with ice can split along its length. The split often goes unnoticed until the ice thaws, at which point water pours from a wall, a ceiling or a crawlspace. Winters in Markham regularly bring stretches well below freezing, often with wind that drives cold into exterior walls and garages.
Pipes at risk are predictable: those on outside walls, in unheated garages and crawlspaces, beneath kitchen sinks on exterior walls, and the short lines feeding outdoor taps. Older side-split and back-split homes, common in parts of Thornhill and Milliken Mills, tend to have more of these weak spots than newer builds.
Insulation, heat tape and drip strategies
| Method | Best for | Notes |
|---|---|---|
| Foam pipe insulation | Accessible pipes in basements, garages and crawlspaces | Inexpensive, and slows heat loss; it does not add heat |
| Heat cable (heat tape) | Short exposed runs in unheated spaces | Use only listed products and follow the manufacturer's instructions closely |
| A slow drip | Taps on exterior walls during severe cold | Moving water is harder to freeze and relieves pressure |
| Open cabinet doors | Sinks on outside walls | Lets warm room air reach the pipes |
Gear past the DIY stage
- Pipe cutter, deburring tool and propane torch.
- PEX crimp and expansion tools.
- Push-fit couplings for temporary repairs.
- Moisture meter and thermal camera.
Step by step
- In autumn, shut off and drain outdoor taps from inside, and disconnect hoses.
- Insulate exposed pipes in the garage, crawlspace and basement rim joist.
- Seal drafts where cables and pipes pass through exterior walls.
- Keep the thermostat steady overnight and when you are away; avoid deep setbacks during cold snaps.
- On the coldest nights, open cabinet doors under exterior-wall sinks and let a tap drip.
- If a tap produces only a trickle in freezing weather, assume a partial freeze and act at once.
If you suspect a frozen line, open the affected tap so meltwater can escape, then warm the pipe gently, starting nearest the tap and working back. Keep a hand on the main valve in case thawing reveals a split.
Handing it over to us
Call us if you cannot locate the frozen section, if the pipe sits inside a finished wall, or if thawing reveals a leak. A pipe that has burst needs the water shut off at once; our guide to the first ten minutes of a burst pipe sets out the steps. A slow bathroom drain on an outside wall can also freeze in cold weather, and bathroom sink drain repair covers that kind of fix.
Homes on larger, exposed lots, such as those around Angus Glen, often have long runs to garages and outdoor taps that deserve extra attention each autumn.
Markham note: village-core houses tend to hide cast iron and galvanized behind plaster, while Cornell and Box Grove builds run PEX to a manifold. We ask the year your house was built so the right fittings ride along on the truck.
Straight from the phone log
At what temperature do pipes freeze?
There is no single number. Exposure, wind and insulation matter as much as the air temperature. Pipes on exterior walls are at risk in sustained cold well below freezing.
Should I leave taps dripping all winter?
Only during severe cold snaps, and only at taps on exterior walls. A slow drip from cold and hot is usually enough.
Is heat tape safe?
Listed products installed exactly as the manufacturer directs are designed for the purpose. Never overlap cables unless the instructions allow it, and inspect them each autumn.
Ready to get it fixed?
One call, a clear explanation, and work finished tidily before we leave.