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How to winterize an older Cambridge house: a fall checklist from the basement up
Older Cambridge houses lose heat and freeze pipes in predictable places. Galt's century brick, the post-war bungalows in Preston and the mill-era frame houses in Hespeler all have them. This checklist goes from the water line to the attic in the order that matters, based on guidance from the City and Natural Resources Canada.
Last updated September 25, 2026 · Reviewed by the Handyman Cambridge team
Start with the water: know which pipe is yours
The City of Cambridge owns the water pipe from the watermain to your property line. From the property line into the house, the pipe is yours, and so is any damage when it freezes or bursts inside. The water meter belongs to the City and is usually in the basement. Your main shut-off valve is usually right beside it.
Before the first hard frost:
- Find and test the main shut-off. Turn it off and on once so you know it moves. In older houses, a seized valve is common. Replacing one is plumber's work.
- Shut off and drain outdoor taps. Unscrew the hoses, close the interior valve that feeds each outdoor tap, then open the outside tap to let it drain.
- Insulate exposed pipes near outside walls and in crawl spaces, unheated rooms and the garage. Foam pipe sleeves are a simple fix where the pipe is accessible.
- Keep the garage door closed if water lines run through the garage.
If you are away for a long stretch, the City of Toronto's guidance is to close the main valve and open a cold-water tap in the basement to drain the lines. If a pipe does freeze, never use a torch or open flame to thaw it. If you cannot find the frozen section or cannot thaw it, call a licensed plumber.
Understand where the heat goes
Natural Resources Canada's air sealing guidance explains the stack effect. Warm air rises and leaks out at the top of the house, pulling cold air in at the bottom. So the leaks that matter most sit at both ends: the attic and upper ceiling, and the basement and rim joist. Windows and doors in the middle are the ones you can feel, but they are only part of the story.
The checklist, bottom to top
Basement
- Seal gaps where pipes, wires and vents pass through the foundation or rim joist.
- Check the rim joist, where the floor framing sits on the foundation. Natural Resources Canada lists it among the main leak points at the bottom of a house.
- Look for foundation cracks. Seal small non-structural ones. Anything wide, growing or wet needs a foundation contractor.
Main floor
- Exterior doors: replace flattened weatherstripping and worn door sweeps. Adjust the strike so the door pulls tight to the stop.
- Windows: caulk the gap between the trim and the wall inside. Outside, caulk cracks that would let water or insects in. On Galt's original double-hung windows, weatherstripping the sashes and fitting storms often does more than caulk alone.
- Storm doors: tighten or replace closers so they latch in wind.
Top floor and attic
- Attic hatch: Natural Resources Canada says to treat it like an exterior door. Weatherstrip the edge, and add hooks and eyes or a latch so the panel is held tight against the seal. Insulate the back of the panel too.
- Ceiling penetrations: gaps around light fixtures, bath fans and plumbing stacks leak warm, moist air into the attic. Around chimneys and other heat sources, use a non-combustible sealant. Silicone or polysulphide usually works.
Outside
- Re-caulk failed joints around windows and doors, and where different materials meet.
- Extend downspouts so meltwater drains away from the foundation.
- Put storm windows back in and check their latches.
One warning about sealing a house tightly
Natural Resources Canada warns that as a house gets tighter, less air is available for fuel-burning appliances. If a furnace, water heater or fireplace does not get enough air, the chimney or flue can spill combustion gases back into the house. If you are doing a lot of sealing in a house with an older gas furnace, water heater or wood stove, have a registered gas technician check venting and combustion air. Make sure your CO alarms work before winter.
What the handyman does and does not do here
A fall visit under caulking, weatherproofing and winter prep covers the carpentry and sealing side. That includes interior and exterior caulking, door sweeps and weatherstrip, attic hatch sealing, storm closers, draining outdoor taps, pipe sleeves on exposed lines, and extending downspouts. Sticking sashes and broken cords on older windows fall under century-home small repairs.
It does not include replacing a seized shut-off valve or a frost-free outdoor tap in the wall, thawing a frozen line inside a wall, or anything on the furnace or water heater. Those go to a licensed plumber or gas technician, and the written price will say so.
When to book
Caulk needs dry weather and temperatures above the minimum on the tube to cure properly, so exterior work is best done in September and October. Send the list with photos of the doors, windows and attic hatch. Say whether the house is in Galt, Preston or Hespeler and roughly when it was built. The Cambridge cost guide has planning ranges for a fall visit. Send your list here.