Late-Fall and Winter Excavation in Ontario: What Can Still Get Done
Yes, a lot of excavation work can still get done in late fall and winter in southwestern Ontario. Digging footings, trenching for services, demolition, land clearing and hauling often carry on as long as the site is planned for the cold. What usually waits for spring is finish work: final grading, topsoil, sod and anything that needs dry, unfrozen soil.
Here's how we think about cold-season digging around London, St. Thomas, Strathroy and the surrounding area. It also covers a locate rule change that takes effect November 1, 2026.
What makes sense to dig in late fall and winter
Cold weather isn't a hard stop. Some jobs suit the season well.
Footings and foundations for additions and garages. Digging ahead of a spring build keeps the schedule moving, as long as the excavation and any concrete are protected from frost.
Trenching for water, sewer, hydro and gas services. Lines need enough cover to stay below frost, and winter is a good time to get them in before landscaping.
Pool removal and fill-in. Late fall is a popular time to remove an old pool so the fill settles over winter.
Land clearing and brush removal. Leaves are down, so visibility is better. In the deep cold, frozen ground can actually support equipment better than mud.
Demolition of sheds, old decks, patios and outbuildings.
Hauling and stockpiling fill or aggregate for a spring project.
What's usually better in spring
Final grading and lot grading certification. Frozen, lumpy soil can't be graded accurately. Our post on lot grading in London explains why getting slopes right matters.
Topsoil, sod and seed. Sod needs unfrozen soil to root.
Interlock and patio bases. Gravel base needs to be placed and compacted on unfrozen ground. See our interlock base prep guide.
Drainage work in saturated clay. In the wettest stretch of late fall, heavy equipment can rut and compact clay soils, which makes drainage worse.
Frost: the biggest cold-weather factor
Frost affects two things: how hard the digging is, and how well whatever you build holds up.
Digging through frost
Once the top layer freezes, breaking through it takes more time and wear on equipment. Sometimes it needs a ripper tooth or ground thawing. Snow cover acts as insulation, so a snowy winter can mean shallower frost than a cold, bare one.
Protecting what you build
Footings and pipes need to sit below the frost line or be insulated. As one local example, a geotechnical report filed with the City of London for a site on Wharncliffe Road recommended that footings exposed to freezing be protected by at least 1.2 m (4 ft) of soil cover or equivalent insulation. It recommended the same minimum cover for water and sewer lines outside heated areas. The same report said fresh concrete placed in cold weather must be covered with insulating blankets. Your engineer or designer sets the requirements for your job, but those figures show why frost depth matters here.
Practical cold-weather rules we follow:
Never place footings or slabs on frozen soil.
Protect the bottom of an open excavation from freezing overnight with insulation or by backfilling promptly.
Keep stockpiles covered or shaped so they don't freeze into one solid block.
Plan for snow removal on site so trucks and equipment can move safely.
Locates: a rule change on November 1, 2026
Before any digging, every underground utility has to be located. Through Ontario One Call, locates are free. Standard requests are completed within 5 business days, and large projects within 10.
Two things matter for winter projects:
Validity period: under the Ontario One Call rules, a locate is valid for 60 calendar days. You can't start or keep digging after it expires. On long or slow winter projects, that window can run out.
New continuation option: a new regulation under the Ontario Underground Infrastructure Notification System Act takes effect November 1, 2026. It lets excavators keep digging for up to 180 days from the last locate document if certain conditions are met. The site can't have transmission infrastructure. Digging must stay at least 1 m below the lowest located infrastructure, and the excavator must keep care and control of the site. A statement and undertakings must go to Ontario One Call 10 to 15 days before expiry, and the locate documents must be kept on site. Using it is optional. Ontario One Call's announcement has the details.
Remember too that public locates don't cover private lines you own, like power to a garage, a gas line to a BBQ, or a septic system. Those need a private locator.
Moving soil off site in winter
If your project creates excess soil, Ontario's O. Reg. 406/19 (On-Site and Excess Soil Management) still applies in winter. In plain terms:
Excess soil going to a reuse site needs that site's written consent, and hauling records have to be kept.
Larger projects, projects on sites with higher-risk past uses, and remediation projects have extra planning and registry steps.
Some low-risk residential and small projects are exempt from parts of the planning rules.
Our excavation checklist goes into locates, excess soil and site prep in more detail.
Cold-season excavation checklist
Before you book a late-fall or winter dig, run through this list:
Locates requested at least 5 business days ahead, with a plan if the job may outlast 60 days.
Private locates booked for any homeowner-owned lines.
Access route that can take a loaded truck when wet or frozen, with ground protection if needed.
Plan for frost protection of footings, slabs and open trenches.
Spot picked for stockpiles and snow piles that won't block drainage.
Excess soil destination confirmed, with records kept.
Spring follow-up booked for final grading, topsoil and sod.
The southwestern Ontario angle
Our clay soils around London and Middlesex County hold water. In practice, a wet November can be harder on a job site than a cold, dry January. When ground is saturated, we may pause, use mats, or reschedule so we don't rut your lawn and compact the soil. Near the Lake Huron shoreline and in snow-belt areas like Grand Bend and Goderich, lake-effect snow can stop work for a day or two. We build that into the schedule. Browse our services to see the full range of site work we handle year-round.
FAQ
Can you excavate in winter in Ontario?
Yes, many excavation jobs can be done in winter with the right equipment and planning. Frozen topsoil takes more effort to break, and some finish work like grading, sod and concrete is better done once temperatures rise. Wet, muddy shoulder-season weather is often harder on a site than steady cold.
How long are Ontario One Call locates valid?
Under Ontario One Call's rules, the locate validity period is 60 calendar days, and you can't start or continue digging after it expires. A new regulation taking effect November 1, 2026 lets excavators who meet certain conditions keep digging for up to 180 days from the last locate document.
How deep does frost go in London, Ontario?
It varies by winter, snow cover and soil type. As one example, a geotechnical report filed with the City of London recommended at least 1.2 m (4 ft) of soil cover, or equivalent insulation, to protect footings exposed to freezing. Your designer or engineer will set the depth for your project.
Is it cheaper to excavate in winter?
Not necessarily. Some contractors have more availability in the off-season, but cold-weather work can need extra steps like frost breaking, ground thawing, insulated blankets or snow clearing. Get a written quote for your specific job.
Can I pour concrete footings in winter?
Concrete can be placed in cold weather with precautions. Fresh concrete has to be protected from freezing, often with insulating blankets, and it should never be placed on frozen ground. Follow your engineer's and concrete supplier's directions.
Talk to SPM Landscape & Excavation
Planning a dig before freeze-up, or lining up a job for early spring? We'll tell you honestly what makes sense now and what should wait. SPM has served London and southwestern Ontario since 2006, is WSIB covered and carries $1M in liability insurance. Call (519) 474-0008, email spmlandscape@gmail.com, or visit us at 791 Manchester Rd, London, ON.
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