Raising a Cottage and Installing an ICF Foundation in Ontario: A Professional Guide

Raising a Cottage & Installing an ICF Foundation in Ontario: What You Need to Know
Putting a proper foundation under an old cottage is one of the highest-value upgrades in cottage country – it ends the wobbly-pier era and turns a seasonal cabin into a warm, four-season home. It is also a serious, engineered project: lift the cottage, remove the old foundation, build a new insulated concrete form (ICF) foundation, pour a new floor (with an option for radiant heat), and set the cottage back down. This is a professionals-only job. Here is exactly how it goes, what it costs in Ontario, the risks, and the code you have to satisfy.
The project in four stages
Every cottage-lift-and-refoundation job follows the same arc, and the order matters. Rushing a stage – especially concrete cure time – is how projects go sideways.
- Lift. Steel beams and synchronized hydraulic jacks raise the cottage a few inches at a time onto timber cribbing, high enough to work underneath.
- Remove and excavate. The old block piers, walls, and any slab come out, and the crew digs below the frost line for new footings.
- Rebuild. New footings, ICF walls, waterproofing and drainage, then a new insulated floor slab (with radiant tubing if you want a warm floor).
- Lower and reconnect. Once the concrete has cured, the cottage is set down onto anchored sill plates and tied to the new foundation, then utilities are reconnected.
Stage 1: Planning and preparation
Structural review
An engineer checks whether the cottage can take the lift – rotten sill beams, weak joints – and specifies any bracing or reinforcement needed so the structure holds together while it is in the air.
Disconnect and prep
The area is cleared and utilities (water, power, gas, septic) are safely disconnected or rerouted. Anything running through the old foundation is cut before the lift, and a temporary plan covers the gap.
Building permit + stamped plans
Raising a structure and replacing a foundation needs a building permit. Ontario municipalities generally require plans stamped by a Professional Engineer or a BCIN designer, since lifting a house is a structural alteration.
Conservation authority
On a lake or river lot, the local conservation authority may need to sign off, and zoning can limit how much you change the building’s height or footprint – confirm early.
Stage 2: Lifting the cottage
This is the part that looks alarming and is pure engineering. Experienced house movers slide long steel I-beams under the cottage (often through openings cut in the skirting or old wall), then raise it with synchronized hydraulic jacks controlled from one point to keep the whole building level.
- Jack and crib, over and over. The house comes up only a few inches at a time – best practice is no more than about 6 inches per jack station – then timber cribbing is stacked under the beams to hold the gain before the jacks reset. At any pause, the cottage rests on the cribbing, not the jacks.
- Constant leveling. Dozens of points are measured to avoid twisting the frame. Most lifts go just high enough to work underneath (often 3 to 8 ft); a full new basement can mean a much taller lift.
- Then it waits. At final height the cottage sits on cribbing and beams for the duration of the foundation work, monitored for stability, with an open workspace beneath.
Stage 3: Removing the old foundation and excavating
With the cottage supported overhead, the old block piers or walls and any concrete slab come out. Crews knock down masonry course by course, break up and haul out the old slab, then excavate to the required depth for the new footings – often with a mini-excavator driven under the raised house, or dug from the sides if the lift is high enough.
All the broken concrete and block is binned and hauled to a recycler or landfill, and disposal fees are part of the budget. Cribbing towers are placed just clear of the new wall line so digging can proceed around them; any support in the way of a new wall is relocated once enough of the foundation is built to take the load.
Stage 4: Installing the new ICF foundation
This is the core of the job – a steel-reinforced concrete wall built inside stay-in-place foam forms, so it comes insulated. The sequence:
- Footings. Concrete footings are poured below frost depth with rebar per the engineering. An inspector usually checks the footing forms and rebar before the pour, and the footing cures before the walls go up.
- Stack the ICF blocks. The foam forms interlock like large hollow blocks, stacked in a staggered running bond along a chalk line on the footing. Window, vent, beam-pocket, and service openings are boxed out as the wall rises.
- Reinforce and brace. Vertical and horizontal rebar goes in per the engineer’s design (the OBC sets minimum rebar size and spacing for ICF walls), then a bracing and scaffold system keeps the walls plumb for the pour.
- Pour the walls. A pump truck places the concrete (commonly 25 MPa or higher) in lifts to control form pressure, vibrated to remove voids. Anchor bolts or straps for the sill plate are set into the wet top of the wall. Then it cures – often around 10 days before the cottage can come back down.
- Waterproof and drain. The below-grade foam gets a damp-proofing membrane or drainage board, and a perimeter weeping tile at footing level leads to a sump or daylight – critical for Ontario’s wet, near-water lots.
- Backfill. Clear stone around the weeping tile, then soil filled and compacted in layers, with bracing left on until enough backfill is placed to protect the new walls.
Stage 5: The new floor slab (and optional radiant heat)
Inside the new foundation, the crew levels the ground, lays a compacted gravel base, then rigid under-slab insulation (often 2 in / R-10) and a 6 mil poly vapour barrier – both expected by the code and good practice, especially for a heated slab. Ontario’s radon rules also mean a sub-slab depressurization rough-in (a perforated pipe in the gravel to a capped riser) goes in at this stage.
If you want a warm floor, this is when PEX radiant tubing is laid in a serpentine pattern (typically 6 to 12 in spacing), tied down and pressure-tested before the pour. Ready-mix concrete – usually a 4 in slab – is placed over the insulation, vapour barrier, and tubing, screeded, and finished, then cured (walkable in a day or two, full strength around 28 days).
Stage 6: Lowering and reattaching the cottage
Once the walls and slab have cured, the movers reverse the process – setting treated sill plates on the new walls, then lowering the cottage in small increments onto them while monitoring every side to keep it level. The framing is anchored to the sill plate and foundation (bolts tightened, straps fastened), gaps are shimmed and sealed, beams and jacks come out, and the openings cut for the beams are patched.
After the cottage is seated, plumbers and electricians run new lines through the foundation, the basement can be insulated and finished, and the lot is regraded and repaired. The lowering is normally included in the lifting contract; utility reconnection and interior finishing are separate lines.
What it costs in Ontario (2026)
Every cottage and lot is different, but here is a realistic breakdown of professional charges. Ranges reflect 2026 Ontario market data – confirm with detailed quotes.
| Stage | Typical cost (2026) | Notes |
|---|---|---|
| Lifting (up + lowering) | $15,000 – $30,000 | Beams, jacks, cribbing, crew; small cottage from ~$10-15k |
| Old foundation removal + excavation | $5,000 – $15,000 | Depends on concrete volume and dig depth; often bundled into the foundation quote |
| New ICF foundation | $30,000 – $60,000 | Blocks, footings, concrete, rebar, waterproofing, drains, backfill |
| New floor slab (+ optional radiant) | $7,000 – $15,000 | ~$8/sq ft plain, ~$12-15/sq ft heated with insulation and PEX |
| Permits, engineering, utilities | $3,000 – $10,000 | Stamped plans, permit fees, reconnections and inspections |
| Full project (small cottage) | ~$100,000 – $150,000+ | Full insulated basement or difficult access can push higher |
Comprehensive projects that include a full excavated basement can run higher still. Land access (island, tight road, remote lot) and soil surprises are the biggest swing factors. To slot these figures into a whole-project budget, use our home construction estimate spreadsheet.
Risks and challenges to plan for
Movement damage
Lifting stresses the building – cracked drywall, jammed doors, stretched wiring and plumbing. Pros go slow and prep the structure; minor cracks are common and repairable.
Rain, frost, wind
An open excavation can flood, frozen ground complicates digging and curing, and a raised cottage on cribbing is exposed to wind. Timing and site protection matter.
Water and soil
Near-lake lots and high water tables mean sump pumps during the dig; loose soil needs solid cribbing pads and sometimes shoring. Boulders or bedrock can force a redesign.
Getting equipment in
Beams, jacks, and concrete trucks need clearance. Islands or tight lots may need pump trucks, cranes, or barges – which adds cost and scheduling complexity.
Coordination and cure time
Multiple crews and inspections have to line up, and concrete cannot be rushed. Expect to vacate the cottage while the foundation cures.
Cost overruns
Rotten sill beams, old asbestos, or a failed septic can appear once you are in it. Carry a contingency, and expect grandfathered “non-conforming” cottages to trigger upgrades.
Ontario code and permit considerations
This scope of work sits inside a well-defined regulatory framework. The main items your design and permit have to satisfy:
| Requirement | What it means |
|---|---|
| Building permit | Mandatory. Plans usually stamped by a Professional Engineer or BCIN designer, with inspections at footing, foundation-wall (before backfill), and completion. |
| Frost protection | Footings below the frost line (about 1.2 m / 4 ft, deeper up north) unless an engineered frost-protected shallow foundation is used. |
| Wall structure (OBC 9.15) | ICF foundation walls must be laterally supported top and bottom (Article 9.15.4.2), with rebar and thickness per the code tables; taller walls need engineered design. |
| Energy (SB-12) | The new foundation must meet minimum insulation levels; ICF usually exceeds them, and a heated slab needs under-slab insulation. |
| Radon rough-in | New residential construction requires a sub-slab depressurization rough-in so a radon fan can be added later (OBC 9.13.4). |
| Fire barrier over foam | Exposed ICF foam in a habitable or service space must be covered with a thermal barrier such as 1/2 in drywall. |
| Egress | A finished basement with sleeping rooms needs a compliant egress window; plan the window well and opening into the ICF wall. |
| Zoning + conservation | Raising the cottage can affect building height and setbacks; waterfront lots may need conservation-authority approval. |
Raising a cottage: frequently asked questions
Do I need a permit to lift a cottage and replace the foundation in Ontario?
Yes. Raising a structure and replacing a foundation is a structural alteration that requires a building permit, and most Ontario municipalities will only issue it with plans stamped by a Professional Engineer or a BCIN designer. Inspections happen at the footing, the foundation wall before backfill, and at completion. On waterfront lots the local conservation authority may also need to approve.
How much does it cost to raise a cottage and install an ICF foundation?
For a small cottage, a full project commonly lands around $100,000 to $150,000 or more. That breaks down roughly to $15,000 to $30,000 for the lift (up and down), $5,000 to $15,000 for removal and excavation, $30,000 to $60,000 for the ICF foundation, $7,000 to $15,000 for a new insulated slab, and a few thousand for permits, engineering, and utilities. A full excavated basement or a difficult, remote site pushes it higher.
Why use ICF instead of poured concrete for the new foundation?
ICF builds the insulation into the wall, so the new basement or crawlspace is warm and dry from the start – ideal when you are converting a seasonal cottage to four-season use. It costs modestly more than bare poured concrete but saves the separate insulating step and delivers a high effective R-value, which is why it is a common choice for cottage refoundations.
How deep does the new foundation have to go?
Below the frost line, which is about 1.2 m (4 ft) in most of Ontario and deeper further north, unless the design uses an engineered frost-protected shallow foundation. The exact depth for your site is set by the Ontario Building Code and your local building department, and it is deeper again if you are excavating a full basement.
Do I need radon protection in the new foundation?
Yes. New residential construction in Ontario requires a sub-slab depressurization rough-in – a perforated pipe in the sub-slab gravel connected to a capped riser – so a radon fan can be added later if testing shows high levels (OBC 9.13.4). A good builder installs it by default when pouring the new slab.
Can I leave the ICF foam exposed and finish the basement later?
Not in a habitable or service space. Exposed ICF foam must be covered with a thermal barrier such as 1/2 inch drywall for fire safety, so a basement you plan to use as living space needs the foam covered. An unfinished crawlspace used only for storage may be treated differently, but confirm with your building department.
Will lifting damage the cottage?
Some minor damage is common – hairline drywall cracks, a door that needs adjusting – because you are moving an entire building. Professional movers lift only a few inches at a time, keep the structure level across dozens of measured points, and prep fragile elements first, which keeps damage minor and repairable. This is not a DIY job; the risk of doing it wrong is catastrophic.
How long does the whole project take?
Plan for several weeks, and expect to be out of the cottage for part of it. A typical sequence is lifting in the first week, excavation and footings next, ICF walls after that, then the slab – with concrete cure time (often about 10 days for the walls before lowering) built in. Weather, inspections, and site surprises can extend it, so build in schedule slack.
Disclaimer: costs are 2026 Ontario planning ranges that vary widely by cottage, lot, access, and site conditions, and code references are general guidance, not a code interpretation. This is an engineered, professionals-only project. Confirm design, cost, and current Ontario Building Code and permit requirements with a structural engineer, licensed contractors, and your local building department.
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