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Code & PermitsDo You Need an Engineer for ICF?
Do You Need an Engineer for ICF?
When the Code Tables Are Enough, and When They Are Not
Some people will tell you every ICF wall in Ontario needs a stamped engineer. Others say you never do. Both are wrong. Here is how it actually works under the 2024 Ontario Building Code, and how to avoid paying for engineering twice.
The Short Answer
Under the 2024 Ontario Building Code, flat ICF foundation walls can be designed from the prescriptive tables in Part 9 (Tables 9.15.4.5.A, B and C) within their limits on height, backfill and openings. Above-grade ICF walls in houses are commonly designed using the ICF industry’s Canadian Part 9 engineering tables, which cover buildings up to one storey below and two above grade with limits on size, spans and wall heights. Outside those limits, or when your building department asks, you need a Professional Engineer. Structural engineering for a typical custom ICF home costs about $1,500 to $3,500.
The Code Tables for ICF Foundations
Part 9 of the Ontario Building Code covers houses and small buildings. Since the code was harmonised with the national code, it includes prescriptive tables for flat insulating concrete form foundation walls. They set the minimum core thickness and reinforcement based on things like wall height, height of backfill and soil.
If your foundation fits the tables, a qualified designer can show it on the drawings without a separate structural engineer. Many basements fit. Walkouts with big openings, very deep basements, high backfill, poor soils and retaining conditions often do not.
Above-Grade ICF Walls
The ICF manufacturers publish a Canadian engineering manual for ICF walls in Part 9 houses. It works like a set of pre-engineered tables. Within its limits it tells you the core size, steel and lintel details for above- and below-grade walls. Its scope is roughly:
- Residential buildings under Part 9.
- One storey below grade and up to two storeys above.
- A footprint up to about 300 square metres (3,200 sq ft) and a maximum length of about 24 m (80 ft).
- Floor spans up to about 7.3 m (24 ft) and roof spans up to about 12.2 m (40 ft).
- Main floor walls up to about 4.9 m (16 ft) tall and second-floor walls up to about 3 m (10 ft).
- Only for forms from member manufacturers, and only for the seismic values it lists.
Floors, roofs and their connections to the walls are not covered and are designed by others. Some Ontario building departments accept table-based designs readily; others ask for an engineer’s stamp anyway. Ask yours early.
Not Sure If Your Design Fits the Tables?
Send us the plans. We will tell you whether it is a table job or an engineered job before you pay anyone.
When You Definitely Need an Engineer
Outside Part 9
Bigger buildings, more than three storeys, commercial and most multi-unit work.
Outside the tables
Tall walls, long spans, big window walls, cantilevers, point loads from beams.
Retaining and special
Retaining walls, pools, deep walkouts, walls holding back soil on one side only.
Concrete floors and roofs
ICF floor decks, concrete roofs and anything heavy hanging off the walls.
Who Does What on the Drawings
The designer (a BCIN-qualified designer, architect or engineer) prepares the drawings. The structural engineer, if needed, designs the walls, lintels, steel and connections and stamps those sheets. The heat loss and ventilation designs come from a qualified designer too. Our sister site OntarioHeatLoss.ca handles that part. The ICF permit guide has the full list.
What Engineering Costs
| Scope | Typical 2026 range |
|---|---|
| Garage or simple outbuilding | $1,500–$4,000 |
| Custom ICF home, structural | $1,500–$3,500 |
| Complex home with walkout, big openings | $3,000–$6,000 |
| Pool or retaining wall | $1,500–$4,000 |
| Site review visits during construction | $300–$800 each |
How Not to Pay for It Twice
- Pick the ICF brand before the engineer designs, so details match the forms you will use.
- Lock window and door sizes first. Moving openings means redoing lintels.
- Use metric rebar designations (10M, 15M, 20M). US drawings with #4 bars cause delays.
- Send the engineer your geotechnical report if you have one.
- Bring your ICF crew into the conversation before the drawings are final.
Get a Real Number for Your Project
Send us your plans or a rough sketch. We price the ICF work from real wall areas, not guesses, and tell you straight if ICF is not the right fit.
Questions We Get
Does every ICF house in Ontario need an engineer?+
No. Flat ICF foundation walls that fit the Part 9 tables can be designed without a separate engineer, and many above-grade ICF walls can be designed from the industry’s Part 9 engineering tables. Anything outside those limits needs a Professional Engineer, and some building departments ask for one regardless.
What are the OBC tables for ICF foundations?+
Part 9 of the 2024 Ontario Building Code includes prescriptive tables for flat insulating concrete form foundation walls, Tables 9.15.4.5.A, B and C, which set minimum thickness and reinforcement by wall height and backfill.
How much does an engineer cost for an ICF house?+
Typically $1,500 to $3,500 for the structural design of a custom ICF home, more for complex designs with walkouts and large openings.
Can my house designer design the ICF walls?+
A qualified designer can use the code tables and the industry tables within their limits. Outside those limits, the walls must be designed by a Professional Engineer.