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Different Types of Foundations in Ontario Residential Construction

  • Yousef Davari
  • Jul 23
  • 3 min read

Updated: Dec 13

Selecting the right building foundation is one of the most important decisions in Ontario residential construction. Climate conditions, soil variability, frost depth, and OBC 2024 requirements all directly influence how different foundation types perform over time.


This overview explains the most common foundation types used in Ontario homes, their typical applications, and key considerations engineers evaluate before construction begins.



ICF Foundation Walls During Concrete Pouring in Ontario
© Photo by Sery

A slab-on-grade foundation consists of a reinforced concrete slab placed directly on prepared soil.


Common uses

  • Garages and sunrooms

  • Small additions

  • Low-rise residential structures


Why it works

  • Minimal excavation

  • Faster construction timeline

  • Cost-effective when soils are stable


Key considerations

  • Utilities are embedded below the slab

  • Limited adaptability on sloped sites

  • Requires proper insulation and vapor barriers to meet OBC Part 9


Slab-on-grade is a practical type foundation when no below-grade space is required and soil conditions are suitable.


2. Full Basement Foundations


Reinforced Concrete Footings Prepared for House Foundation
© Photo by Concrete Forms

Full basements remain the most common building foundation choice in Ontario residential projects.


Typical construction

  • Full excavation to frost depth

  • Reinforced concrete footings and walls

  • Drainage systems and waterproofing

  • Interior basement floor slab


Advantages

  • Additional usable living or storage space

  • Easier routing for mechanical systems

  • Strong resistance to frost and soil pressure


Limitations

  • Higher construction cost

  • Sensitive to groundwater without proper waterproofing


When designed correctly, basement foundations offer excellent durability in Ontario’s climate.



Crawl spaces elevate the structure slightly above grade, creating a shallow accessible area below the floor.


Strengths

  • Access to plumbing and HVAC systems

  • Reduced excavation compared to basements

  • Adaptable for moderate site conditions


Challenges

  • Moisture control is critical

  • Requires proper ventilation and insulation


Crawl spaces serve as a balanced option between slab-on-grade and full basements.


4. Pier and Beam Foundations


Pier and beam systems support structures using discrete load-bearing elements rather than continuous walls.


Common options

  • Helical piles

  • Sonotube concrete piers

  • Enlarged base footings (e.g., Bigfoot systems)


Benefits

  • Effective on sloped or weak soils

  • Reduced excavation

  • Fast installation with helical piles


Drawbacks

  • Specialized installation requirements

  • Weather sensitivity for cast-in-place systems


These foundation types are often used for decks, additions, and challenging site conditions.


5. Insulated Concrete Form (ICF) Foundations


ICF foundations combine reinforced concrete with permanent insulation forms.


Advantages

  • High energy efficiency

  • Strong moisture resistance

  • Excellent structural performance


Considerations

  • Higher upfront cost

  • Requires experienced installers

  • Must meet specific OBC reinforcement and insulation criteria


ICF systems are well-suited for high-performance residential buildings.


How Engineers Select the Right Foundation


Structural engineers evaluate:


Proper engineering ensures the selected building foundation performs reliably over the long term.


Conclusion


Ontario residential construction offers several proven foundation types, each with distinct strengths and limitations. Slab-on-grade, crawl spaces, basements, pier and beam systems, and ICF foundations can all meet code requirements when properly designed.


At Parsways Inc., our engineers provide code-compliant foundation design tailored to Ontario’s soil conditions and climate—helping homeowners and builders select safe, durable solutions with confidence.


Co-authored by Yousef Davari and Negin Amani.



FAQs


What is the most common building foundation in Ontario?

Full basement foundations are the most widely used due to frost resistance and added living space.

Can different foundation types meet Ontario Building Code requirements?

Yes. Multiple foundation systems are permitted when designed in accordance with OBC 2024.

When should a structural engineer be involved in foundation selection?

Before construction begins, especially when soil, groundwater, or site conditions are uncertain.







 
 
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