House Foundations

Basement: Full and Daylight

A full basement has structural foundation walls that are supported by foundation footings. In modern homes, they are made with poured concrete or mortared concreate block. Footings extend below the frost line. If desired, it can be heated or cooled like the rest of the house. A full basement can act as a living space with a height that is at least 6ft tall [1]. A daylight basement is when the foundation is built against a slope and it has one or more sides that are completely embedded in the ground from floor to ceiling. As the slope descends, certain sides of the foundation are exposed to light allowing large windows and doors to bring daylight in [1]. Modern basements are made with poured concrete or mortared concrete block whereas basements located in old homes can have stone walls [1].

Pros

• • Space for storage and additional living space [3]
  • Natural ventilation

Cons

• • Expensive [3]
  • Lead to more maintenance issues if not properly cared for as basements are known for having issues relating to flooding, moisture, and mold

Crawlspace

A crawlspace has foundation walls that stand on footings. The walls are short (can be 4ft tall for storage) creating a space where you must crawl to get through. These spaces are unheated but can be ventilates to allow a small amount of airflow. It is less expensive than full basements because they require less excavation, foundation wall material, and labour to build. Typically, crawlspaces are made with poured concrete or mortared concrete block [1].

Pros

• • One of the most durable foundations in areas with a high groundwater level [3]
  • Better airflow underneath the house in the hot months
  • Storage for outdoor items

Cons

• • More difficult to heat the home in the winter due to the open space below the house [3]
  • Stagnant water and moisture can become trapped in a crawl space and cause health issues
  • If not insulated and sealed properly, issues will occur

Pier Foundation

Similar to crawlspaces, “pier foundations are constructed using small circular or square pads of concrete that are located in strategic points along the outer perimeter of the home. These pads are inserted and secured into the ground using treated wood posts or steel rods. These posts or rods are then connected to the home for support.” [3].

Pros

• • Ideal for plots of land where traditional foundation is difficult to lay [3]
  • Strong and durable
  • Excellent support and doesn’t come with the cons that full basements and crawlspaces have

Cons

• • Expensive [3]
  • Foundation can lead to creaking and sagging floors
  • Associated with poor ventilation

Concrete Slab-On-Grade

This type of foundation is used in climates that do no experience freezing and thawing (otherwise it would lead to cracks in the concrete and shifting of the foundation). It is a solid piece of concrete that rests on the ground. Grade refers to the ground-level and slab refers to the monolithic concrete pad [1]. The thickness of a slab can range from 4 inches – 8 inches and are reinforced with steel rods and drainage pipes [3].

Pros

• • Offers better protection against termite infestation (more common in warmer climates) since there is no airspace in between the home and the foundation [1]
  • Less expensive than a full basement and crawlspace [1]

Cons

• • More susceptible to warming due to a lack of ventilation between the home and the slab [1]
  • Little protection against floodwater [1]
  • Offers no storage or living space [3]
  • Concrete slab must be cut into to access the pipes [3]

Additional Reading

Deep Foundations

Foundation Building Code

Shallow Foundations

Underpinning

References

Contributors