Buildings are more than simply four walls and a roof. There’s a whole science behind architecture and ensuring that the elements that we can see remain standing strong. Like icebergs, buildings stretch downwards as well as up. Foundations and footings allow everything from a small home to a mighty skyscraper to exist, but what is the difference? When are we speaking about footing vs foundation?
Footing vs Foundation
While both structures have the purpose of enhancing the structural stability of the building above by distributing weight, they’re not interchangeable terms.
What is a foundation?
A foundation is the base of a structure which distributes the weight of everything above it to the ground. Without these, walls would fall over and slabs sink. They come in a few different varieties:
- Slab-on-Grade: A solid concrete ‘pillow’ placed on graded soil.
- Deep foundations: An excavated area which allows the walls to be pushed into place by the surrounding soil. These are often turned into crawlspaces and basements.
They could be built from various materials including concrete, stone or brick. Whichever type is employed in your building, it’s vital that they’re properly and appropriately waterproofed to avoid structural damage occurring over time.
What is a Footing?
A footing is a concrete base which supports the foundation. Just like a foundation spreads the weight of the building above, a footing does the same thing for the foundation.
They’re generally made of reinforced concrete and employed with particularly heavy buildings or in softer-soiled areas. They generally work by either resting against the solid bedrock or simply spreading the weight over a greater area, reducing the PSI (Pound-force per square inch). This helps reduce issues like settlement and shifting.
Footing vs Foundation: Key Differences
While they’re both important contributors to structural stability, they each do a different job and work in different ways.
Purpose
Foundations support the entire building, transferring the weight to the footing. The footing supports the foundation and ensures that weight is evenly spread to the ground under the building.
Placement
Footings are placed directly against the soil (or, in some cases, the bedrock), below the frost line. Foundations rest on top of the footings.
Materials
Generally, footings are constructed of reinforced concrete (though other things might be used, especially in older buildings). Foundations however can be made from all kinds of materials, most commonly poured concrete, brick, stone or breezeblocks.
Role in Structural Integrity
The job of your footings is to ensure that your building doesn’t sink or settle unevenly, causing cracks and damage. Foundations ensure that the building is stable and aligned properly, holding up the walls above.
Relationship Between Footings and Foundations
While we might have phrased the title of this article as ‘footing vs foundation’, they actually work in concert rather than opposition. Both footings and foundations are vital components of any build, ensuring structural stability of the final building.
This symbiotic relationship starts with laying the footings. These come in a few different designs including:
- Spread Footings: These are large, typically square or rectangular, reinforced concrete slabs designed to distribute the weight of a structure over a wider area of soil. The “spread” increases the surface area, reducing the load per square foot and preventing soil settlement. Spread footings are commonly used for buildings with moderate loads or where soil conditions allow for shallow foundations.
- Strip Footings: Long and narrow footings that run continuously beneath load-bearing walls or rows of columns. Strip footings distribute the load along their length and can be placed at varying depths based on the weight they need to support. They are commonly used in masonry or brick construction and are ideal for uniform loads along a wall.
- Pile Footings: These consist of long, slender concrete or steel columns driven deep into the ground to provide support in unstable soil. Piles transfer the building’s load to firmer soil layers or bedrock, making them ideal for areas with loose or shifting ground conditions.
- Mat Footings (Raft Foundations): A large, continuous slab of reinforced concrete that spans the entire footprint of a building. Mat footings evenly distribute the structure’s load over a broad area, making them suitable for heavy buildings or weak soil. They also allow for shallow excavation, which can save time and costs in certain projects.
Whichever is used in your particular design, these concrete footings all share the same basic purpose: supporting the foundations. In turn, the foundations ensure that everything above them is properly aligned and supported. Together footings and foundations ensure structural integrity and keep your building standing.
Waterproofing
Regular readers will know that we worry about water an awful lot. When water gets where it shouldn’t, even the strongest constructions can get into trouble. Badly laid footings or ill-constructed foundations can often suffer from water intrusion, allowing a point of access to the rest of the home.
Without careful consideration of water management, the work of the concrete footings and foundations can be undermined. Water will eventually erode concrete and find a way through blockwork if you let it. Even if it doesn’t, pooling water will soften the surface on which your home stands, leading to subsidence.
Installing membranes and French drains around foundations and footings can go a long way towards preventing these issues.
Why Proper Installation is critical
When building anything, it’s vital to take a proper look at the local conditions. Methods and techniques which might be suitable for one project might not be for the next. Different types of soil and different loads will require different designs of footings and foundations.
As a general rule, softer soils and bigger builds will require deeper excavations for the footings. Designs like mat footings may be an option where this isn’t possible but it’s always best to undertake thorough examinations before breaking ground.
Where these considerations aren’t properly addressed problems will arise: sinking, cracking, water infiltration or even structural collapse.
It’s vital to always work with a professional team when building to ensure that local codes are met, and long-term performance is at the forefront. This is true whenever you’re building anything.
Common Problems and How to Address Them
Even well-constructed foundations and footings can experience problems. Luckily, many of them can be rectified through remedial work or retrofitting solutions. When considering footing vs foundation issues, identifying the root cause is essential for choosing the right repair method.
Footing Problems
Problems with footings are most often caused through poor drainage or faulty initial designs. Generally, remedial work can be undertaken but be warned- it can be a serious undertaking in terms of excavation.
The most common problems include:
- Settlement caused by poor soil conditions or the incorrect size being laid in the first place.
- Erosion from water exposure. This could be erosion of the soil or the concrete of the footings themselves.
Foundation Problems
Foundations and the crawlspaces and basements we make out of them can face a wide array of issues, especially around water ingress. Repair work can range from the very simple to a complete overhaul of the waterproofing systems, depending on exactly the issues you’re facing.
Common problems include:
- Cracks forming thanks to settlement, shifting and water pressure pushing against the walls
- Bowing walls or uneven settlement where one side of the building sinks further than the others.
Solutions
Addressing problems with footings and foundations requires a tailored approach based on the root cause, severity, budget, and site-specific factors. Here’s how these issues are typically resolved:
Erosion and Water Intrusion
Managing water flow and preventing further erosion are critical first steps. Solutions can range from minor repairs to major excavation projects:
- Minor Repairs: Filling cracks, applying sealants, or installing internal measures like sump pumps and French drains to manage water buildup effectively.
- Major Groundwork: Excavating around footings to address erosion directly. This presents an opportunity to upgrade other waterproofing systems, such as exterior membranes or drainage tiles, ensuring comprehensive protection against future water issues.
Structural Damage
For structural issues like cracks, bowing walls, or uneven settlement, reinforcement techniques are key:
- Carbon Fiber Reinforcement: Adding carbon fiber strips or laminates strengthens walls without invasive procedures, ideal for less severe damage.
- Steel Reinforcements: Installing steel I-beams helps redistribute pressure and provides added support for walls under stress.
Severe Structural Instability
In cases where stability is significantly compromised, more advanced interventions may be required:
- Wall Anchors: These systems extend through walls into surrounding soil to pull the wall back into proper alignment, effectively addressing bowing or leaning walls.
- Underpinning: Extending the foundation deeper into stable soil layers helps distribute the building’s weight more evenly, addressing severe settlement issues.
Proactive Action
It’s crucial to remember that issues with footings, foundations, and basements worsen over time. Early intervention minimizes damage, reduces repair costs, and ensures the long-term safety of your structure. Acting promptly can save both time and money while preventing small problems from escalating into major structural failures.
Footings, Foundations and Basement Waterproofing
You may have noticed that some of those techniques in the last section are remarkably similar to basement waterproofing techniques. That’s no coincidence, water and its management is often the best way to keep your home stable.
Your foundation wall is the first line of defense against water finding its way in, but it almost always needs help. Pairing your concrete foundation footings with measures like French drains, sump pumps and other tools for controlling water flow significantly boosts their effectiveness. Not only will this keep your basement nice and dry, it serves to keep the building stable in the long-term.
Problems which start in the foundations generally don’t stay confined down there. Water ingress can lead to mold, structural damage and other serious issues. Bringing in the professionals at the first sign of trouble can save you a fortune in the long-run, saving you money and, potentially, saving your home.