Have you ever seen a house that looks like it is sitting on stilts? Or maybe you’ve seen some videos of workers crawling through tiny spaces under a home. These homes have pier foundations. Find out what a pier foundation (also known as a pier and beam foundation) is, the different types, the pros and cons of piered foundations, and common maintenance and repairs.
Note: Piers can also be added to any type of foundation after construction to ensure stability. These types of piers are different from the piers used to construct pier foundations. So, if you hear the term “piered foundation”, keep in mind that this might refer to a pier and beam foundation or it might refer to the piers used to repair and stabilize any type of foundation.
How Do You Define a Pier Foundation?
A pier foundation, also known as a pier and beam, a post-and-pier, or a post foundation, is any foundation that uses vertical columns (pilings or posts) as supports for the structure. The columns are driven into the ground and attached to horizontal beams or joists, forming a grid-like network evenly distributing the structure’s weight across the soil.
Piered foundations are commonly used in unstable soil conditions, where other types of foundations may not be suitable. They are also preferred in coastal regions, areas prone to flooding, or places with high water tables, as the elevated structure protects against water damage.
What Are the Different Types of Pier Foundations?
There are several different types of pier foundations, each suited to specific site conditions and construction requirements. Here are some common types:
- Concrete Piers – These are cylindrical or square-shaped concrete columns cast in place or precast and then installed into pre-dug holes in the ground. Concrete piers offer excellent load-bearing capacity and durability, making them suitable for supporting heavy structures.
- Steel Piers – Steel piers, also known as steel posts or piles, are columns driven into the ground to support the structure. They are often used in corrosive soil conditions or where additional strength is required.
- Timber Piers – Timber piers, made of treated wood, are driven or installed into the ground to support lightweight structures such as decks, porches, or small cabins. They are inexpensive and easy to install, but may not be as durable as concrete or steel piers, especially in wet or corrosive environments.
- Drilled Piers (Caissons) – Drilled piers, also known as caissons or drilled shafts, are constructed by drilling cylindrical holes into the ground and then filling them with concrete. They are often used in large-scale construction projects requiring deeper foundations to reach stable soil or bedrock layers.
- Masonry Piers – Masonry piers are hand-built piers made of concrete blocks, bricks, or flat, large stones and are commonly used for homes that do not require a deep foundation. Of the three types of masonry piers, concrete blocks are the most durable. In contrast, brick and stone piers have become outdated and are typically used to maintain the uniform appearance and charm of older homes.
Is a Crawl Space Considered a Pier Foundation?
Yes, a crawl space is an enclosed pier foundation that raises the building anywhere from 18 inches to three feet off the ground. A crawl space uses wooden, steel, concrete, or masonry piers to raise the home and a grid of wooden beams and joists to create the subfloor. Crawl spaces are common in the Southeastern United States, particularly amongst homes built before the 1970s, due to their versatility in design options and ability to protect the house from flooding.
What Are the Pros and Cons of a Piered Foundation?
Pier foundations offer several advantages, making them popular in various construction scenarios. Some of the pros of pier foundations include:
- Adaptability to Site Conditions – Pier foundations can accommodate various soil conditions and uneven terrain. The height of the piers can be adjusted to compensate for sloping ground, minimizing the need for extensive excavation or grading work. Adding an addition to your home is relatively easy because you only need to add a few more piers.
- Flood Resistance – Elevating your home can protect against flooding by keeping the living space above the potential water level.
- Cost-Effectiveness – Pier foundations are often more cost-effective than traditional deep foundations, like basements, especially in areas with shallow bedrock or stable soil close to the surface. They require less material and labor for installation, making them quicker to install and reducing construction costs.
- Accessibility to Utilities – The raised foundation provides easy access for maintenance and repairs to utilities such as plumbing, electrical wiring, and HVAC systems. This accessibility can save time and money on maintenance over the structure’s life.
While pier foundations offer several advantages, they also have some potential drawbacks. Here are some cons of pier foundations to consider:
- Maintenance – Pier foundations can expose your subfloor to the environment, leading to sagging floors, mold, rot, and other deterioration. The piers themselves can also deteriorate over time. Hence, maintenance is required to prevent deterioration from moisture, pests, or other environmental factors. Inspections and repairs may also be necessary over time.
- Vulnerability to Shifting Soil – In areas with expansive or unstable soil conditions, pier foundations may be susceptible to movement or settlement, leading to structural issues such as uneven floors or cracked walls.
- Pest Control – Elevated structures with crawl spaces may be more prone to pest infestations, such as rodents or insects, which can find their way into the crawl space and potentially cause damage to the structure.
- Subject to Tilting – Piers are subject to cracking, tilting, and collapsing. With one damaged pier, you may notice a significant floor section is sagging, and your home’s framing can warp. However, if multiple piers are damaged simultaneously, it can cause foundation failure.
How Do You Maintain a Pier Foundation?
Keeping water away from your foundation is pivotal to maximizing its longevity. Consider the following suggestions:
- Regrade Your Yard – Ensure the soil near your foundation slopes away from your home so that water does not pool under your foundation.
- Keep Gutters Clean – Removing debris from your gutters ensures that water does not spill over the sides, oversaturing the soil.
- Install Downspout Extensions – These make your gutters more efficient by carrying water safely from your foundation.
- Install a Drainage System – Systems like drain tile and French drains can remove excess water from the soil and divert it to a sump pump, which will actively push water away from your foundation.
- Crawl Space Encapsulation – Encapsulating your crawl space will make it completely waterproof and prevent issues like mold, rot, and pest infestations.
- Regular Inspections – Consider getting an annual or biannual foundation inspection to catch any issues early, preventing expensive repairs.
For more information, see An Overview of Foundation Damage and How to Fix It.
Common Repairs for Pier Foundations
Most pier foundations – like any foundation – will eventually need some repairs. Standard repair options include:
- Fix Damaged Piers – If your pier is slightly tilted, it may only need a shim to stabilize it. If the mortar wears out on your brick or stone pier, it may need fresh mortar.
- Replace Damaged Piers – A damaged pier must be replaced in most cases. If the pier is challenging to remove, a new one can be constructed close to the failing pier to support that portion of the subfloor.
- Add Extra Piers – If the original foundation lacked sufficient piers to support the structure, more can be added.
- Foundation Underpinning – In some cases, push or helical piers can be installed to support sinking or settling pier and beam foundations by connecting the structure to stable strata and lifting it back up to the maximum practical level.
If you suspect your piered foundation needs repair, schedule a free inspection and foundation repair quote today. We serve North Carolina, including Raleigh, Durham, Greenville, and the surrounding areas.
