A building’s foundation may be the lowest part, but it is the highest in importance when it comes to stability. A barndominium is a multipurpose building requiring a solid foundation if it is to last a long time, and choosing the best foundation is a decision you should take with patience.
You can build a barndominium on a pier and beam foundation. This foundation type provides the necessary support for the steel poles. It also allows for flexibility when constructing the barndominium on difficult soil types.
The rest of this article will explain what a pier and beam foundation is and how it works in a barndominium. After that, I will highlight some essential factors to consider when choosing a foundation for your barndominium.
How Pier Foundations Support Barndominiums
Barndominium houses take their concept from barns used to keep horses, tools, and other items, usually known as pole barns. However, barndominiums are designed to be habited by humans.
Barndominiums can be constructed with either wood or metal, but in recent years, steel has been the most common choice. Steel is what makes modern barndominiums so durable and long-lasting.
Like a barn, a barndominium has poles going into the ground that support the rest of the building. The spacing of these metal poles depends on the barndominium design.
Pier foundations are built with either brick, metal, or reinforced concrete. These foundations are great for building a barndominium, as they already work with a column beneath it.
The most common foundation used for a barndominium is a concrete slab foundation, where the poles of the barndo spring up from the slab. However, on some occasions—especially when the top soil layers aren’t firm enough—a slab foundation may not offer the stability barndominiums need.
This is where pier and beam foundations come in. Here are some of the advantages of building a barndominium with this type of foundation:
- Versatility. You can change the shape, length, and material of pier and beam foundations to better suit the soil you’re building on. This allows you to build a barndominium on any type of soil.
- Stability. The pier and beam foundation allows your barndominium to transfer the load directly to the bedrock, which is something engineers aim to do with any foundation.
- Safety. The more complex your building gets, the more critical the foundation becomes. All types of pier and beam foundations are deep enough to reach stable soil.
- Easy repairs. In a slab foundation, you have to bury all electric and plumbing pipes in the slab. The pier and beam foundations give more freedom to place these components, making them easy to fix if there are damages.
- Higher buildings. The depth of the columns and the height of the piers increases the total size of the barndominium. This will make your barndominium taller, improve its looks, and showcase its design.
Many factors come into play when choosing the right type of foundation for your barndominium. In any case, this is a decision you should leave to a professional. An engineer will know which type of foundation is best adapted to the soil type, the design, and the weight requirements of your barndominium.
How Does a Pier and Beam Foundation Work
A pier foundation is a group of columns that lift the building from the ground and leave a crawl space underneath the barndominium. This foundation type works precisely like a pile foundation—the main difference is that pile foundations work best in wet areas, while pier foundations are better for dry regions.
The columns of the pier foundation go deep into the soil until they hit firm ground. This point is usually between 1 and 1.5 feet, depending on the soil type.
The pier sits on top of these columns as beams, acting as the base for the rest of the building.
There are no identical pier foundations, as they are all unique to the site conditions. However, there are three main materials you can use to construct piers:
The soil stability and complexity of the building design will determine the right fit for your barndominium. Similarly, your pier foundation can take a cylindrical, square, or rectangular shape.
The use of pier foundations is common in areas when the good soil is obstructed by unusable top layers. Some of these cases are:
- Clay soil
- Decomposed rocks at the surface
- Sloped areas
- Low water capacity soil
There are two main types of pier foundations: concrete and drilled caisson pier foundations. Let’s take a close look at both types.
Concrete Pier Foundation
Also known as the masonry pier foundation, concrete piers are great when the good soil is not too far below—usually at a depth of 5 meters (16.4 feet).
Concrete piers are cast based on the building design. The only thing you’ll have to do on-site after you dig the holes is install the piers.
You can watch this video to learn more about it:
The cross-section of concrete piers is usually between 0.3 and 0.5 meters (12 to 20 inches), while its length can reach 20 m (66 feet). The design dimensions will depend on several factors related to the construction site:
- Needed depth to reach firm soil
- Type of topsoil
- Building specifications and load distribution.
Drilled Caisson Pier Foundation
Drilled caisson foundations have a cylindrical shape and are great for large and more complicated designs. They’re also called drilled piers, sub piers, or foundation piers.
Cassion piers are cast right on the construction site. First, the engineers will drill the hole for the pier foundation, depending on the design specifications.
The radius of the cylinder and its depth depends mainly on the soil type and building design. The drilling process is usually done with a continuous flight auger.
Here’s a video explaining the drilling process:
After the drilling process, the next step is to add reinforcements to the hole before pouring concrete.
The pier will axially distribute the load at the top of the column, and the column will partially pass the load to the soil.
There are three ways you can go about installing a drilled caisson pier foundation:
- A steel pipe reinforced with concrete drilled into the ground.
- A regular concrete column but with a broader base to provide more stability. This is the most common option.
- A drilled pier combining steel and concrete reinforcements into a steel pipe.
The choice of any of these drilled caisson types depends on:
- The soil type and depth needed to reach bedrock.
- Design specifications and the engineer’s preference.
- Your budget.
When it comes to building a barndominium or any structure, you should always prioritize safety over saving money. You can always ask the engineer why they are making any decision you don’t understand.
Barndominiums may have gotten attention because of the Fixer Upper episode, but its popularity is because of its diversity, design, and other aesthetics.
The foundation is an integral part of the barndominium, and the pier and beam foundation is a great choice. While there are many advantages to this foundation type, it has some disadvantages.
Therefore, it is better to hire a professional with experience in constructing this foundation to help with your barndominium. Additionally, ask a lot of questions about anything you do not understand.