How do you repair a pier and beam foundation? That sounds like a simple enough question, right? Well, depends on what’s wrong with it . . .
I know, I know, that sounds like the most *smart aleck-y* answer you have ever heard in your life. But there are actually a lot of different things that can go wrong with a pier and beam foundation.
Pier and beam foundations are considered to be a more “primitive” and older style of home foundation. Though in many ways, they are more complex and intricate than the newer and more modern (yet simple) slab-on-grade foundation.
Because they are a multilayered and interwoven structure, many points of contact and support are created in the making of this type of home foundation. With every point of contact and support, also comes a point of potential failure. Fascinating stuff, isn’t it?
At Anchor Foundation Repair, we have been inspecting and repairing foundations in the Brazos Valley for the past 35+ years. We have repaired our fair share of crawl space-type foundations like the pier and beam. After the slab-on-grade foundation type, the pier and beam foundations are one of the most common foundation types in this area.
In this article, we will go over how pier and beam foundations are made, how they can become damaged, and ways to repair them. By the end of this read, you will see that the pier and beam foundation type is anything but simple and primitive and have a greater understanding of what it takes to repair them.
How are Pier and Beam Foundations Made?
A pier and beam foundation is one type of crawl space foundation. Crawlspace-type foundations are typically found in older homes built before the 1950s in the Brazos Valley area but are still common in other areas of the state and country.
This foundation type is characterized by a space between the floor of the home and the ground about the size that a person could crawl through, hence the crawl space name.
Pier and beam foundations have space and air under the home, making it easier to access plumbing and electrical systems should there be a problem. This style of foundation has the potential to last a long time with good drainage and the right kind of periodic maintenance.
It’s important to have a good understanding of how this type of foundation is made in the first place to see how things can go wrong and how to get them right again.
As mentioned in the introduction, the pier and beam foundation is a multi-layered structure. So let’s start from the ground up on how these foundations are put together.
Layer 1: The Piers and the Beam
In a pier and beam foundation, it gets its name from the first parts that are in contact with the ground: the piers and the beam.
The outside perimeter of the house is supported with a “beam” or short wall of concrete blocks, bricks, or most commonly poured concrete on the outside that goes into the ground about 24” or less. This beam follows the entire outline of the home and provides continuous support along all the outside edges with a rigid material.
Underneath the interior of the home, there are stacks of concrete blocks every so often that provide support for the inside areas of the home. Each stack of blocks (called a pier) is spaced out evenly and regularly in a grid pattern.
The beam penetrates the ground around the perimeter and the stacks or piers penetrate or are stacked on the ground throughout the interior of the home, and then there is open air space in between. The next layer of the foundation is elevated above the ground on top of this array of piers and the beam.
Layer 2: The Main and Shaker Sill System
After the layout of piers and the beam on the perimeter, a formation of sill beams is laid on top for the next layer. Main sills support walls and shaker sills support the floor. These are long wooden 4” by 6” boards laid on top of the piers going straight across from one side of the home’s perimeter beam to the other. They are laid on top of the beam and then on top of the stacked piers in a straight line.
The shaker sills all go in one direction across the home and connect all the piers in a row together. They also tie the beam together with the elevated piers. This structure begins the process of distributing the home’s weight evenly across all of the connection points.
Layer 3: The Floor Joists
Floor joists lay on top of the sill boards in a perpendicular manner creating a crosshatch pattern. Floor joists are also long 2” wide pieces of wood laid vertically and they are usually spaced somewhere between 1 to 2 feet apart and vary in thickness from 6 to 12 inches.
Floor joists are put together in another weight distributing array on top of the sills. The joists are fastened to the sills and to each other to continue creating the interwoven levels of connectivity.
Joists serve as the intermediate transition piece from the heavy sill to the finish layers of flooring. They are placed closer together and allow for an installation of sub-floor next.
Every so often in between joists, there are cut-out ventilation holes to allow for airflow under the foundation. This is the main distinctive feature of a pier and beam home. Spotting these occasional ventilation holes near the ground along all sides of the home’s foundation will tell you that it is a pier and beam type foundation.
Layer 4: The Sub-Floor and Floor
On top of the floor joists, a ¾” layer of subfloor is laid down and nailed into the floor joists to create an actual flat, solid and continuous surface that someone can walk on. It’s just rough wood so it’s called the sub-floor.
The nice flooring that you actually see and walk on inside your home is layered on top of the subfloor.
The Whole Enchilada
Now that we have gone over each layer of the pier and beam foundation, you can see that it is a bit like an organized neatly layered pile of “pick-up-sticks.”
Not sure if you remember this game when you were a kid but move one stick and it can move all the other sticks because they are all stacked on top of each other.
3 Main Causes of Damage to Pier and Beam Foundations
The main enemies of crawl space foundations in our area are settlement, moisture problems, and flaws in original construction methods or materials. Let’s take a look at each of these to see how they uniquely impact pier and beam foundations.
1. Foundation Settlement due to Expansive Clay Soils
As with any foundation type, problems are caused as a result of our expansive clay soils. Expansive clay expands when wet and contracts when dry. These forces are more powerful than you think and can push around the structure of your foundation with each season and year.
As you can imagine, any push up from the ground or shrinking and sinking of soil can impact the structure of a pier and beam foundation. This constant moving from season to season can begin to cause damage to the interior of the home in the form of wall cracks, door misalignments, and other telltale signs of foundation settlement.
2. Moisture Under the Home
A pier and beam home is susceptible to moisture from poor drainage and inadequate ventilation. Excessive moisture under the home has damaging effects on all the wood, from the sill all the way up to the subfloor. Water can cause the wood materials that make up your pier and beam foundation to rot, mold, or disintegrate altogether.
Any piece of wood under your home that is compromised can cause foundation problems for you. Because of the interconnected nature of the pier and beam foundation, one piece of bad wood can have compounding negative effects on the rest of the structure.
Having an open crawl space under your home also comes with its own drainage challenges. Even though pier and beam homes have ventilation holes to increase airflow in a crawl space, they cannot allow for the removal of standing water from poor drainage.
Over time, drainage can go from effective to ineffective and can cause prolonged periods of moisture under your home that will lead to the deterioration of a crawl space.
3. Original Construction Methods or Materials
Since many pier and beam homes were constructed before the 1950s, not only were the building codes different then but also the materials used can simply become old and weakened.
One unique type of problem for a pier and beam foundation is spongy, bouncy, or wavy roller coaster floors. There are pier and beam homes that were built with the floor joists too far apart to support the weight properly. There are floor joists and shaker sills that have just broken or worn out from extended use.
Piers can break down and need to be replaced. Sometimes the piers rotate and settle differently than the ones next to them or they crack or break. There are times that the array of piers are not sufficient and more need to be added in closer spacing to support the weight of the home.
All of these situations tend to present themselves over time and can cause problems for your pier and beam foundation. But they can all be fixed as well as we will go over in the next section about repairs.
4 Ways to Fix your Pier and Beam Foundation
One of the nicer things about this type of foundation is that it’s typically less expensive to repair than a conventional slab-on-grade foundation.
Sometimes it’s easy for foundation repair contractors to access and rectify problems. If they can easily get to the parts that are failing, it’s easy to fix it for you with lesser expense than with a slab-on-grade foundation problem.
However, If it’s difficult to access the problem areas, fixing problems with pier and beam foundations can come with increased difficulty, complexity, and ultimately cost.
We will review some repair remedies in order of easiest and cheapest to most difficult/costly.
Making small but more frequent adjustments to the snugness of all your pier and beam foundation parts is what reshimming is all about. Sometimes things just get a little loose or experience a small amount of movement and this can all be fixed with simple reshimming.
This process is like preventative maintenance for a crawl space home, but it is only done if the home has been kept in good working order and has all the support material is in the proper place to support the home.
Shims are small pieces of wood that are wedged and pounded in between the piers and wooden sill beams.
Refilling gaps between the sill and settled support piers of your foundation through reshimming is a recommended maintenance task that should be done every 3-5 years. Doing this as a regular checkup kind of thing will keep your pier and beam foundation in good shape and prevent larger problems from developing.
A reshimming project on a pier and beam home would likely take about one day or less and cost between $1,200 to $1,800. A small price to pay if it means keeping larger issues from developing.
2. Rebuilding or Adding Pier Stacks
Sometimes things happen to the interior piers. The blocks can degrade or disintegrate, or there were not enough of them in the first place. A pier and beam foundation repair contractor can add more piers to more evenly support and distribute weight and smooth out bowing floors. Or simply repair/replace any that have been damaged over time.
This type of repair could take 2 days or more (depending on the size of the home and ease of crawl space access) and cost somewhere between $4,000 and $6,000 on average to bring the pier and beam foundation back into working order.
3. Replacing Wood
Shaker sills and floor joists can rot, break, warp or wear out and need to be replaced with new material. Or maybe there was not enough support built into the foundation in the first place and sills or joists need to be added. Depending on how much wood needs to be replaced and the access to get to the problem area this can be a small job or a massive overhaul and rebuilding project.
Any wood under the home that needs replacing is always a bit tricky. As we explained in the construction portion of this article, every piece of wood is connected to another piece of wood. Therefore, to remove sections of the damaged area the adjacent areas of the crawl space need to be temporarily supported to ensure the home doesn’t come crashing down.
For an extensive wood replacement job, it could take a week or more and cost $10,000 to $20,000 or more. This kind of repair project has a lot of variables and is hinged on how much wood material needs replacing and where it is located.
4. Adding Underpinning to the Beam
Many times, it’s just the interior support areas of a pier and beam home that are affected by settlement because they are in the most vulnerable area and are often underbuilt and under-supported. But the perimeter support beam can also be affected by settlement and weight distribution problems.
In a case where the perimeter beam needs to be brought back to its original elevation, drilled bell-bottom piers, or concrete pilings, must be used to add the needed support to settled areas.
Depending on the weight of the home, some foundation repair methods will work better than others for long-lasting stability. The number of supports needed as well as the repair method will affect the price. The chosen method will also affect the amount of time the project takes to complete. We have an article offering more detail about slab-on-grade foundation repair methods as well.
Should I Fix My Foundation or Do My Remodel First?
We know that many pier and beam homes are older and possibly built before 1950. It’s likely that if you live in an older home like this, you might also be thinking about remodeling or updating it in some way. As a general rule, fix your foundation first and then remodel it.
If you have any remodeling plans in your future and you know you have some foundation issues in your pier and beam home, save yourself a lot of headaches and wasted money by taking care of foundation issues first!
If you remodel before correcting foundation issues, you run the risk of damaging brand new finishes, paint jobs, and flooring materials if your house continues to settle and become unstable after remodeling. Don’t risk wasting your hard-earned remodel dollars.
Many times, we find ourselves working on a pier and beam foundation for the very reason that the owner wants to finally begin that remodel. Be sure to include any needed foundation work in your remodeling budget.
Is What You Are Seeing Around Your Home a True Foundation-Related Problem?
Now that you know how many different things can go wrong with your pier and beam foundation, you probably want to make sure that what you are seeing around your home is truly an issue from settlement or deterioration of your crawl space and not some other type of “older home” problem.
After 35+ years in the business of foundation repair in the Brazos Valley, we have been asked about every home symptom under the sun. After inspecting tens of thousands of homes in the area, we can tell if signs are foundation-related or something else.
All foundation types display similar signs if foundation settlement is the culprit. There are also home symptoms we commonly get asked about that don’t end up being foundation-related. Check out this picture guide and article on real and false signs to be doubly sure you’ve got an issue.