The Ultimate Guide on How to Fix A Retaining Wall
A retaining wall isn’t just an aesthetic element in your yard. It has a job to do, holding soil — and whatever’s in and on that soil — in a certain position.
Here in the Franklin area, without retaining walls, large areas of our yards might be unusable due to the rolling hills.
But sometimes retaining walls weaken for one reason or another. When they do, you need to know how to fix a retaining wall before the wall fails completely.
Let’s explore the common causes of failure and how to fix a retaining wall so that it can continue to do its job for years to come.
Retaining Wall Basics
A retaining wall may be used to:
- Prevent erosion
- Increase usable space by reducing slope
- Prevent sink holes from soil shifting
- Avoid flooding by redirecting water
- Enhance landscaping
When you see a retaining wall, you may think that it’s just a pile of bricks and mortar. But in order to withstand the pressure behind the wall, it must contain a system of supports to keep the wall from toppling over.
A retaining wall that is more than 12 inches tall should have, at the very least:
- Batter – A lean/slant toward the dirt that it’s holding back
- Tie backs (anchors) that use the weight of the soil behind to support the wall
- Drains behind the wall that redirect water from behind the wall
- Filter fabric
- A bed of gravel under the wall to give the wall room to expand/shift with becoming unstable
- Footing (portion of wall that is under the ground)
- A wall
What Causes Retaining Wall Damage
There are several causes for retaining wall damage. Some are more preventable than others. Your wall could have:
- Grown weaker with age. Depending on the design, a wall should last 50+ years.
- Clogged drains that allow water to build up behind the wall
- Not been installed with proper supports
- Been installed on an improper foundation
- Roots invading the wall
- Unexpected load demanded of the wall (eg, shed instead of flower bed)
- Been involved in a natural disaster like the 2010 Franklin & Middle TN flood
- Suffered from foundation issues
How To Prevent Retaining Wall Damage
To prevent retaining wall damage, you should first make sure it’s installed correctly in the first place. But beyond that, when the wall begins to fail, it’s important to know how to fix a retaining wall and to address it quickly to avoid more severe damage.
Fixing the Mortar
In a brick and mortar retaining wall, the bricks are secured together with a layer of mortar, which looks like a light gray concrete.
This mortar is typically one of the first things to show wear on a well-made wall.
- Carefully chisel out mortar to a point of a little over 1/2 the depth of the brick.
- Replace the mortar
- Clean up the exterior
- Let it set
Repeat this process anywhere that mortar is chipping away.
Fixing Cracked Bricks
Even one cracked brick on your retaining wall can appear unsightly. On top of this, a crack never stops with one brick.
If there were a crack in the Hoover Dam, it might start small. But the engineers would never delay fixing it because they know of the force behind that dam.
Your wall is much the same. A broken brick would spread as the force of the wall’s weight has to be redistributed to the other bricks. The integrity of the wall would fail.
But repairing the brick or bricks can help redistribute the weight appropriately to prevent further failure.
Here’s how to fix a retaining wall cracked brick.
- Chisel out the mortar around the brick
- Remove the brick
- Reapply mortar under where the brick will be placed
- Reapply mortar around the brick
- Clean up the exterior
- Let it set
This will likely work if you have 1-2 bricks that have cracked. If multiple bricks crack or the wall is bowing or leaning, you have a much bigger problem on your hands.
But no worries. We’ll talk about how to fix a retaining wall in these instances as well.
Fixing a Leaning or Bowing Retaining Wall
If the wall if under 1-2 feet tall, you may decide to disassemble and reassemble the wall. As you do so, you should evaluate the drainage system and any other issues that led to failure.
In these cases, you can do it yourself, but to do it right a structural engineer should have a look at the wall so that you have a clear understanding of what’s impacting the wall.
If the wall is higher than 1-2 feet, then hiring a structural engineer to inspect the wall is essential. Once a professional determines the cause for the leaning or bowing, the issue can be resolved — often without completely demolishing the wall.
If drainage is inadequate then water will build up behind the wall. A better drainage system may need to be added. A professional might also recommend re-grading to redirect water around the wall rather than it trying to go through it.
Your retaining wall was built with a flower bed in mind. But then you decided to build a pool house. Oops.
The wall will need to be reinforced to support this added weight — preferably before you build this pool house.
A structural engineer may recommend increasing the footing (the wall that is underground) to improve the wall’s ability to transfer weight down instead of out. The footing could be extended or reinforced with concrete.
If a tree is extending its root system into your wall, then the best thing to do is have the tree removed and then repair the wall damage.
Poorly Anchored or Failing Wall
If the wall was not properly anchored, a professional will need to excavate the soil and rock behind the wall and use one of several anchoring methods to stabilize the wall.
How to Fix a Retaining Wall the Right Way
When fixing a retaining wall, some repairs are small. Others require that a professional determine what’s causing the failure so that it can be properly addressed.
For an expert opinion on how to properly repair your wall, contact us today.