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Why Do Retaining Walls Fail?

Nov 11

Retaining walls are an important part of many different landscaping jobs for a variety of reasons. The main purpose of a retaining wall is to restrain soil so that it can maintain a position, slant, or level that it normally wouldn’t be able to. 
 
Retaining walls are man-made structures that are designed in a few different ways depending on the demands of the job. Regardless of which type of retaining wall you have, either gravity or cantilever, it’s really important that these walls maintain their integrity and don’t fail over time. 
 
Especially in times of bad weather or other disturbances, it does happen that retaining walls may fail. This can cause a big problem for any space, regardless of it being residential, commercial, or industrial. 
 
In this article we’re going to take a look at the common reasons that retaining walls fail and some tips that can be used in order to recover the wall and rescue it from complete destruction. 

Main Causes of Retaining Wall Failure 

When a retaining wall is failing, you can visually see that there is something wrong through a few common signs, which include tilting out of vertical composition as well as cracking. Even the best retaining walls can fail, and some of the main reasons that this happens includes foundation issues, soil expansion, wall overload, construction mistakes, design errors, ineffective drainage installation behind the wall (missing or clogged weep holes), or reinforcement deficiency.

As you can see, there are quite a few reasons why retaining walls can fail, which means it’s important for the installation of retaining walls to be executed with a high level of success to prevent any controllable factors from causing issues. 

What Type of Retaining Walls Fail? 

While there are a variety of ways a retaining wall can be constructed, if the wall is constructed with certain materials or shortcomings, it won’t be able to stand the test of time. 
 
Here, we examine what types of retaining walls are likely to fail. 

Block Walls without Adequate Reinforcement 

It’s important that you have a licensed professional install your Kelowna retaining walls, as this can be a make-or-break element to whether or not your retaining wall will stay standing. 
 
The most common type of retaining wall failure involves a block masonry wall; while this is a common type of wall for foundation, it’s also one that is commonly installed by untrained or uncertified contractors, which can lead to a lack of expertise in its engineering. 
 
If the design is not properly executed, the wall will typically follow the process of eventual demise— tilting forward, cracking, and collapse. This process can be exacerbated by bad weather or natural disturbances that increase the rate of destruction; the wall cannot withstand these added pressures, and therefore fails. 
 
When there is no reinforcement on a block wall, the height of the wall will be limited to under four feet; anything above that won’t be able to stand the test of time. This is clearly a rookie mistake that no licensed professional should make, and a huge design flaw that is unacceptable. 
 
Moreover, if there is reinforcement that is inadequate, such as concrete filling with steel reinforcement, it won’t hold unless it is securely anchored at the sufficient depth for security. Even with these measures taken, the wall still isn’t likely to withstand anything over 4 feet. 
 
There must be enough footing to hold the wall and reinforce its presence through the foundation.

Retaining Walls Lacking Proper Drainage

On a retaining wall, there must be effective escapes for water so that moisture doesn’t build up behind the wall and damage its integrity. When water builds up behind the wall, there is a lot of increased pressure on the wall. 
 
The problem is that even if a retaining wall does have weep holes, which are the method of retaining wall drainage, in place, they are often clogged. This is an easier fix than some of the other drainage issues, which include having weep holes that are not in the right spot, as well as weep holes that are too small. 
 
When Kelowna retaining walls don’t have the proper weep hole drainage in place, rainfall can be a main trigger for retaining wall failure. After the fact, there is not much that can be done, but it’s much better if the wall has a backfill of sand or gravel, with a foundation drain, weep holes that are placed correctly and of the right size, and not clogged. 

Can I Save a Retaining Wall? 

When Kelowna retaining walls fail, it’s a huge stressor, and can cause devastating problems for your residence or commercial property. While the word “fail” can mean different things depending on what the issue is, if you can catch your retaining wall failure at the beginning times, you may be in luck. 
 
Let’s take a look at the different occasions where you may need to save a retaining wall, and whether or not it would be feasible. 

Reinforcement Issues 

If the main problem with the retaining wall is due to reinforcement, there will be signs of cracking and deflection, which means that the concrete or building material is no longer level but is giving out. 
 
When this happens, you’ll need to call in a local retaining wall professional to take a look at the size, depth, and spacing of the reinforcement. It is only after the current state of the retaining wall is determined that a solution can be identified and executed. 
 
Extending the footing of the wall or using a tie-back can both be viable solutions for reinforcement issues depending on the state of your wall. 

Drainage Issues 

There are two main drainage issues that you may encounter in a retaining wall, which include weep holes that aren’t effective, or backfill that has become sodden. Both of these are issues that need to be resolved if you want to save your retaining wall. 
 
When you have soddened backfill, you’ll need to have your backfill altered to be at a slant or grade, which allows the water to be channeled away from the wall. It’s important to make sure that the backfill material is also of high quality and that the drainage channels are effective in disposing of unwanted water. 
 
Removing and replacing backfill can typically help in resolving this issue and is often necessary if the backfill is already soaked. 
 
If your weep holes aren’t effective or are clogged up, you’ll need to ensure that there is a filter to guide water through the weep holes. The measurements of the weep holes are also important for Kelowna retaining walls, so having a professional determine what is necessary in terms of size and filtering. 
 
Unfortunately, these types of adjustments can be very costly, so other options like grading the wall, minimizing your irrigation use, or coring weep holes through the wall can help. Discuss options with your local Kelowna retaining wall builder.

Bad Design 

Unfortunately, if your designer was less experienced than you were led to believe, you may run into design or detail errors within your retaining wall. This commonly happens when a designer doesn’t have enough information or has been given misleading or incorrect information. 

It’s important for designers to be communicative when building a retaining wall and for all information to be as accurate as possible from the beginning to avoid any preventable issues. 
 
Not only that, designers should check and re-check their drawings and the data for the construction to make sure that nothing goes awry. 
 
When you have design or detail failures, you’ll have to take a look at the root of the problem and consider an after-the-fact fix if the wall is still in a salvageable state. If you feel that you weren’t able to achieve this with your initial designer, contact Kelowna Retaining Walls today for help. 

Total Collapse of Retaining Wall 

While it’s not the most common type of retaining wall failure, sometimes a total collapse can happen. This means that some or all of the wall has given way, causing the soil that was being held back and causing damage to different areas of the wall and land around it. 
 
These walls are unable to be salvaged and need to be rebuilt. The good news is that these total collapses are a relatively rare phenomenon, and if you know what to look for, retaining walls will always show some preemptive signs of failure before totally collapsing. 
 
Make sure you always keep your eye on the grade of your wall, which can indicate a lack of reinforcement, too much stress and pressure, as well as structural issues. Also look out for cracking and any signs of drainage issue or failure. 

Local Retaining Wall Builders Kelowna

Looking to have your retaining wall inspected for failure detection? Are you building a new retaining wall in the Kelowna area? Do you need to have your retaining wall repaired? 
 
Kelowna Retaining Walls can help you address any of these issues and moreContact us today and we can set up a consultation to help with all of your retaining wall needs.

Kelowna Retaining Walls
Visit Website: www.kelownaretainingwalls.ca/