Repairing a Leaning Retaining Wall

Lead Image
  • 4-100 hours
  • Beginner
  • 200-25,000
What You'll Need
A Helper or Two
Sturdy work clothes, gloves, and boots,
Eye protection
Shovels
Wheelbarrow
Chisels
Hammer
Mallet
Hose
A Civil Engineer
Cement Mixer
Excavator
Mortar
Trowels
Replacement Blocks, Stones, or Concrete and rebar as needed
Water

Repairing a leaning retaining wall can indicate a major underlying issue, so it's better to address it immediately before it comes crashing down altogether. A retaining wall is not only aesthetically pleasing, but it also serves to hold back the land from encroaching upon your living spaces. If your retaining wall is broken up, cracked, crumbling, leaning outward, and or, falling down, then it's not doing its job and requires immediate repair.

Retaining walls stop topsoil erosion and flooding by diverting water flow away from the affected area and enhance your landscaping while keeping the landscape from coming into your house and tracking mud all over the carpet. Due to the nature of the forces in play behind it, a retaining wall has a lot to stand up to. They are very durable and will last a long time, but time takes its toll on everything and after 50 years of withstanding such extreme forces the structure is bound to become weakened and damaged.

Clearly, that is something that you cannot allow to leave unattended for long because as hard as it is to hold the land back it's much harder still to move it back again, and again. This article will show you how to do it yourself like the pros.

wood retaining wall containing dirt

Advisory

You are strongly advised, as always, to consult with your local Building Inspector's office to make sure that you will not run afoul of any city, county, state, and or federal building code compliance issues that could prove costly in the long run. Doing unpermitted home improvement, or construction projects might be convenient and save you money today, but if you try to sell the property tomorrow and have to tear that project back out again it's probably going to cost you a whole lot more than doing it right the first time. Possibly even the property itself.

It can never be overstated that you have a responsibility to yourself, your family, and your employer, or employees to follow all rules of safety involved in this and every do-it-yourself project. Complacency and lack of knowledge can be deadly by themselves but combined they're a recipe for disaster, one that can have far-reaching consequences. Consult with local home improvement experts prior to initiating your project, and always do your homework with regards to instruction on techniques, and safety. The more you know in the beginning, the better your end results will be.

Common Causes of Retaining Wall Damage

Any retaining wall taller than one foot should utilize the following features in order to be at its very best in the future. It must be battered backward against the land it's meant to retain and it should be anchored securely into that land by tie backs. The retaining wall should be built upon a bed of gravel that will allow the wall to shift and move as the ground does so it is less likely to become unstable. It should have a firm footing in the ground beneath it and good drainage to keep the soil behind it from becoming too saturated and less stable.

Where any one or more of these elements are not in play the life of your retaining wall will be decreased significantly and it will weaken more quickly. Repairs will not last and will likely become necessary again before long. Even if they are used, drains can become clogged by roots invading them or from debris passing through them. If the foundation is unstable or the retaining wall becomes undermined by tree roots, or if the ground should shift suddenly during an earthquake or landslide it will also shorten the life expectancy of the wall.

By taking all of these factors into consideration before building your retaining wall or when examining an older existing one you will be able to build it to last or repair it so that it will last even longer.

Prevention

An ounce of prevention is always worth a pound of cure and it's just as true for dealing with a retaining wall regardless of whether it's old or new. Making sure the job is done correctly will always be the do-it-yourselfer's first best line of defense.

No chain is stronger than its weakest link and in the instance, it's the mortar that makes up the weakest link in the retaining wall system. Considering that it's being assaulted from both sides by different forces of nature, Sun, rain, wind, snow, on the front side, groundswell, earth movement which does happen a lot more than you might think as the tectonic plates move around in their Earth mantle beds. Add to that list, flooding, tree roots, frost heave, and would you believe it? Even the nearby flow of heavy traffic on the streets plays a small yet significant part in the ultimate demise of your retaining wall and mortar takes the brunt of it due to its own nature.

If it is showing signs of severe damage and age it must be repaired. To do so simply chisel out the old mortar down to about halfway beneath the brick and put fresh mortar in its place and do the same thing anywhere else you find damage as you find it.

Cracked or Broken Bricks

crumbling retaining wall of large concrete blocks

It's not only unsightly but weakens the structural integrity of the wall to keep a broken or cracked brick within the wall as it tends to travel to other bricks. That is the nature of the force playing upon that point in your wall and like the Karate Master's hand that force will slowly continue to transmit that crack through any adjoining bricks if left to do so. Repairing the broken bricks with this in mind will allow you to better see how to alleviate that force and repair the broken materials as well.

Each situation will differ and there are numerous resources available to read up on and professional resources that can diagnose the problem if you are unable to. There's no shame in asking for help when in fact it is almost mandated. To repair the brick simply chisel out the old mortar from around the brick and remove it. Mix and reapply a thick layer of fresh mortar to the base where the new brick will sit. Place the new brick on the mortar and seat it gently with a mallet, then apply mortar around the top, and sides filling in all the space around it. Use a trowel to smooth he surface out and allow it to cure. Repeat as needed.

Evaluating a Leaning Retaining Wall

If your retaining wall is severely damaged and you should consider taking the wall down and rebuilding it after addressing the underlying issues that brought it to that point. In all cases, it should first be inspected by an engineer who will evaluate the problem more comprehensively than you probably can and give you a clearer picture of the interplay of the forces acting on the wall and causing the damage.

cracked concrete retaining wall

The drainage system should be evaluated and tested and a hose will facilitate that test. Restore or replace any and all defective drains and consider ways of diverting water flow away from the wall if possible.

Consider the effect of any loads on the surface such as a newly built recreation room or patio that were not there when the wall was erected. Your wall will need to be gusseted to account for that weight. If you are going to add weight or more weight behind the wall consider constructing it on piers, or taking other steps to alleviate that load, even increasing the footing and reinforcing it, because that weight has to go somewhere.

If the roots of a tree have undermined the wall then it may have to be removed and replanted if possible. Planting trees around a retaining wall is never a good idea and should be kept in mind.

If the wall needs to be re-anchored you will have to excavate the soil behind the wall and install a new anchoring system. Consult with an engineer prior to undertaking this step as it will save you a lot of time, and money. Nothing worth doing should be done wrong when the same effort would make it right, otherwise, twice the effort might repair it. If you're lucky that is. Consult with professionals on what anchors will work best and make sure they are feasible for you to install before you attempt to do so.

In most cases, a leaning retaining wall is probably going to have to be taken down and rebuilt after these, and other issues that might be unique to your homesite are addressed. Using the old bricks will save a lot of money and you still have the same aged retaining wall to accentuate the beauty of your landscaping. This is also a great project for the beginner or the professional do-it-yourselfer to tackle.

I helped my father build a retaining wall made of concrete to hold back a mountain in Ventura, California in 1969 when I was 6 years old and it worked until it was removed later by a new owner who probably now has no back yard like the neighbors did. The wall was 6 feet deep at the base of the footer and 2 feet thick, and 6 feet above ground level and had enough extra rebar in it to sink a battleship. But he and I built it ourselves with shovels, hand tools, a cement mixer, and a wheelbarrow, and so can you.