What to consider before building a retaining wall?

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Natasha Maerz

Owner/Office Manager

Retaining walls can bring a ton of curb appeal to any space, and they do the important job of holding back soil, or giving homeowners more coveted yard space. 

Retaining walls looks pretty straight forward, but what should you know before having a retaining wall built?

At Back 40 Landscaping our expertise is in building Allan Block retaining walls. We are trained and Certified in building Allan Block retaining walls, and have a passion for building retaining walls that actually last. 


What material your wall should be made out of

When thinking about what material your retaining wall should be made out of there are many things to consider.

  • Longevity
  • Style
  • Material
  • Access to the space
  • Impact on the environment


The two most popular material options for a retaining wall are wood and concrete.

Concrete Retaining walls 

Concrete retaining walls come in tons of different colors, and styles, and while all of them typically have the highest cost,  they will last almost indefinitely.

The most recognized name in concrete retaining walls is Allan Block, but there are other brands such as Valley Stone, offering this relatively lightweight, long lasting retaining wall option.

The Lifespan of the retaining wall material should be top priority when choosing what type of retaining wall material you are going to have installed.

Most contractors prefer Allan Block because of their colors and design, and the fact that they will last a lifetime.

The Allan Block company has an extensive contractor training program to ensure if you want to build them correctly you can, and they are always available for consultation and help if needed.

Allan blocks are easily curved, and cut to make almost any size or retaining wall design.



Wood retaining walls can be a lower initial cost, and are more DIY friendly.

They will last several years if made out of regular lumber, and upwards of 10 years if built with pressure treated wood.

They can last even longer if made out of pressure treated wood  rated for ground contact.

While wood retaining walls  have a lower initial cost, they will have to be replaced at some point.

They have the shortest lifespan and lowest resale value and unfortunately have the fewest color and design options, as paint and stain do not adheres well, and curves are a lot more difficult to accomplish.

The Look You Are Going For

When thinking about your retaining wall design it is important to look at what your yard or space already looks like, and the “feel” that it gives off. 

If your home is modern, with lots of stone or paver work, you may want to go with a modern looking material.

If you are out in the country and there are lots of wood elements within your space, you could consider going with a Concrete block that looks like wood (Techo-bloc and Barkman have amazing options for these), or use real wood.

There are so many different styles, colors and options for retaining wall blocks that it can easily become overwhelming.

Luckily homeowners that are overwhelmed with what to choose, or those who just don’t have that “artistic eye” can easily hire a designer to help.

Will my wall need a permit and/or engineering?

This is a big concern for homeowners wanting to have a retaining wall built on their property, and rightfully so! You want to make sure that you are following your cities guidelines and doing things right.

Retaining walls that are less than 4’ can be built without a permit or engineering, and almost as high as needed with professional engineering and a city permit.

The 3 main factors are city building requirements, the type of soil on site, and the retaining wall block manufacture specifications.

Most cities in the Fraser Valley allow walls under 3.9’ to be built without a permit or engineering.

If the wall is over 3.9’  a building permit and engineering are required. Some cities also have a bylaw stating that you can’t build a large wall if it doesn’t fit with the neighbourhood.

The 2nd factor is the onsite soil type. Soils that are heavy clay retain water, and are very heavy.

This may mean that structural precautions and overbuilding may be a really good idea, even on a smaller wall under 4’ in height.

You may want to build a wall to an engineered standard even if it is not required.

The 3rd factor is closely related to the site soils. Manufactures like Allan block have a chart that says the wall height for common applications.

These wall heights can be as low as 13” tall when they start to require additional structural components.

To summarize, there are a lot of influences and factors that set the maximum wall height.

Some retaining walls can be simple and built to a height of 4’, while others will need some structural support for walls that are only 13” tall.

For every retaining wall you should at least consider what forces will be applied to this wall, as it will need to stand up to them for a lifetime.


Should I build my retaining wall myself, or get a contractor to do it?

Building a retaining wall may seem pretty easy, however, there are a lot of factors that go together to build a truly sound wall that not only looks great but functions as it should.

We take pride in our yard’s appearance, and spend countless hours mowing our lawn, trimming our hedges, and pulling weeds in our garden.

It is important to us that we take care of our home, and we get a certain satisfaction from being able to tell our friends that we did the work all by ourselves.

We understand having pride in our work, but there are some things that really should be left to experts.

While there is a lot of information on the internet and in books on how to build a retaining wall, a lot of skill and knowledge is required to install a wall that is going to not only do its job, but last more than a couple of years.

Most walls are not built correctly whether from contractors and/or homeowners cutting corners by not using enough material (gravel) or not following proper specifications ( digging the trench deep enough).

If you drive around any neighbourhood you will easily be able to find dozens of retaining walls that have failed, or are in the process of failing. This is even true for walls that are not that old, or walls that are built out of concrete that were installed incorrectly. 

To build a structural retaining wall takes considerable effort, and skill.

To build a reinforced retaining wall that will last, it takes the proper hand tools, gas powered concrete saw, laser level for perfect accuracy, string lines for straight and true walls, and the combined construction experience to put all this together, and to address potential issues before they become a problem.

There is also a fitness requirement, ability to handle stress, and working in the elements. As well as a skill to run heavy equipment: Excavators, skid steers, dump trucks etc.

From our experience, unless you are homeowner that has had professional training on how to build a retaining wall it is best to hire a contractor rather than DIY a retaining wall.

What “add ons” you would like for your retaining wall

Retaining walls that are built properly can be a focal point in their own right, but there are some extras that homeowners can add on to their wall that can really enhance the beauty of both the retaining wall and the landscape around it.

Curves Or Tiers

If you want to take your focal point to the next level consider adding curves to your wall, or having a tier in your wall.

Avoiding a typical straight wall will give your retaining wall a unique look.

Flower Beds

Consider what type of plants and flowers are going to be in front of, on top of, and around your wall, and adding colourful  flowers can enhance your walls look, and keep it looking nice and fresh.


Nothing makes a retaining wall look better than adding some sort of light. In the summertime the lights will add ambiance as you bbq and hang out around a fire, and in the winter will give a cozy feel to your outdoor space.


Incorporating stairs into your retaining wall not only allows you to reach what is above your wall, but add a look of luxury.


Before having a retaining wall installed take the time to ensure that you have a plan, a capable contractor to do the job, and know the style and look you want for your wall.

This will prevent you from regretting getting your wall done, and allow you to enjoy this investment.