You may think that all retaining walls are pretty much built the same, and will last around the same amount of time, if the materials used to build the wall are similar. If you look around any neighbourhood, you will find some walls that are standing and look amazing, while some are failing and look less than desirable. Retaining walls can be made with the exact same material at the same time, and still not be built the same way. It is imperative to the longevity of your project to hire a contractor that knows the best practices for building a retaining wall, and will not cut corners on your project.
What to look for to get a lasting retaining wall
A contractor with training
You wouldn’t go to a DR. that wasn’t qualified, so why hire a contractor that isn’t? You may say to yourself that having a wall built is less important than your health and well-being and rightfully so. However, when having a retaining wall built, there are many things that can go wrong. If your contractor does not know how to build a retaining wall properly, your wall could fail, causing damage to not only the wall itself but your property, and home. What is even worse, if anyone is near the wall when it fails, they could get seriously injured. Walls that are built incorrectly will have gaps and holes in them, or look unsightly due to waves in the wall taking away from the aesthetics of your yard. Whether your wall is failing or looks bad, you will need to get it redone, adding more stress, time and money that could have been avoided by hiring a professional to build your wall.
Type of material used
Unless you love the look of wood, there is really no reason why your contractor should be recommending that your wall be built with it. Allan Block concrete is a material that lasts a lifetime, whereas retaining walls built out of wood last 10+ years. Because Allan Block is made specifically for retaining walls, the wall will never rot or decompose. Another plus for using Allan Block is that it is safe for the environment.
Proper soil excavation
One of the biggest parts of a retaining wall project is excavating the soil. Excavating the soil takes skill and time, and if you want it done right, proper machines. If your contractor does not have machines that can excavate and move soil from the back of your yard to the front to be hauled away, it can be time consuming and messy. The amount of soil that comes out of the ground grows by 1.3 times its size once excavated, and will need to be hauled off site with a dump truck or trailer. If these are not available to your contractor, you could be left with unwanted piles of dirt in your yard.
The reason you want to excavate a lot of soil is that you want to be able to replace that soil with gravel. If only a little bit of dirt gets excavated for your wall, the amount of gravel that gets put in its place is not going to cut it, and your wall will fail from lack of gravel being put in.
Having enough gravel for your wall is imperative because gravel is essential to the base of the retaining wall. It provides a solid level of foundation to build on, as well as allows any water to drain through the gravel. Again, if your contractor does not have the right equipment, it will be difficult for them to bring in the proper amount of gravel for your wall, as it will need to be brought in by wheelbarrows.
The wall below is failing because there is no gravel behind the wall.
Burying the first row of bricks
Burying the first row of bricks aids to the strength of the retaining wall, and makes sure that the wall does not slip out. This takes extra work, and can get skipped because the contractor does not have time to do this step. If this step is skipped, your wall could slip out, causing major damage to the wall and surrounding areas.
Core filling the back of the wall
When filling the bricks with gravel, it is not uncommon to see contractors core filling just the middle of the wall. The back of the wall needs to have gravel. Allan Block requires a minimum of 16” of clear draining rock or 12” of no fines concrete directly behind the wall, and prefers the infill soil area to be a compact-able material such as ¾” minus or road-base. Most contractors do not abide by this, and if your wall is not built using proper backfill material, you will have a problem with your wall.
String lining the bricks and caps
You want your retaining wall to not only last but look great, as it is surely a focal point to any backyard space. It is not easy to get a wall to look completely straight, and takes time and skill to lay the bricks properly. If the bricks are placed quickly, this can cause your wall to look uneven and wavy. If even one single brick is out of alignment, the entire wall will be.
This can be avoided by string lining both the bricks and the caps, and being meticulous in laying them. By laying each brick one at a time, and making sure that the brick is level from side to side and front to back, your wall will be straight, and wave free.
When hiring a contractor to build your retaining wall, be sure to ask them the following:
- What courses have you taken related to retaining wall builds?
- What material do you plan on building with?
- How much soil are you going to be hauling out of my yard?
- How much gravel are you using, and will you be filling the back of the wall?
- Will you be burying the first row of bricks?
- How do you ensure that my wall and caps are straight?
- What machines do you use?
- What is the timeline for this type of project? (You do not want a contractor who thinks that they can complete a wall in a day or two. This is a red flag that they are wanting to be in and out as quickly as possible, and will cut corners to do so.)
When having any project done at your place, be sure to do your research, and learn best practices ( read best practices for retaining walls) for the job you are wanting to have completed. By being educated, you can find a contractor that is a great fit for you and your family, and enjoy the beauty of your yard for years to come.