How to Choose the Right Armour Stone for a Retaining Wall
Written By:
Danosh Construction Inc.
19386 McCowan Rd, Mount Albert Ontario L0G 1M0
905-473-6883
When building an armour stone retaining wall, there are many items you may want to take into consideration. A retaining wall isn't just any wall; it will need to be sturdy, strong, and support its own weight, including the weight of the material it is holding back. Stone retaining walls serve a dual function of retaining soil and acting as an attention getter while adding elegance to your property.
1. Plan where the wall will go.
Before placing an order for stone or beginning construction, you need to plan out the wall you want to build. Questions that you will need to answer for yourself are:
- Where is the wall going?
- How tall does it need to be?
- How long does it need to be?
- What type of material is it holding back, and how much?
Look at your property and identify the area the wall is required to go. Measure the length, width and height it will need to be. Depending on its location, you may need to taper the wall if it is heading down a hill. These measurements are very important because they will determine how many tonnes of armour stone you will need to build your retaining wall.
2. Pick out the stone you want.
It is not well known that armour stone comes in a variety of shapes, sizes, and colours. Most people skip this step and don’t really know what kind of stone they are looking for. There are two different types of armour stone that can be used to build a retaining wall: Guillotined armour stone, and Natural armour stone.
Guillotined armour stone is custom cut with a large saw. They have clean lines and fit nicely together. Often these stones will be used if you are building a retaining wall in a small space or confined location. For example, if you are putting a small wall beside your house, but only have a few feet between you and your neighbours home, you may want to have smaller cut stone in order to fit the wall into the space. Custom cut stones are easier to place, as these stones can be cut perfectly down the side, allowing them to fit snug together, to achieve a nice, clean look. This will eliminate gaps in the wall and could be safer in public places. Notice how smoothly the stones transition into each other in the photo below. It looks like one big rock!
Natural armour stone is stone that comes right out of the ground. “Regular sized” armour stone is usually between 2’-3’ wide and between 3’-5’ long, but there are many different sizes you can get. The variability with these stones is in the height of each one. Remember, each stone is a little different, so when placing them you need to find the right ones to fit in the right places. There may be gaps, but that is part of the look of a natural armour stone retaining wall.
You will need to order the proper height of the armour stone.You can get armour stone in heights ranging from 10” all the way up to 24”. This is usually done by taking the total height wall you would like to build, and dividing it by the number of rows you would like to work with.
For example:
An approximately 6ft high retaining wall could consist of 4 rows of 18” stone, 5 rows of 14” stone, or 3 rows of 24” stone.
The height that you choose to work with, will mostly depend on the size of machine you (or your contractor) have available to maneuver the stone, as machines are limited by the weight of each piece. Larger stones may look nicer and take less time to place, however they are much heavier and require larger and more expensive equipment on site.
Finally, you will need to decide on a colour of stone that you wish to use. This step is not very hard, but it could impact the overall look and feel of the wall or property. Standard armour stone colours are light grey, dark grey, chocolate brown, and beige. However, there are many more, so be sure to do some research into what colour you like best. Remember to match it to the rest of the landscaping around your property!
3. Order the armour stone and have it delivered.
Once you have determined the dimensions of the retaining wall you want to build, and have determined the colour and size of stone you need, it's time to order and have it delivered. You will need to provide the company you’re purchasing the stone from with the dimensions of the retaining wall, so that they can give you a quote on how many tonnes may be required. Make sure that when placing an order, you are getting the exact stone you want, in the right size and colour, and verify it with them! Then place the order.
Our trucks will pick-up the stone from the proper location (depending on the size and colour ordered), and deliver it to site. There are two ways armour stone can be delivered: a flatbed trailer, or rolloff bins.
A flatbed is the most common way that regular sized armour stone is shipped and will require a forklift on site to offload it (usually the landscaper you hired will help you with this). If you do not have a way to offload the stone yourself, ask for a Moffett forklift. This is a small forklift that attaches to the rear of the flatbed trailer. It can be used by the driver to offload stone, but will cost extra.
Flatbed trucks can not load and deliver armour stone that is too small to be safely secured onto the trailer, these smaller sizes of stone are shipped in a rolloff truck and trailer. These loads are carefully dumped onsite to allow the stone to roll out of them, meaning you will not have to have someone offload the stone. Don't worry, it usually won't hurt the stone!
Please keep in mind that delivery drivers just unload it onto a designated area. Your landscaper will place the stone for you.
ATTENTION! Armour stone is NOT sold by the size of the stone! This is because each stone is a little bit different. It is sold by the total weight (usually tonnes). This is why the measurements you took earlier are so important because they will determine the tonnage that you need.
4. You are ready to have the retaining wall built.
Work with your landscaper to build the retaining wall exactly how you envisioned it!
Helpful Tips
Beyond building the wall, there are some things that you should focus on:
Make sure you use good quality stones. They will need to not only hold their own weight, but also the weight of the material behind them! Try to minimize the amount of gaps in the wall. This will ensure a clean look, and will be safer from things getting caught in them (like little fingers and such). Make sure there is lots of drainage behind the wall. Water collecting behind the wall could cause it to collapse. Match the wall to the rest of your landscaping. You don't want it sticking out like a sore thumb. Make sure the theme of your house, and your personal taste bode well with it!