For split-faced retaining wall blocks when it comes to corners, an installer has to expose the split-face on the side of the block which is usually a smooth surface. To this day most manufacturers leave this to the installer and do not produce split-face corner units for retaining walls.
They are made using a dry-cast concrete that is placed into a mold. This concrete is vibrated and compacted into the mold. When the product comes out of the mold it has groves in it that are then split along those grooves after the product is kiln dried. These split grooves are what reveal the face of the wall units providing a rough wall face with the concrete aggregates showing through along with the color blend of the wall itself.
Rock Face Retaining Wall Blocks
Split-face or rock face retaining wall blocks have been produced for decades in the hardscape industry. They have been relied on for small and large format retaining wall blocks. The traditional appeal to the blocks have helped them remain in style for the right application.
Despite their initial popularity and sustained use in the industry, most manufacturers never created corner units for these walls. Corner units would require an additional step in the manufacturing process for a product that would not sell anywhere near to the same volume as the main wall block. However, corner units are made for larger format split face block and other styles of wall block that are not split face because it would not be possible to achieve the same look on the side of the block if not for that step in the manufacturing process. And so, split face wall block has almost always been left to the installer to create the split face.
Split face wall block also has the benefit of being shaped to any angle that the wall may turn at. For example, if you do not have a 90 degree corner but a corner of greater or less than that then a split face wall block may be your best choice for a wall block product. This is because they can be shaped at any angle to reveal that split face. Whereas another wall block cannot be shaped whether cut or chiseled to keep the same appearance that is on the face of that wall block.
It is important to note that when you split a wall block that is not a solid block, anything you split will show. For example, some wall blocks have hollow groves on their surface or underneath for a locking mechanism. Others have groves that protrude out for them to lock to one another. If you split that block, those groves will show. Most split face wall blocks will be sold in a layer with a variety of shapes and sizes, but will have a specific corner unit that is solid on one end of the block without any grooves. It is this block that you will want to choose to split it so there are no grooves showing. Some products you will just have to settle with what is available.
Splitting wall block is not an overly difficult process with the right tools. There are two ways to do this, one requires more labor and skill than the other but is less expensive while the other is easier, requires less skill, but is much more expensive.
You always want to make sure when you are working with hand tools to use the proper personal protective equipment. For splitting wall block, this includes safety glasses, gloves, and hearing protection when necessary.
How to Chisel Retaining Wall Block
When it comes to chiseling a wall block to reveal a split-face, you will require a chisel with a 4 inch blade or longer preferably and at least a three pound hammer. It is a small investment, but will require more time to chisel each wall block and the skill to be able to do so efficiently and effectively. It will take some time to get into the rhythm of doing this and producing a quality product.
Start with a cut line for where you want your block to end for the split face. It is best to have it at least one inch from the edge of the block to ensure that the split comes off in one piece and you do not have to do any clean up. Put your wall block on a level surface. Place your chisel edge on the line and start creating a groove on the surface of the wall block hitting it a couple times along the line. Continue that line along the sides of the wall block with the chisel and then on the bottom of that wall block. Flip it back over and continue this same process increasing the intensity of the strikes with the hammer on the chisel while you go around the wall block. Usually this takes three rotations around the wall block to complete a perfect chisel of that block.
If only pieces come off rather than the entire side, continue your strikes if you still see your line. If you have a taller wall block, sometimes when the entire side does not come off it will hold onto a smooth surface in the center on the side of the block. You can use your hammer and chisel on this area to try and break it off, but sometimes a pointed chisel works better for this.
If you are very careful you can begin the groove with a saw and diamond blade along the cut line before continuing with your chisel. Doing so will reveal a smooth edge where that cut was before the rock face depending on the depth of your cut.
How to Guillotine Retaining Wall Block
The process of splitting a wall block with a block splitter or guillotine is a much easier process and provides a perfect split so long as the cut line is lined up with the blade and the wall block is level when placed on the cutting platform.
This is a much easier process that requires minimal skill, but does involve a much larger upfront investment. Purchasing a block splitter or guillotine is perfect for a hardscape business that installs a good amount of wall block in a season to make it easier on their employees, to provide a quality end product for their clients, and to make their job site safer in general.
To use a block splitter or guillotine, the blade needs to be raised or lowered to the correct height. This usually involves removing and inserting a pin or some sort of screwing mechanism to raise and lower it. Once there is enough clearance for the block, the user can place the block on the platform lining up the cut line on the block to the block splitter blade. The handle of the splitter can then be lowered to the cut line and pressure can then be applied downward to lower that blade further until the wall block splits off entirely. If more leverage is required, the user can add a bar to the handle to allow them to push down on it.
If you are not requiring to split wall block consistently as an owner of a hardscape business, you may opt to rent one of these block splitters or to purchase a chisel and hammer if you do not already have one. Just make sure whether you purchase a block splitter or rent that you want to purchase one that is capable of splitting the height of the wall block that you have. There are several block splitters that will do product that is less than 5.5 inches in height, but there are wall blocks that are popular that measure 6 inches.