Retaining walls can be made from wood, bricks, natural stones or concrete blocks. For DIYers, it's easiest to use concrete retaining wall blocks that interlock.
Gravity retaining walls
They are the simplest and earliest recorded type of retaining wall. Built of concrete, masonry, brick, blocks or mass cast-in-situ concrete, these hard-wearing structures rely on their large weight to resist toppling and sliding caused by the lateral earth pressure from the soil behind them.
Timber and interlocking concrete-block walls are the most accessible options for DIYers. These materials are relatively easy to work with and don't require specialized skills or equipment.
In summary, retaining walls do need a footing to ensure they are structurally sound and have proper drainage to prevent cracking or collapse. Without a footing, the ground beneath the retaining wall can shift, which can cause the wall to shift as well, leading to cracking or collapse.
Rules of thumb commonly used by designers to establish the geometry of the wall include (refer to diagram): Base width = 1/2 to 1/3 of the height of the wall. Base thickness = 1/8 of the height of the wall but not less than 12 inches. Stem thickness = 6 inches + ¼ inch for each foot of wall height.
Absolutely! Even a 2-foot retaining wall needs an effective drainage system. Without it, water can build up behind the wall, leading to pressure that might cause the wall to lean or even collapse. All walls need systems to manage water effectively, preventing damage over time.
Plan to backfill the wall with well-draining gravel or sand. Higher walls or areas with soil that stays wet may need a drainage pipe. Keep in mind that clay soil retains water and sandy soil drains too easily. You'll need a well-draining soil mix behind your landscape retaining walls.
Options like concrete blocks, timber, stone, or brick vary in price, with concrete blocks often being the most cost-effective. The quality and source of these materials also influence the price.
In this case, you would need to excavate a base that is at least 2.5 feet deep to provide adequate stability for the wall. Understanding the importance of depth calculation is crucial when constructing a block retaining wall.
What Is the Cheapest Material to Build a Wall With? While prices of materials will vary depending on where you're building, the least expensive types of siding for exterior walls tend to be vinyl and composite. Vinyl is synthetic, low-maintenance, and comes in all different types to match aesthetic desires.
Walls made of concrete retaining wall blocks less than 3 feet tall can be built by do-it-yourselfers, but anything taller requires a professional. Considerable knowledge and experience are needed before undertaking such a project. Research local building codes, especially if erosion and runoff are concerns.
Controlling the Height of the Wall
Adjusting the height of the retaining wall can lead to significant cost savings. In scenarios where it's feasible, reducing the height of the wall while allowing for a gentle slope can decrease the amount of materials needed and thus the overall expenses.
Hydrostatic Pressure and Wall Failure
When water isn't properly drained, it can accumulate behind the wall, exerting pressure on the structure. This pressure can prompt the wall to shift, crack, or even collapse. To avert such failures, it's crucial to have adequate drainage behind the retaining wall.
Excavation
Dig a trench for the bottom row of blocks. They should be buried about 1 inch deep for every 8 inches of wall height. This provides strength and stability to your retaining wall. Make sure that your trench is level and compacted.
You may be wondering what the situation is when a retaining wall might be necessary – let's take a look! In most cases, a retaining wall is needed when the slope of the land exceeds a certain angle, usually around 4:1.
Do you need drainage behind a retaining wall? Yes, which means you need backfill too. This backfill is the soil that's located in the first 12 inches of space right behind the retaining wall in order to have proper drainage, and it can be either gravel or crushed stone.
Medium Walls (4 to 10 feet):
The thickness can vary between 12 and 18 inches, contingent upon slope and soil characteristics.
Gravity retaining walls
Built of concrete, masonry, brick, blocks or mass cast-in-situ concrete, these hard-wearing structures rely on their large weight to resist toppling and sliding caused by the lateral earth pressure from the soil behind them.
Retaining walls are functional features that keep soil in place and turn sloped land into flat, usable space. Typically, your retaining wall should be between 3 to 4 feet tall to serve its purpose without requiring structural support and intricate engineering.