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.
Yes, the retaining wall needs drainage stone to act as a filter. If you have a very short wall (less than 1' or so), you can probably do without, but everything else should have drainage stone. Walls greater than 4-ft or walls that support a slope or clay also need a perforated drain pipe that outlets every 30-50 feet.
How Deep Should a Footing Be for a Retaining Wall? The footing, or first row of your retaining wall, should be about 4 to 6 inches deep and about 12 inches wide, or twice the width of the block you are using.
Don't Forget To Backfill Behind Your Retaining Wall
Neglecting to backfill properly can lead to reduced support, increased pressure on the wall, and the possible collapse of the wall.
For proper drainage you need at least 300 mm of gravel or similar material directly behind the wall. If you're planning on landscaping behind the wall, allow for at least 150 mm of topsoil above the gravel.
The base of a retaining wall should be set below ground level. The taller a wall is, the further below ground level it should be set. Crucial for supporting the rest of the wall, a good base is made of compacted soil and at least a six inch layer of compacted sand and gravel.
Soil saturation is the most common external factor that causes retaining wall failure, but there are many ways to prevent it.
Even for a 2-foot retaining wall, there are benefits to adding a footing: Enhanced Stability: A footing provides additional stability, reducing the risk of settling or tilting over time. Improved Drainage: Footings can include drainage features, preventing water buildup behind the wall that could weaken it.
Filled Wall Blocks Promote More Efficient Drainage
Rainwater, snow, and ice can all accumulate inside precast retaining walls composed of hollow blocks.
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.
In conclusion, deciding between a cinder block retaining wall and a concrete one is a matter of preference. Both materials have unique benefits and drawbacks that must be evaluated before making a decision. Cinder blocks are often more affordable, but not as long-lasting as concrete.
Concrete block retaining walls must be stronger than freestanding walls. Insert rebar in the footing when you pour it; this should be done every three blocks or at intervals specified by your local codes.
Add an angular aggregate — clean, crushed stone or gravel between 1/2- and 3/4-in. — as a base under the retaining wall and as back fill behind it.
In most dry stone walls, water flows freely through them, so a drain pipe part way up the back is utterly useless. The cut stones in this wall fit tightly enough that water penetration will be slow, making it more imperative that there is good drainage.
Landscape Retaining Walls are a category of wall block that are most often used in residential yard and garden applications. Landscape retaining wall blocks are designed for small to medium sized walls, usually up to 3 feet (some up to 6 feet with engineering).
Does a 2 Foot Retaining Wall Need a Drainage Pipe? Absolutely! Even a 2-foot retaining wall needs an effective drainage system.
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.
Discover how the right retaining wall can reduce soil erosion, improve water drainage, and transform your property. Depending on the material, soil, and groundwater, a permanent retaining wall can last anywhere from 25 to 100 years.
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.
Disadvantages of Retaining Walls
One significant disadvantage is that they can be expensive to build. Retaining walls require careful planning and engineering to ensure they are strong enough to hold back the soil. Another disadvantage of retaining walls is that they can be difficult to maintain.
Any reinforced wall or walls over 4 ft. (1.2 m) in height or with slopes or other surcharges above the wall will need a toe drain.
One major thing to avoid when building your retaining wall is lining the back of your wall with plastic sheeting as this will surely result in the pooling of water behind the wall.
Dig A Trench To Outline The Space
Ensure the trench is wide enough to support both the retaining walls as well as any plants or flowers that will be added. Keep in mind that the fill dirt will act as a base for the entire feature, meaning any wall layers and plants should have a layer of fill dirt underneath it.