For walls built from concrete, cement, brick, or cinder blocks, you'll want durable, concrete footing.
You can build a block wall internally in a building on the slab, if it's a free standing ,it most certainly will need a footing and the foundation will depend on the ground bearing pressure of the soil, clay, they can have deep or shallow foundations.
A durable retaining wall can be built without using concrete by using carefully fitted boulders or cut and dressed stone pieces. These are usually quite massive, as their stacked weight alone is what counteracts the forces of gravity of the earth behind it which want to push it over.
The best base material is called HPB, high performance base. Alternatively 3/4 inch quarried gravel without any fines will also work as a base.
For larger retaining walls, a buried structural footing is typically needed. A landscaper pours concrete below the frost line to achieve this (the depth to which the ground will freeze during the winter). If moisture in the soil freezes and heaves, footings poured too shallowly are vulnerable to shifting and moving.
Backfill behind the courses of blocks to a width of 200-300mm using 10-20mm clean aggregate. Ensure each block is filled with clean aggregate.
These can include additional pressure, and soil saturation and freezing and expansion of the water. Water collecting at the bottom of a retaining wall is the leading cause of retaining wall failure.
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.
A drainage pipe might be needed if: The retaining wall is at least four feet high or taller. Clay or other poor draining soils are behind the wall.
In conclusion, while not all retaining walls require foundations, many do, particularly those that are taller, support heavier loads, or are built on unstable soil. The correct foundation ensures the longevity and safety of the retaining wall, making it an essential aspect of the construction process.
Building a basic retaining wall
The first factor before building an interlocking retaining wall is determining the depth of the foundations otherwise known as the footings. If the soil is firm and well-drained, 300mm should be enough. Alternatively, if the soil is not as firm and unstable, 450mm would be suitable.
The footing is a critical component of reinforcement and serves to keep your homes foundation wall standing and stable over time. Brick and stone structures are immensely heavy and without the right grade of footing, even the strongest foundation walls won't be able to provide necessary structural support.
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. The blocks should sit about halfway into the soil.
Cost and Availability: Cinder blocks can be more cost effective for simple, lightweight builds, while concrete blocks and cement blocks might be pricier but provide greater strength and durability. Environmental Factors: Think about fire safety, thermal insulation, and soundproofing.
In general, shorter walls with stable soil conditions may not require a footing.
Moreover, size and depth of foundation should be enough to resist overturning and sliding of wall. As a thumb rule, depth of footing of a free standing wall is usually 1/3 of its height to ensure stability. So for a wall of height 8 ft, its footing should be 2.7 ft deep.
RCNY §103-09 and Local Law 37/08, effective January 1, 2014, requires owners of properties with a retaining wall or part of a retaining wall which is at least ten feet high and faces a public right of way such as a sidewalk or entrance must have a condition assessment of this wall conducted every five years and the ...
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.
Longevity and Durability
One of the most appealing features of diamond block retaining walls is their impressive life expectancy. Thanks to their concrete composition and interlocking design, these walls can last 50 years or more with minimal maintenance.
Waterproofing will help to preserve the structural integrity of the retaining wall. Without waterproofing or adequate drainage, the retaining wall will suffer, this can come in the form of leaks, bulges, the wall bending, leaks in non-drain areas, and more.
Soil saturation is the most common external factor that causes retaining wall failure, but there are many ways to prevent it.
If you don't install adequate footing, your retaining wall will likely tip forward or bulge out over time. If you plan to use more flexible materials such as stone, wood, or bricks without any mortar, you can use a compacted stone footing.
Weep holes are a crucial component in the design and construction of retaining walls, serving several vital functions that contribute to the overall stability and longevity of the structure.
After each row is completed, you should use backfill to reinforce the retaining wall. Use crushed gravel to fill in the back and sides of your blocks. Backfill helps with water drainage.