What kind of gravel do you use to backfill a retaining wall?

The base material, wall rock, and drainage stone all require a quarried backfill. Although you could use different materials for each, I recommend sticking with just one material for all three zones. This should be a clean crushed rock, like a #57 or #78 stone, 3/4″ crushed rock, or clean crushed limestone.

Can you backfill a retaining wall with gravel?

Second, a retaining wall must have properly compacted backfill. Backfill refers to the dirt behind the wall. In order to provide proper drainage, at least 12 inches of granular backfill (gravel or a similar aggregate) should be installed directly behind the wall.

Should retaining wall blocks be filled with gravel?

Stacking retaining wall blocks is easy. However, keeping them stacked for years is difficult. That’s why your DIY retaining wall must have a solid gravel base and firm backfill to ensure it’s stability.

How much drainage gravel do I need for retaining wall?

300 mm

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.

Which gravel is best for drainage?

Crushed gravel is one of the best choices for drainage. Use #3 or #57 crushed stone for your drainage needs. Select an angular crushed gravel—smooth stones drain poorly. Gravel between 0.5 and 1.5 inches is the best choice for drainage.

What is the best material to backfill a retaining wall?

The best material for the backfilling of a retaining wall is gravel, and it should be well graded. The main reason for using gravel is because it does not retain water (small void ratio); hence lateral loads experienced will be minimal. You should also have weep holes for draining excess water that may be retained.

Does a 3 foot retaining wall need drainage?

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. There are buried water sources within 50 feet of the retaining wall location.

Does a 4 foot retaining wall need drainage?

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. In all cases wall rock is located within the cores of the block and a minimum of 12 in.

What do I put behind a retaining wall for drainage?

For proper drainage, the first 12 inches of space behind a retaining wall should be filled with crushed stone or gravel. This is so that when water gets into the space, it does not become bogged down in soil but instead can flow down the wall to the drains or weep holes.

Is sand or pea gravel better for drainage?

Avoid using round gravel, such as pea gravel, since it will compact and prevent drainage. Similarly, sand does not make a good drainage bed. Gravel is the best choice for drainage ditches, paths, and driveways.

Is pea gravel good for backfill?

Provided these conditions are met, pea gravel fill is a viable option for use as select backfill for flexible pipes.

Does a 2ft retaining wall need drainage?

Every retaining wall should include drainage stone behind the wall. Though it is a good idea to install a drainage pipe on all walls, there are certain situations where a perforated drain pipe is absolutely necessary.

What kind of gravel should I use for drainage?

Crushed gravel, sometimes referred to as crushed stone, is excellent for providing drainage. The best type of gravel to use is one that is made up of angular stones. Smooth stones will interlock tightly and drain poorly. #3 and #57 crushed gravel are both excellent choices for most drainage needs.

Do I need drainage for a 1 foot retaining wall?

If your retaining wall needs a drainage pipe, make sure the pipe has slots on all sides, not just one. 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.

Is bigger or smaller gravel better for drainage?

Size Matters
Larger-sized gravel will be more ideal for drainage. Stones with a size of half an inch to one inch across are the right size for blocking debris, yet allow for water flow. Larger rocks won’t accidentally become compacted during heavy flows.

What kind of gravel is best for drainage?