what is the best base course for a retaining wall

Constructing a Retaining Wall

• Support. When building a retaining wall, landscapers often slope them slightly toward the earth they’re containing.
• Foundation. A trench filled with gravel provides a suitable foundation base for a short, step-back retaining wall with three-five courses (each layer of blocks is called a “course”).
• Backfill. ...
• Drainage Details. ...

Full Answer

What is the best foundation for a retaining wall?

Jan 14, 2021 · Moving forward, you should start from the lowest point to dig a base trench for the entire length of the wall. It should be 24 inches wide in most cases—this is the standard width of retaining walls. The depth of the trench should be six inches, plus an …

How far below the ground should a retaining wall be?

Make minor adjustments by tapping the retaining wall blocks with a dead blow hammer or by placing up to 0.5 in. (13 mm) of coarse sand under the blocks.; Irregularities in the base course become larger as the wall stacks up. Careful attention to a straight and level base course will ensure a quality finished wall.

How do you level a retaining wall with gravel?

The trench you are going to build your retaining wall in should be wide, deep, and level. Size the trench so there’s enough room for the block and at least 8 inches of space behind it. Excavate deep enough to completely bury at least one full course, including space for 6 …

What is the best type of retaining wall block to use?

To keep the blocks on your retaining wall level and structurally sound, you need a base layer of several inches of well compacted, sharp gravel. A handheld tamping tool can really help in getting the gravel level, but you’re right – one stray stone can throw off the entire operation!

How deep should a base be for a retaining wall?

The trench you are going to build your retaining wall in should be wide, deep, and level. Size the trench so there's enough room for the block and at least 8 inches of space behind it. Excavate deep enough to completely bury at least one full course, including space for 6 to 8 inches of base material.

How do you build a base for a retaining wall?

2:474:13Retaining Wall Base and Block Leveling Techniques Segment 1YouTubeStart of suggested clipEnd of suggested clipProcess must be compacted using a ramming compactor for tight corners or for very small jobs. YouMoreProcess must be compacted using a ramming compactor for tight corners or for very small jobs. You can use a hand tamper. Rule number five the site must drain away from the wall.

Do you put sand under retaining wall?

Compact the material making sure that it is compacted enough for you to walk over the area where there is no shift at all. When the base material is compacted it is also recommended to spread a 1� layer of coarse sand. This will help the wall settle evenly. So, make sure the sand is level also.

What type of gravel is best for retaining walls?

Replace native soil with 3/4-minus gravel (no stones under 3/4 inch in diameter) or "bank-run" gravel (washed stones 1/4 inch to 6 inches in diameter). Shovel at least a 4-inch layer of gravel onto the landscape fabric. Grade this layer so it slopes 1 inch for every 4 feet, allowing water to drain away.

How thick should a footer be for a retaining wall?

The footing dimensions will largely be determined by the size of the wall. A poured concrete footing for concrete, block or brick walls should be at least twice as wide as the planned wall. The footing should be at least as thick vertically as the wall's planned width.

What do you put under retaining wall?

0:254:19Retaining Wall Base and Block Leveling Techniques Segment 3YouTubeStart of suggested clipEnd of suggested clipNumber one directly on a gravel base. 2 on a mortar bed over a gravel base. 3 on precast levelingMoreNumber one directly on a gravel base. 2 on a mortar bed over a gravel base. 3 on precast leveling slabs and 4 on a poured concrete pad. All four methods work well but each has its own advantages. And

How much paver base do I need for a retaining wall?

After tamping, you must put a layer of paver base down. The height of your retaining wall dictates how many inches the depth of paver base you need. Mine needs 2, but you could need as many as 6 inches of paver base. Check with the building materials specialists who sell you your materials!May 6, 2020

How much gravel do I need for a backfill retaining 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. Compacted native soil can be used to backfill the rest of the space behind the wall.

Does a 2 foot retaining wall need drainage?

These walls need a drainage system regardless of the wall height. If there are poor draining soils such as clay behind the wall, there needs to be drainage incorporated the wall system. Clay when wet is very weak, so it is essential to provide a way for water to escape from behind the wall.Oct 11, 2020

How much base material do I need for a retaining wall?

Base material Lay a 4- to 6-inch layer of the crushed base material in the trench. Next, compact it and level it using either a hand or mechanical compactor.Jun 1, 2018

What is the best material to backfill a foundation?

Stone or gravel is the easiest material to use to ensure proper support. Don't forget, in a home with a basement, you will need eight to nine feet of fill up next to the house foundation in an attached garage. It will be difficult to make sure this is compacted properly without using stone or gravel.

How do you build a retaining wall on a sloped yard?

Steps to Follow When Building a Retaining Wall on a SlopeStep #1: Get the Trench Compact and Level. ... Step #2: Install the Wall Rock. ... Step #3: Excavate the Second Level. ... Step #4: Place the Base Course of Blocks. ... Step #5: Compact the Wall Rock Behind the Blocks. ... Step #6: Fill in the Step Up Areas.Jul 28, 2021

What is the best tool to use to lay out curved walls?

A garden hose is an excellent tool to use when laying out curved walls. Excavate the area by removing all surface vegetation and organic materials from the area. These cannot be used as backfill material. If reinforcement is needed excavate behind the wall to accommodate the design length of the geogrid.

How tall is a drain pipe?

A drain pipe is required for any reinforced wall or any wall over 4 ft. (1.2 m) tall. Place the drain pipe at the lowest possible point toward the back of the trench and vent to daylight every 50 ft. (15 m). More information on drainage and water management.

Things to Consider

Depending on the wall’s height and your location, you may need a building permit to install a retaining wall. Check your local building codes and restrictions, as well as your homeowner's association (HOA) restrictions.

Plan the Location

Using a tape measure, decide the length and the width of your retaining wall.

Dig a Trench and Level the Ground

The success of your retaining wall depends on a level base. To create a solid foundation, dig a trench for the first course of your interlocking retaining wall blocks. Make sure the ground remains even throughout.

Lay the Base

Due to soil erosion, your retaining wall should be built on a solid foundation made from gravel.

Lay the First Course of Blocks

It’s time to start laying the retaining blocks on the sturdy base you just created.

Cut End Blocks

The blocks should be staggered, so you’ll need to cut the end blocks of each even-numbered course in half. For example, the second and fourth courses should have half end blocks, while the first and third courses should have full end blocks.

Lay Additional Courses

By installing an even first course, you’ve successfully laid the groundwork for more courses. Here’s how you lay the next levels of interlocking wall blocks.

How far back should a retaining wall be?

The rule of thumb is to separate wall tiers by a distance that’s no less than twice the height of the wall below. So if the bottom wall is 4 feet tall , the wall above it should be built at least 8 feet behind it.

Who owns Blakeborough Hardscapes?

Joe Blakeborough (right) owns and operates Blakeborough Hardscapes in Prior Lake, MN, with the assistance of his younger brother, Jake (left). They run multiple crews that specialize in block and boulder retaining walls, paver projects, outdoor living spaces and other services.

Do hollow blocks need backfilling?

Also, some hollow blocks require individual backfilling, which is time consuming. These pros prefer Versa-Lok blocks, which are held together with pins rather than a lip on the bottom because pinned blocks work better on tighter curves, and the flat bottom makes them easier to stack.

Can you cut with water?

Use a gas-powered cutoff saw like this one for a smooth cut. This saw can cut with or without water. Water eliminates the dust but creates a messy slurry that can permanently stain surfaces like driveways and sidewalks. If you don’t use water, make sure the dust doesn’t blow into the house or on a neighbor’s house.

Is stone compacted as soon as it's laid in a trench?

You’ll notice the stone is almost 100 percent compacted as soon as it’s laid in the trench. The same type of stone will be used for backfilling, which also eliminates the need for hauling in multiple materials. 5 / 18. Construction Pro Tips.

Is every editorial product independently selected?

Every editorial product is independently selected, though we may be compensated or receive an affiliate commission if you buy something through our links. Ratings and prices are accurate and items are in stock as of time of publication.

Does soapstone work on wet blocks?

The downside is that soapstone doesn’t work as well on wet blocks. You can find these pencils at online retailers.

What is retaining wall?

Retaining walls have a wide variety of uses around the yard, all of which involve keeping earth from spilling off a steep slope. They’re indispensable in the creation of sunken patios, walkout basements, and any other hardscape with an abrupt separation of ground elevation. You’ll also find retaining walls in parks and public gardens, where they act as retainers for plants, statues, and decorative landscaping elements.

How to keep retaining wall from pushing outward?

They’re also widely available at most home centers. To keep the bottom row of blocks from pushing outward, bury the lowest section of a retaining wall. The general rule of thumb is to bury about one-eighth of the height of the wall.

What is buried footing?

A buried structural footing is usually required for larger retaining walls. To create this, a landscaper pours concrete below frost level (the depth to which the ground will freeze during the winter). Footings poured too shallow are prone to shifting and moving if moisture in the soil freezes and heaves.

How high should I bury a brick wall?

The general rule of thumb is to bury about one-eighth of the height of the wall. For example, if your wall will be three feet (36 inches) tall, the first course of blocks should start five inches below soil level. The gravel base should start three inches below this.

What is gravity wall?

You could also add extra strength with a “gravity wall,” which is so wide that its weight serves as a buttress against the pressure of the soil behind it. This type of wall isn’t common, however, because it requires an extensive amount of stone or concrete for construction.

What is a step back wall?

This design, known as “step-back construction,” creates a sturdy wall structure that pushes back against the lateral pressure of the soil behind it . Step-back walls can be built by anyone with a strong back and basic construction knowledge, as long as they have blocks designed for retaining wall assembly.

How much does a retaining wall cost?

A natural stone or brick retaining wall laid by a mason can cost upwards of $20 per square foot, and a poured concrete retaining wall will set you back $13 to $18 per square foot.

How do you backfill a gravel retaining wall?

Steps For How to Backfill a Retaining Wall Lay your base of compacted native soil (about three inches deep). Tamp the soil to ensure that it is secure and firm. Fill the next six to twelve inches with aggregate or gravel. Tamp the gravel or aggregate to ensure a sturdy base. •

What is the easiest retaining wall to build?

For the average do-it-yourselfer, building a retaining wall is easiest when using masonry blocks that will be stacked no taller than three feet, with no mortar binding the stones or concrete members. (For a curved wall, mark instead with a garden hose or spray paint.

What is the cheapest type of retaining wall?

The cheapest types of retaining walls are wood and concrete blocks, followed by concrete and stones or bricks. Each material has benefits and drawbacks, including strength, longevity, and attractiveness. For those who are planning on building their own retaining wall, it is vital to plan and research.

What is the best base for a retaining wall?

Due to soil erosion, your retaining wall should be built on a solid foundation made from gravel.

Do you fill hollow retaining wall blocks?

Fill in the area in front of the blocks with on-site soils. This will keep the base course blocks from shifting while filling and compacting. Fill the hollow cores of the base course and 12 in.

How do you stop a retaining wall from failing?

How to Prevent Retaining Wall Failure Drain Excess Water. The most common reason why retaining walls fail is there is no system to drain the water that has been absorbed by the soil. Reinforce the Wall. A retaining wall is put under a lot of pressure by the soil it’s holding back. Ensure Proper Compaction.

How long do you wait to backfill a retaining wall?

Some retaining walls are designed as cantilevers. These typically include reinforcement and rely on the combined strength of the concrete and reinforcement to resist bending at the base of the wall. In that case, plan to wait seven days before placing the full depth of backfill.