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 deep should footings be for a retaining wall?
All footings should be a minimum of 150mm (6″) in depth, with the bottom 350 – 400mm (14-16″) below ground level on most soils. For clay soil however, thicker and deeper footings should be used.
What is the footing of a retaining wall?
One key aspect of retaining wall construction is preparing a solid footing, or foundation. The footing is usually made of poured concrete but in some situations homeowners may instead opt to simply use tamped earth or a gravel base.
Does a short retaining wall need drainage?
Although there are exceptions, most retaining walls require gravel backfill, soil compaction, pipe or toe drains, and weep holes. Together, these four features will provide adequate drainage for most designs. Only a few types of walls will not require all of them.
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.
What do you use 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 4 foot retaining wall need drainage?
The design and performance of most retaining walls are based on keeping the area behind the wall relatively dry. 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.
What retaining wall does not need drainage?
Stackable retaining block walls with gravel or sand backfills don’t typically have drainage issues, since water seeps down through the backfill and drains out between the individual blocks.
Do you need gravel behind retaining wall?
Second, a retaining wall must have properly compacted backfill. 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.
What is the cheapest way to make a retaining wall?
The cheapest type of retaining wall is poured concrete. Prices start at $4.30 per square foot for poured concrete, $5.65 for interlocking concrete block, $6.15 for pressure-treated pine, and about $11 for stone. Installation or supplies, such as drainage stone or filter fabric, are not included.
What is the cheapest wall to build?
What is the cheapest retaining wall material? Treated pine and is the least expensive material. Hardwood is more expensive than treated pine. Railway sleepers are another – slightly more expensive – option and are built to withstand ground and water contact. Concrete sleepers are more expensive.
What type of retaining wall is best?
Concrete and Masonry Retaining Walls Poured concrete is the strongest and most durable choice for retaining walls. It may also be carved and formed to look like mortared stone depending on your taste.
How do you calculate backfill on a retaining wall?
Multiply the length of the wall by the desired height, then divide this number by 81 to determine the amount of backfill gravel needed. Add the backfill amount to the base amount to determine the total cubic yards of gravel necessary for completing the wall.
How much does a retaining wall cost?
The average cost of building a retaining wall is $5,621. You’ll likely spend between $3,198 and $8,701, but some projects hit $14,000. You’ll pay $20 to $60 per square foot or $30 to $150 per linear foot on average, with large, complex builds with high-end materials costing up to $125 per square foot.
Why are drain holes an essential part of a retaining wall?
Whether built of stone, concrete or brick, a retaining wall requires good drainage. Without it, water pressure can build up behind the wall and eventually topple it. To allow underground water to seep through a mortared wall, space weep holes at 2-foot intervals along its base.
How do you calculate retaining wall?
Multiply the length of the wall (in feet) by the height of wall (also in feet) to get the square footage of the outside face of the wall. Then, multiply 1.12. This allows for having 12% of the wall’s height under the surface of the ground to give the wall more stability.
What kind of rock do you put behind a retaining wall?
Our experts prefer crushed stone for the base rather than naturally occurring gravel dug from a pit. Crushed stone is a little more expensive. However, it provides better drainage, and because of the sharper angles on the stone, it requires less compacting, and once it’s compacted, it stays that way.
Can you use pea gravel behind a retaining wall?
Pea gravel is a common landscaping material because it is easy to with and cheap. When building a retaining wall or garden border or setting fence posts, backfilling with pea gravel instead of sand, crushed limestone or other materials has benefits.
How much weight can a retaining wall hold?
Even small retaining walls have to contain enormous loads. A 4-foot-high, 15-foot-long wall could be holding back as much as 20 tons of saturated soil.
What can I do instead of a retaining wall?
Reinforced Soil Slopes. Reinforced soil slopes are a quick and easy construction style that uses a geotextile, such as polyethylene or polypropylene, to lock existing soil into place to create a reinforced mass. Natural Stone Walls. Wooden Timbers. Gabion Walls. Soil Bioengineered Walls.
How many deadmans are needed for a retaining wall?
Install one dead man every 6 to 8 feet around the entire wall. Continue building up the retaining wall, using landscaping screws to secure each timber. Cover the ground in front of the retaining wall with 2 to 4 inches of bark mulch.
Can I build a retaining wall myself?
Retaining walls can be made from wood, bricks, natural stones or concrete blocks. For DIYers, it’s best to use concrete retaining wall blocks, which can be interlocking and are heavy enough to stay in place without cement or other adhesive. Plan to build your wall after a long period without rain, when the soil is dry.