QA

How To Install A Retaining Wall

Can I install my own retaining wall?

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.

How deep should a base be for a retaining 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 the cheapest way to build a retaining wall?

What Is the Cheapest Type of 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.

Do you need a permit for a retaining wall?

Is a Permit Necessary? If you are considering having a retaining wall built on your property, you’re probably wondering if you will need to file for a permit. As a general rule when remodeling your home or property, a permit is usually required when additions, alterations or new construction is involved.

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.

Can you build a retaining wall on concrete?

While you can build a retaining wall on concrete, it isn’t that straightforward. If you have an existing concrete base, you cannot just build your wall on top of it. Without being secured into the concrete, your wall will slide due to the soil pressure against the wall.

What does it cost to build a retaining wall?

You’ll pay between $250 – 550 per square metre for a retaining wall in Sydney.The cost of retaining wall materials in Sydney. Retaining Wall Material Price Per Square Metre Poured Concrete $200 – 250 Treated Pine $50 – 150 Hardwood $100 – 250 Stone Veneer $110 – 150.

What do you use for drainage behind a retaining wall?

Gravel Backfill 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.

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 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.

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.

Do I need a structural engineer for a retaining wall?

In most states, retaining walls taller than four feet must be designed by or approved by a qualified, licensed professional engineer. It is important to check with and adhere to local building codes prior to design and construction.

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.

How high can you make a retaining wall?

Gravity walls can be small (under 4-feet high) or go upwards to ten feet without reinforcement. Municipalities usually require a building permit for walls taller than 4 feet.

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.

How high can a sleeper retaining wall be?

This system works for sleeper walls up to 1200mm in height; anything higher than 1200mm needs to be designed by an engineer to take account of local ground conditions and loadings.

What slope requires a retaining wall?

The wall should lean into the hill at a minimum of 1 inch for every 12 inches of height in order to maintain a safe load on the wall.

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. (300 mm) behind the block.

Can you use sand as a base for a retaining wall?

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. Be sure to use coarse builder’s sand, and tamp it down firmly to keep the sand from shifting and settling after the wall is built.

How thick should concrete retaining wall be?

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.