Retaining Walls

Retaining Walls

CMU Block or Concrete Retaining Walls

Do I need a retaining wall? It’s a question we hear a lot here at Airtight Construction. We’ve been shaping and transforming landscaping in the San Francisco area for decades, and have become trusted leaders in the field, and that often includes retaining walls, generally constructed with either CMU (block) or reinforced concrete.

Hardscaping is an important part of any landscape plan, whether on a commercial lot or a residential backyard, and with the proper planning can turn your garden areas into a joy. Here’s everything you need to know about retaining walls and how to decide if you need one. Our professional installation team has decades of experience managing projects like this, so if you need a free quote for your project, don’t hesitate to call us.

CMU Block or Concrete Retaining Walls

What is a Retaining Wall?

Retaining walls are a key part of any landscape design. While they do look good, they also help control key aspects of the garden plan, from how water flows to preserving soil and bed integrity by holding back dirt. They can even help bolster your security at the premises. This helps you sculpt a landscape that matches your needs, even if Mother Nature isn’t naturally cooperative.

In San Francisco, retaining walls allow an attractive way to solve the challenges of sloping or unstable terrains, often making something out of a landscape nothing. It’s a common job for concrete contractors to see for this very reason. Imagine the satisfaction of crafting a constrained nook of useless soil into a warm and beautiful garden space or yard that can be enjoyed and loved. This is why we love offering these services.

Made from interlocking blocks or poured concrete, these walls work by protecting parts of the property from soil sliding out of place. This can reinforce foundations and structures, add surface area to lots, or help hold existing landscape in place.

Unlike many construction elements, we like our retaining walls to look beautiful as well as be functional, as they are a prominent part of the landscape and can affect the look and feel of a yard. That said, a smart material choice always needs to be made with function in mind. Wood, for example, cannot successfully be used in damp locations where rot and termites can reduce its lifespan. Masonry is not suited everywhere, either. Blocks may be the best option, or you may be best served with poured concrete.

A good contractor will always help you make the very best choice of materials, style, and functionality for your project, and will leave you with an aesthetically pleasing, functional product that will last for years.

Why retaining walls work

By ‘retaining’ the wedge of dirt, a well-designed retaining wall provides counter-forces that prevent gravity, lateral earth pressure, and water (hydrostatic pressure) from pulling soil downhill. That’s why poor installations often fail. Without the correct design and balance of forces, gravity always wins. This is why using an experienced contractor is key.

Some areas can install into the landscape as-is, while others may need excavation or related work.It’s also essential for drainage to be considered in the design. In some cases, you may use it to retain water, although mostly they are created to self-drain or with inbuilt drainage systems. This also cuts down on pressure on the wall, stabilizing the entire system.

While your retaining wall contractor will typically handle such matters, it’s worth knowing that walls over 4” will need to be permitted in San Francisco, which can affect price and cost. The Airtight Construction team have the experience and expertise to ensure your project is well designed and built to last, as well as correctly permitted, so you don’t have to worry..

Types of Retaining Wall

There’s 4 major types of retaining wall you can use to sculpt your outdoor space. This refers specifically to the design of the retaining area, not the look, so you generally won’t be bothered by the details.

Determining which build style of retaining wall is best for your space is typically your contractors job, as they have the experience and construction know-how to know what will work best in the space. Here’s a basic idea of how each style differs, however, and where it’s best used. Our team will work with you to find the best option for your needs as a key part of our services.

Cantilever Wall

This style uses strengthened concrete on a base slab, with a thin stem doing the actual retaining. It’s fixed to another structure, and forms something of an ‘L’ or upside-down ‘T’ shape.

It’s a difficult style of retaining wall, as it cannot support the weight other styles can. That said, it still can handle a lot of weight. It needs to be carefully engineered by a pro, and cannot have the ‘tipped forward’ look of some retaining walls. It’s often back-filled for extra support.

They are, however, a popular choice of retaining wall, often used on retail premises as they hold a large volume of dirt and are easy to custom-pour as well as light on materials. They are likely too fiddly for the average yard.

If a cantilever design is right for your project, consider adding counterforts, or keeping walls, which will make the design stronger and can reach a greater height. These consist of ‘wedges’ or ‘webs’ added to the design.

Anchored Wall

Sometimes called secured walls, it’s a design that uses steel cables or steel strips secured into the earth beyond them to leverage strength. They’re often anchored by pressurized concrete or drilling.

It’s one of the most complex wall designs, but excellent for areas where you need a small wall to do big work, or if you have high lots to look after.

Sheet Piling Wall

Another retaining wall style used in tight spaces, here you drive a slim wall directly into the slop you’re retaining.

It needs careful ‘groove’ designs to ensure it can support sufficient weight, and is best used with smaller volumes of soft dirt. If it’s needed in a larger space, it will almost always need reinforcement, but can be used in combination with secured retaining walls very successfully. They’re also a common temporary retaining wall design.

Gravity Wall

Gravity Wall

Here we lever the power of gravity through massive materials like concrete to resist stress and hold dirt. Typically we will give nature a hand through smart design tricks like a backwards lean, ensuring the wall can stand up to the test of time.

While it’s a very simple (and ancient) type of retaining wall, it’s also versatile and popular. You can use dry-stacked stone or create a neat concrete retaining wall. There’s often some trenching or excavation involved to ensure this style of wall has the longest life and can carry the heaviest loads.

Gabion Mesh Walls

These are often used for small projects or where flowing water is an issue. They consist of mesh ‘blocks’ filled with heavy material, and are constructed something similarly to gravity retaining walls, with each block carefully assembled into a strong design with good drainage.

This allows moisture to pass through easily, while still using the bulk of heavy materials to stop erosion. They only have the lifespan of the wire used in the mesh, however, as it will eventually rust. That said, they can be a cheap and pretty alternative for small backyard areas with soil issues.

Styles of Retaining Wall

Now you know a little more about what goes into designing your retaining wall, we can get to the important part- finding the right look to compliment your property.

A word on ‘Natural’ Retaining Walls

Natural retaining walls can refer to two things, and this is often an area of confusion for buyers. Any style of retaining wall- from concrete retaining walls right through to block retaining walls- can be faced with natural stone to fit a certain aesthetic. This is a popular styling choice, as it doesn’t interrupt the eye and imparts a sense of gravity and grounding to the scenery that works naturally in outdoor areas.

‘Natural’ Retaining Walls

However, as a specific type of retaining wall, what some construction companies will call natural stone retaining walls are smaller gravity walls built from the stones. These are meant for light and small projects, and are not suitable for larger areas or for heavy erosion prevention. There are circumstances in which it will not be tough enough to hold up to the demands of the job.

However, it can be used as a cheaper style of retaining wall that ‘tweaks’ the landscape, rather than a hard style, and has a lot of versatility regarding shape and location. They’re often used as semi-retaining walls, used to help divert runoff water and ensure good water management on the property. You can develop the gravity retaining wall style in areas needing more reinforcement, with dry-stacked stone or masonry to complement the look, when a stronger retaining wall is needed.

However, as a specific type of retaining wall, what some construction companies will call natural stone retaining walls are smaller gravity walls built from the stones. These are meant for light and small projects, and are not suitable for larger areas or for heavy erosion prevention. There are circumstances in which it will not be tough enough to hold up to the demands of the job.

Brick or Cinder Block Retaining Walls

More correctly, this style of masonry retaining wall is called a block retaining wall or segmented retaining wall. There is a range of interlocking-block systems available today, including paver systems, meaning these walls can curve and taper as needed.

They make a versatile and elegant choice that blends well with most properties, and the diverse range of material you can use means you’re sure to find a look you like. The wall is literally assembled from the blocks, which means it can also be staggered forward or backwards (landscape and pressure dependent) or assembled with gaps to ensure excellent drainage. The blocks in block retaining walls are often dry-stacked, so a good knowledge of design is needed to do the job right.

Brick or Cinder Block Retaining Walls

Block retaining walls are resilient and tough, while still looking great. If the color of brick or the block system does not appeal, or you’d like a clean and modern commercial look, concrete cinder blocks are very popular. Both styles are long lasting and can be faced with alternate masonry, stucco, stone, or plantings if preferred.

Poured Concrete Retaining Walls

Poured concrete retaining walls can be customized and shaped to an even higher degree than block retaining walls. This means they integrate well into almost any landscape, no matter the size and shape.It also has a clean aesthetic that is attractive to many, and can be camouflaged artfully if necessary. When correctly designed, drained, and back-filled, a concrete retaining wall is a hardy and long-lasting choice and there’s almost no project it can’t be used in.

Wood Retaining Walls

Wood Retaining Walls
Because timber is not durable in this application, wood retaining walls are rarely used. They can, however, be used with some success for residential projects, or in smaller areas, provided you are happy with the reduced lifespan and lack of tensile strength.

Custom Retaining Wall Designs

We at Airtight Construction know that no landscape is the same. Each and every project needs a personal touch that will maximize the potential of the property in the best way possible.

Our professional contractors will design, source, and create your landscaping for long life and beautiful looks, working with the landscape and installing any other features you require at the same time. Let us know what you want from your retaining wall design, and we’ll do whatever we can to make those dreams a reality. From concrete retaining walls to block retaining walls, we can do it all.

We will work with you to create the best quality project possible within your budget and property constraints. Why not get in contact with Airtight Construction today, and let us get started with your custom designed retaining walls today? Your property will thank you and you’re sure to love the results. We’re also happy to help out with any questions you may have.

Retaining Wall Plans

Building a concrete block retaining wall can help to improve the aesthetic of your building and the surrounding grounds. Yet it takes careful planning to get it right. All retaining walls, retain soil but the scale of the wall will differ from one project to the next.

Considerations Before Starting Your Block Retaining Wall

Before you start the project, you must consider several matters. These include

  • The location – make sure that you aren’t planning a block retaining wall over underground utilities. These may include sewerage lines, water supply lines, or stormwater drains.
  • The natural water drainage in the area – you don’t want to obstruct the flow of water in the area.
  • The soil – you must ensure that the soil can bear the weight of the retaining wall. You need strong, dry soil so clay is not suitable.
  • Wall design – the design of the retaining wall must be such that it reduces the pressure of the earth behind the wall. If the design of the wall cannot on its own prevent gravity from collapsing the wall, then we must reinforce the wall to prevent any chance of collapse.
  • Drainage – water is the biggest culprit when it comes to retaining wall failure. So, it is vital that the retaining wall system is properly prepared for drainage. Simple systems such as gravel backfill and water drainage holes in the block retaining walls will allow effective water drainage.

Once you have put together the plans for your walls, it’s time to choose the most suitable wall for your project. The retaining wall that best suits your property will depend on the height and ambient conditions.

Our staff can help you to plan your project. We’ll ensure that you make the best choice of concrete retaining wall to match your property and your budget.