6 Types of Materials That Could Make or Break Retaining Wall Projects

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As the weather warms, thoughts turn to beautifying outdoor spaces with signature landscape elements like retaining walls.

There’s no shortage of materials that can be used to build a retaining wall, but among the most popular is stone. However, simply choosing stone over other materials like timber or gabion isn’t the only decision landscape architects, homeowners and contractors face. Neither is price. Identifying and using elements with properties that align with the climate and a myriad of other factors unique to a specific retaining wall project will help ensure desired results are achieved and maintained for a lifetime.

To help you make an informed decision, let’s explore six types of materials widely used for retaining walls:

1. Poured Concrete

Strong and versatile, the sleek aesthetics of poured concrete are at home in modern landscapes, be they small residential retaining walls or massive commercial structures like those found along freeways. Largely unadorned, poured concrete is assumed to be budget-friendly and simple to construct; however, both are misperceptions. The skill and materials required to construct the necessary pouring forms, footings and rebar skeletons — not to mention handle the finicky nature of poured concrete — can quickly drive costs up. Poured concrete also has a tendency to absorb moisture, which can contribute to surface damage, cracking and premature structural failures.

2. Concrete Block

Concrete block is a longtime favorite for retaining wall construction in a number of settings including midcentury architecture, due mainly to the easy-to-stack design, wide availability and low cost. To capitalize on these attractive characteristics, Standard Concrete Block (CMU) offerings have evolved from the very familiar “cinder block” structure — 8" x 8" x 16" with two identical openings — to include a textured, precast split face block, entire systems designed to mimic the look of natural stone, and a wealth of color options for custom dying.

However, there are considerable drawbacks to consider beyond the limitations of precast materials like cracking, crazing and staining. The two most prominent both relate to a lack of wall footing. Since a solid structure doesn’t underpin a concrete block wall, construction is limited to a maximum height of four feet, and it may lose strength and structural integrity over time. Additionally, concrete blocks are susceptible to the adverse effects of salt deicers — including cracking and crazing. Salt spray from snow plows and the use of deicers alongside concrete block retaining walls can lead to deterioration and should make those in colder climates think twice before choosing the material.

3. Brick

Among the most durable materials for retaining walls, brick complements a host of residential and commercial buildings. It’s important to note that brick retaining walls are rarely solid brick, usually incorporating concrete masonry units or steel and grout inserts upon which brick or thin brick veneers are placed. Despite the labor intensiveness, lack of color variety and its need for special drainage, the advantages of using brick — eco-friendliness, low maintenance, weather and fire resistance, durability — outweigh the downsides and justify a relatively steep cost per square foot.

4. Stone Veneer

A combination of luxury and versatility, stone veneer lets you call the shots in terms of retaining wall height, thickness, texture and pattern. Meant to encase solid core walls like those made of concrete masonry units to provide visual appeal and protection, don’t write off stone veneer as merely decorative. It is an incredibly tough yet lightweight natural material that can withstand harsh elements with minimal effect.

Making the most of the natural, custom appearance of stone veneer isn’t easily accomplished. It requires the experienced eye and design talents of a landscape architect or contractor who can seamlessly match individual stone veneer pieces to existing architecture (as in this transformation of a house into an estate), which is ultimately a worthy investment for this high end material.

5. Boulder

Naturally occurring, unquarried boulders are easily the oldest of retaining wall materials, used for hundreds of years to provide function and fashion in colonial, country and English-style gardens. There’s no fussiness to a boulder wall. It is  intentionally rustic and generally an easy construction, boulder weight and size notwithstanding.

As you might expect, a boulder wall isn’t intended for small spaces or for high wall construction as it will serve to dwarf and crowd other structures. Plus, boulder walls are limited in design — “what you see is what you get” — and are prone to water accumulation that can destroy interior wall integrity over time. Boulders are widely available, but you can expect to rack up a substantial transportation bill for these multi-ton building elements.

6. Natural Stone

As durable and impenetrable as boulders, natural stone like Type III dolomitic limestone is far more versatile in terms of size, pattern, texture and color — design latitude that helps natural stone retaining walls fit effortlessly into any setting. While a natural stone wall can be constructed without the aid of mortar or other connecting materials, the sheer weight of some of the stones and the “puzzle piecing” required to make certain patterns work makes construction best left to experienced landscape architects, contractors or stone craftsmen. Quarried from deep within the earth, natural stone is considered a pristine, unparalleled building material and is priced accordingly.

Retaining walls add beauty and value to residential and commercial properties, especially when constructed from materials that align with the design, environment and potential limitations of the surroundings. To fully appreciate the quality and possibilities of Type III dolomitic limestone, request samples today. It’s easy and it’s free — simply click the button below to get started.

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