Retaining Wall Design for Portland Landscaping by Lee Glasscock

November 2013

Portland Landscaping: Retaining Wall DesignIf you live in the Portland, Oregon area, you should know that the soggy winter months are a great time to build a retaining wall. As summer projects fade, landscape contractors find themselves with more time on their hands—time to work on your retaining wall design, for instance. This blog covers all the basics about retaining walls, including design considerations, challenges, uses, and special considerations for retaining walls in Portland.

Retaining Walls: Why Hire an Expert

A retaining wall can be an attractive and functional feature of your landscape, especially if you have a steeply sloped area. But the construction of a retaining wall is almost never a quick, DIY process. First, there’s plenty of digging to do, in order to move soil to the proper location. Next, design expertise is needed to build a retaining wall that will hold back a whole hillside of earth while also allowing water to pass through.

In fact, the City of Portland, Oregon requires any retaining wall over four feet tall, when measured from the bottom of the footing, to have a building permit which often requires structural engineering to go along with it.  A building permit is also needed in Portland if your retaining wall supports a surcharge, or in layperson’s terms, additional weight beyond the typical load of backfill such as a road or a slope. So if you are planning your own DIY retaining wall project, it is probably best to think small.

Why Build Retaining Walls?

Retaining Wall Design: Basalt Boulder and WallrockRetaining walls make it possible to take advantage of steeply sloped areas that would otherwise be unusable. In this way, retaining walls add viable space, a valuable proposition for any homeowner. Here are a few of the potential applications for retaining walls.

Terracing. A terrace system can be created with almost any grade. Terraces are useful for footpaths and can provide additional planting or play areas.

Creating a flat area. A simple one- or two-layer stepping stone retaining wall design creates a terraced pathway. Or, if the grade isn’t too steep, retaining walls can create larger flat areas that are suitable for socializing. If the majority of your yard is comprised of a steep slope, adding a retaining wall can create the perfect place for kids to play and adults to relax.

Benches. If positioned properly, retaining walls also make great benches or seatwalls, as we call them. The entire wall can function as a seating option, or you can design a custom bench to be located at a certain spot.

Decorative plantings. Retaining walls make great planters and can be used for decorative annuals, perennials, and even some shrubs and trees, depending on the size, space, and design of the retaining wall. Potted plants can be placed along the top of a retaining wall, while climbing and draping varieties can complement a retaining wall’s verticality. When the holidays come, you can line up Jack-O-Lanterns or decorative lanterns along your retaining wall.

retaining Wall Design: Mica LedgestoneProtect property against deadly natural forces. If your property is on a hillside, or has a steep grade, you may need to build a retaining wall in order to protect your home and holdings from the forces of nature.

Manage Water Runoff. One practical purpose of retaining walls is to manage water run-off. Retaining walls help slow the flow of water as it moves downhill. In Portland, Oregon landscaping, slowing down water flow keeps polluted street water out of the nearby rivers. It is possible to combine retaining walls with rain gardens and other water management techniques.

Downhill Erosion. If water runoff is causing erosion problems, a retaining wall can help minimize this process. For instance, if your home is located at the bottom of a hill, a retaining wall can catch and hold back eroding soil before it rushes onto your property.

Sliding Hills. The hills around Portland get a lot of rain and are prone to landslides and corresponding erosion.

A retaining wall can help control the destructive forces of nature while also creating beautiful landscaping areas.

The Costs of Building a Retaining Wall

Portlan landscaping: retaining Wall DesignMany times the budget for a retaining wall project is built into the cost of a larger project. For instance, if you’re leveling a certain part of your yard, you will most likely need a retaining wall to help hold the earth in place (and keep it from sliding downhill). Also consider if any of the conditions above apply to you. If so, don’t hesitate to call Landscape East & West. We have decades of experience in retaining wall construction and design, and our experts will be able to give you a professional estimate. Here are a few of the considerations that go into a retaining wall quote.

Calculating the Costs. You can make some brief estimates yourself as long as you are able to get measurements of both the height and width of your proposed retaining wall. The costs will vary on a variety of factors, including materials, total area, excavation needs, site access, and more.

Materials. Materials are a key consideration when determining the cost of a retaining wall. Decorative poured concrete, brick and mortared stone are probably going to cost the most, while stacked stone is a mid-range option and boulders or interlocking concrete block can be a less pricey consideration. Retaining walls may also be constructed of wood in the right situation. We have a wide variety of material options for you to choose from, so as to match your design preferences to your budget.

Retaining Wall Challenges for Portland Landscaping

Landscaping Portland is a true joy. This city is a great place to garden, but keep in mind certain parts of town pose special challenges. The West Hills, for example, are known to suffer significant soil movement after storms. Because of Portland’s unique retaining wall obstacles, it’s wise to hire a geological engineer to inspect your particular situation. Or, for the sake of convenience, you can partner with a company like Landscape East & West, who maintains partnerships with local geological and structural engineers.

Retaining Wall Design: Basalt with Mortared CapIt rains. In the winter, experienced Portlanders know to expect heavy and often prolonged rains. Drainage is one of most important aspects to consider in any landscaping project, including retaining walls. French drains can be installed to help facilitate drainage and movement of water through the retaining wall system. As you can see, there’s plenty to consider in retaining wall construction; but there’s no need to stress. Allow the experts at Landscape East & West to create a structurally sound, perfectly draining, beautiful retaining wall that will match your property and make it more functional and usable.

We have plenty of a retaining wall design options to make tricky situations work. For instance, if you have an area that is between 5 and 6 feet above grade, but without a steep slope, it may be possible to install two three-foot-tall retaining walls, or three two-foot walls, or some similar combination.

If you are a Portland area resident looking for quality landscaping, including retaining wall design and construction services, contact Landscape East & West. We are fully licensed and bonded, with many years of experience designing and building beautiful, functional Portland landscape environments.

 

Outdoor Lighting Expert Lee GlasscockContributing author Lee Glasscock is a Design & Sales Associate at Landscape East & West, Portland landscaping professionals. Lee specializes in retaining wall design and has many years of experience helping Portland, Oregon residents create beautiful and functional yards.

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