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Choosing the Right Materials for Retaining Walls in Snohomish County

Retaining walls are an essential landscaping element for many Snohomish County properties. A retaining wall holds back soil on slopes and elevations to prevent erosion. Retaining walls can be functional or add aesthetic value to outdoor spaces. With the right materials, they can last for decades with minimal maintenance.

Snohomish County’s climate and soil composition are important factors in choosing retaining wall materials. The area experiences a significant amount of rainfall annually, with wet winters and occasional freezing temperatures. The soil tends to have high clay content in many areas of the county. These conditions require using durable materials that can withstand moisture, shifting soil, and freeze-thaw cycles.

In this article, we will recommend the best materials for DIY and professionally built retaining walls in Snohomish County. The ideal materials will be long-lasting, stable, and well-suited for the regional climate and soil. We will compare material options like concrete, stone, timber, and blocks. With the right information, you can construct stable, low-maintenance retaining walls that will stand the test of time. Let’s explore the optimal materials for your retaining wall project in Snohomish County.

To simplify, We recommend Concrete for your retaining wall because of its 50+ year lifespan plus, it can be molded into any shape.

Table of Contents

Retaining Wall Material Options

Concrete Retaining Walls

Benefits

  • Extremely strong and durable
  • Long lifespan of 50+ years
  • Can be molded into any shape
  • Versatile design options
  • withstands soil pressure

Drawbacks

  • Expensive compared to other options
  • Requires professional installation
  • Not a natural appearance
  • can crack over time
  • not a natural look

Tips for Installation

  • Use steel reinforcement
  • Create slight slope for drainage
  • Allow concrete to cure properly
  • Have contractor install weep holes

Brands

 
Concrete is a highly durable and versatile material for retaining walls. When properly mixed and reinforced, concrete can last for decades with minimal maintenance. Concrete walls can be molded and shaped as desired during pouring. Concrete’s high compressive strength withstands soil pressure well. However, concrete is one of the more expensive options for retaining walls. Pouring concrete requires professional expertise to get it perfectly level and properly cure. Concrete walls should have weep holes to allow moisture to escape. Overall, concrete is best left to professional installation but results in strong, long-lasting retaining walls.

Stone Retaining Walls

Benefits

  • Very long-lasting, 30-100 year lifespan
  • Natural, rustic aesthetic
  • Granite and basalt are dense and weather-resistant

Drawbacks

  • Expensive
  • Irregular shapes can shift
  • Professional installation recommended

Tips for Installation

  • Construct compacted gravel base
  • Use geogrid soil reinforcement
  • Stagger stones in heart bond pattern
  • Use large boulders on bottom rows
 Brands
  • BasaltCO
  • Coldspring
  • Rock Solid Stoneworks
 
 
Stone retaining walls provide a classic, natural look. Granite and basalt are excellent choices as they are very dense rocks that resist weathering. A stone wall must have a solid footer and be carefully stacked, interlocking the irregular shapes. Using a high-quality construction adhesive between layers gives added stability. For drainage, include gravel backfill behind the wall. Stone boulders can also be used but require heavy equipment to move into place. Stone walls are challenging for DIY due to the expertise needed to engineer them properly. Hiring a professional ensures correct base preparation, weight distribution, and techniques like using geogrid soil reinforcement. Though expensive, a well-built stone retaining wall can add beauty and function for generations.

Timber Retaining Walls

Benefits

  • Affordable compared to stone or concrete
  • Relatively easy for DIY installation
  • Variety of styles to complement landscaping
  • lighter than stone or concrete

Drawbacks

  • Less durable than stone/concrete, 10-20 year lifespan
  • Susceptible to rotting without proper drainage
  • Not as strong

Tips for Installation

  • Overlap joints between timbers
  • Use thick landscape ties or 6×6 posts
  • Backfill with gravel, not soil
  • Apply water-repellent sealant annually
 Brands
  • YellaWood
  • TimberTech
  • Gorilla-Wood
 
 
For DIY-friendly retaining walls, pressure-treated timber is a top choice. Cedar and redwood are naturally rot-resistant woods suitable for retaining walls. Using large landscape ties or 6×6 posts allows building tall, sturdy walls. Overlap pieces in each row and use rebar or landscape spikes to pin them together. Backfill with gravel, not soil, to improve drainage. Allow a 1-2 inch gap between timbers for drainage and use a splash block at the bottom. Apply a water-repellent sealant annually. Timber walls blend nicely into landscapes. The main drawbacks are eventual rotting, and inability to hold significant weight like concrete or stone. Overall, timber retaining walls are affordable, easy to build for DIYers, but require more maintenance over time.

Interlocking Block Retaining Walls

Benefits

  • Easy DIY project with little experience needed
  • Many style and color options
  • Affordable medium-cost option

Drawbacks

  • Can shift if base not properly prepared
  • Durability limited to 20-30 years
  • Lower weight bearing capacity

Tips for Installation

  • Compact and level base gravel
  • Include drain tile behind wall
  • Follow manufacturer instructions
  • Use grid reinforcement every 1-2 rows
Brands
  • Allan Block
  • Anchor
  • Europa
 
Overall, concrete and stone are strongest but require hiring a professional. Timber and blocks are great options for DIYers to tackle. Consider costs, aesthetics, and your project needs – a landscape designer can provide expertise.
 
 For prices on blocks they typically range from $1 to $3 each according to angie.com 

 

 
Interlocking blocks make retaining wall construction simple, even for beginners. Many types, like Allan Blocks, Lego blocks, and keystone blocks, are available. Check manufacturer specifications for weight bearing capacity and installation instructions. Prepare a compacted gravel base then stack blocks, setting them back 1⁄2 inch per row. Fill gaps between blocks with gravel, not soil. Use grid or lattice reinforcement every 1-2 rows, especially with higher walls. Block walls can be topped with capstones or use coping designed to match the blocks. Block retaining walls allow flexible design options. However, drainage issues can cause leaning or collapse, so pay close attention to backfilling properly. In general, interlocking blocks are a great medium-cost, low-maintenance solution for DIY retaining walls.

Conclusion

Best Materials for Snohomish County

The best retaining wall materials for Snohomish County are those that can withstand the wet climate and shifting soils. Concrete and natural stone are very durable options, though expensive. For more affordable DIY projects, pressure-treated timber and interlocking blocks are suitable materials.

Key Considerations

When selecting retaining wall materials, consider the climate, soil conditions, project goals, and budget. Opt for long-lasting, stable materials tailored to the region. Proper drainage and base preparation also help create sturdy walls.

Seek Professional Guidance

Consult a qualified landscape designer to evaluate your property and provide material recommendations. They can ensure your retaining wall is optimally designed for Snohomish County’s conditions.

Contact the Experts

For residents seeking a beautifully designed, expertly constructed retaining wall, contact Ivan’s Landscape & Construction. Their experienced team specializes in creating customized retaining walls to enhance properties throughout Snohomish County. Here is our Retaining Wall & Rockery Service Page

Frequently Asked Questions

What is the most cost-effective material for a retaining wall?

For DIY projects, pressure-treated timber and interlocking blocks are the most budget-friendly options. They offer an affordable way to build smaller retaining walls.

How long should a properly built retaining wall last?

With the right materials and construction, a retaining wall should last 30-50 years or more. Concrete, stone, and high-quality block walls have the greatest longevity when properly installed.

What’s the maximum height I can build a DIY retaining wall?

It’s recommended to keep DIY retaining walls under 4 feet tall. Anything higher is difficult to construct safely without appropriate engineering. Consult a professional for walls above 4 feet.

Should backfill material be gravel or soil?

Always use gravel, not soil, as backfill behind a retaining wall for drainage. The gravel space also allows for natural shifting over time without compromising the structure.

How much space is needed behind a wall for backfill gravel?

Generally allow 6-12 inches between the wall and soil for gravel backfill. The amount required depends on the wall height and soil type.

Can I build a curved retaining wall?

Yes, materials like concrete, blocks, and timber can be used to build curved retaining walls. This requires special planning, equipment, and techniques best done by professionals.