Retaining walls are an essential landscape feature used to hold back soil on slopes or around foundations. However, building a retaining wall can be a significant investment. Costs vary greatly depending on the design, materials and size of your wall.
In this comprehensive guide, we’ll discuss all the factors that impact retaining wall costs so you can budget accurately for your project in Snohomish County.
Please remember these can differ depending on the Retaining Wall Company or if you plan on doing DYI the price may very by where you buy the material
Key Factors That Impact Retaining Wall Costs
Several important considerations affect the overall expense of building a retaining wall:
Materials
The building material you choose largely determines the cost. Here are some typical per square foot material costs:
- Wood – $15 to $45
- Concrete – $20 to $60
- Block – $10 to $50
- Stone – $25 to $80
Wood is generally the most economical choice. Concrete and block walls have a longer lifespan but require more skill to construct. Natural stone walls are the most expensive but provide a classic, elegant look.
Wall Height
The taller the wall, the more material and engineering required. Short walls under 3 feet cost $5 to $10 per square foot. Tall walls over 6 feet average between $25 to $50 per square foot.
Wall Length
Longer walls require more materials and manhours to build. Per square foot costs generally decrease slightly for longer walls since mobilization fees get spread across more work.
Excavation
Excavating and preparing the retaining wall site for construction can cost $3 to $12 per square foot depending on access and soil conditions. Difficult sites with uncontrolled fill or large boulders often have high excavation costs.
Site Accessibility
Ease of access impacts labor rates and material delivery fees. Hard to reach sites may require specialized equipment and risk premiums to operate in tight spaces. This can add 20% or more to the final costs.
Labor
Skilled retaining wall builders charge $50 to more than $100 per hour. Basic wood or block walls require less expertise than poured concrete or stone walls. Factor in higher rates for certified installers of proprietary wall systems.
Design Complexity
A simple vertical wall with no curves or patterns is the most affordable option. Multi-tiered walls, corners and curves add engineering and labor costs. Some materials like stone and block have greater design flexibility than wood or concrete.
Drainage
Retaining walls may need drainage systems behind the wall to prevent hydrostatic pressure and erosion. Perforated drainage pipes, gravel backfill and weep holes help drain excess moisture and add $2 to $6 per square foot.
Cost Ranges for Common Retaining Wall Types
To give you a better idea of real world retaining wall costs, here are typical price ranges for some of the most popular wall choices in Snohomish County:
Wood Retaining Walls
- Pine or cedar timber walls – $15 to $40 per square foot
- Recycled wood block walls – $20 to $45 per square foot
Wood is cost effective for short, simple walls up to 4 feet tall. Requires backfill and drainage materials. Prone to rotting over time.
Concrete Retaining Walls
- Poured concrete – $30 to $60 per square foot
- Pre-cast concrete systems – $25 to $50 per square foot
Concrete offers tremendous strength and design flexibility. High labor costs for forming and pouring concrete on site. Pre-cast systems are quicker to install.
Block Retaining Walls
- Basic rectangular blocks – $15 to $30 per square foot
- Interlocking blocks – $20 to $50 per square foot
Block walls provide an engineered solution. Straight walls with basic blocks are affordable. Interlocking systems allow curves, corners and height but cost more.
Proprietary Wall Systems
- Modular block systems – $30 to $70 per square foot
- Pre-cast panel systems – $40 to $80 per square foot
Engineered branded wall systems are pricier but straightforward to install. The integrated design and components simplify the construction process.
Natural Stone Retaining Walls
- Dry stack boulder wall – $25 to $50 per square foot
- Mortared stone wall – $50 to $80 per square foot
Stone walls provide a classic aesthetic but require specialized labor and heavy equipment to construct. Mortared walls with hand-fit stones are more expensive than dry stack.
Key Considerations When Budgeting
To arrive at an accurate retaining wall budget, keep the following factors in mind:
- Get bids from multiple contractors to compare rates.
- Account for long-term maintenance. Pressure treated wood or concrete will last much longer than natural timber.
- Factor in permitting fees based on your county or city regulations.
- Include demolition and removal of any existing wall or obstacles.
- Excavation, grading, drainage installation, backfill materials and compaction can add substantially to the overall costs.
- Consider decorative upgrades like caps, lighting or plantings that increase visual appeal.
Also be sure to get a detailed site evaluation from contractors to uncover any unknowns or challenges with the site. Consider a geotechnical analysis for walls higher than 4 feet.
Saving on Your Retaining Wall Project
If your budget is tight, here are some ways to reduce retaining wall costs:
- Opt for a shorter height if possible. Walls under 3 feet high can save you 50% or more compared to taller walls.
- Use readily available, affordable materials like rectangular masonry blocks rather than pre-cast systems.
- Stick to a simple straight or slightly curved wall design. Corners, tiers and patterns add considerably to costs.
- Complete demolition, excavation, backfill installation and site prep on your own rather than hiring it out.
- Look for recycled material options like used block, timber or railroad ties to save on materials.
- Consider a terraced slope with two shorter retaining walls rather than one taller one.
Retaining walls over 4 feet high often require extensive drainage and engineering. It’s usually more economical to build two smaller retaining walls spaced several feet apart rather than one massive wall.
Conclusion
While retaining walls require a significant upfront investment, a well-built wall can last for decades and add valuable functionality and aesthetics to your landscape. Carefully weigh the options to find the right materials and design for your site conditions and budget.
We hope this comprehensive guide gives you a better understanding of the factors that influence retaining wall costs. Be sure to get multiple estimates before starting your project. With careful planning and budgeting, you can build the retaining wall of your dreams!
Looking for a Professional Retaining Wall Expert? Check us out at Ivan’s Landscape & Construction or contact us
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Frequently Asked Questions About Retaining Wall Costs
What factors affect the cost of a retaining wall?
The main factors affecting retaining wall costs are the materials, size (height and length), design complexity, excavation needs, site accessibility, labor, and drainage requirements.
How much do materials impact the price?
Material prices range from $15-45 per square foot for wood, $20-60 for concrete, $10-50 for block, and $25-80 for natural stone. Wood is the most economical while stone is the most expensive.
Does wall height increase the cost?
Yes, taller walls require more materials, engineering, and labor. Short walls under 3 feet are $5-10 per square foot while walls over 6 feet run $25-50 per square foot.
How does wall length impact price?
Longer walls use more materials so costs are a bit lower per square foot. However, length does not significantly affect the installation pricing.
How much does site accessibility increase costs?
Difficult access for delivery or buildout can add 20% or more to costs due to specialized equipment needs and risk premiums. Easy access reduces labor rates.
When does a retaining wall need drainage?
Drainage is necessary to prevent hydrostatic pressure buildup. This adds $2-6 per square foot for drainage gravel, pipes, and weep holes. Proper grading is also essential.
What is the typical price range for concrete, block, or stone walls?
- Concrete: $20-$60 per square foot
- Block: $10-$50 per square foot
- Natural stone: $25-$80 per square foot
How can I reduce the cost of my retaining wall?
Choose a shorter height, opt for basic rectangular masonry blocks, use readily available materials, go for a simple straight wall design, and complete prep work like excavation yourself.
