A concrete slab is one of the most practical investments you can make in your Bellingham property. Whether you need a garage floor, shed pad, RV parking area, or workshop slab, concrete provides a durable, level surface that stands up to decades of Whatcom County weather. But understanding the true cost — from site preparation through finishing — helps you budget accurately and avoid surprises.
As slab installation specialists serving Bellingham and the surrounding communities of Ferndale, Lynden, Blaine, and Birch Bay, we pour hundreds of slabs each year. This guide breaks down real-world costs by slab type so you can plan your project with confidence.
What Determines Concrete Slab Cost?
Before diving into specific slab types, it's important to understand the factors that affect pricing in our region. Concrete slab costs in Bellingham are influenced by several variables that can cause significant price variation between projects.
Site Preparation
The ground beneath your slab matters as much as the slab itself — arguably more so in Whatcom County, where our glacial till soil and high rainfall create challenging conditions. Site preparation includes:
- Excavation: Removing topsoil, organic material, and any unstable soil down to a solid base. Bellingham's glacial till is generally stable once you get below the topsoil layer, but depths vary. Typical excavation depth: 8-12 inches. Cost: $2-$5 per square foot
- Grading: Establishing proper slope for drainage. Every slab needs a minimum 1-2% slope away from structures. In hilly neighborhoods like South Hill, Alabama Hill, and Happy Valley, grading can be more complex. Cost: $1-$3 per square foot
- Base material: A compacted gravel base (typically 4-6 inches of crushed rock) provides drainage and a stable platform. This is non-negotiable in our climate — skipping the gravel base is the single most common cause of slab failure in Whatcom County. Cost: $1.50-$3 per square foot
- Soil removal: Hauling away excavated material. Cost: $300-$800 per project depending on volume and access
Concrete Specifications
Standard residential concrete in Bellingham is a 4,000 PSI mix, which provides excellent strength for most applications. Concrete is currently priced at approximately $140-$170 per cubic yard delivered in Whatcom County. A 4-inch-thick slab uses approximately 1.23 cubic yards per 100 square feet. Air-entrained concrete is standard in our region to resist freeze-thaw damage — never accept non-air-entrained concrete for exterior slabs in Bellingham.
Reinforcement
Reinforcement prevents cracking and holds the slab together if cracks do develop. Options include:
- Wire mesh (6x6 W1.4/W1.4): The minimum standard for residential slabs. Cost: $0.50-$0.75 per square foot
- Rebar (#3 or #4 bars on 18-24" centers): Stronger than wire mesh, recommended for garage floors and any slab supporting heavy loads. Cost: $1-$2 per square foot
- Fiber reinforcement: Synthetic or steel fibers mixed into the concrete. Good supplementary reinforcement but not a substitute for rebar in structural applications. Cost: $0.50-$1 per square foot
Garage Slab Costs
Garage slabs are the most common slab installation project we handle in Bellingham, and they require more engineering than simpler pads due to the loads they support and their connection to the building structure.
Standard Two-Car Garage (20' x 24' = 480 sq ft)
- Slab thickness: 4 inches minimum, 6 inches at thickened edges and under bearing walls
- Reinforcement: #4 rebar on 18-inch centers both directions, or #3 rebar on 12-inch centers
- Base: 6 inches of compacted crushed rock over compacted subgrade
- Vapor barrier: 10-mil polyethylene under the slab (essential in Bellingham's climate to prevent moisture migration up through the concrete)
- Control joints: Saw-cut at 10-foot maximum spacing to control crack locations
Cost breakdown for a standard two-car garage slab:
- Site preparation and excavation: $1,200-$2,000
- Gravel base (delivered and compacted): $800-$1,200
- Formwork: $600-$1,000
- Vapor barrier: $200-$350
- Rebar and reinforcement: $500-$900
- Concrete (approximately 6.5 cubic yards): $900-$1,100
- Labor (pour, finish, cure): $2,000-$3,500
- Control joint cutting: $200-$400
- Total: $6,400-$10,450 ($13-$22 per square foot)
For homeowners in Bellingham neighborhoods like Cordata, Barkley Village, and Edgemoor where garage construction is common, budget approximately $8,000-$10,000 for a standard two-car garage slab with proper preparation.
Single-Car Garage (12' x 24' = 288 sq ft)
A single-car garage slab uses the same specifications but less material. Typical cost: $4,500-$7,000 ($16-$24 per square foot). The higher per-square-foot cost reflects the fixed mobilization and setup expenses that don't scale linearly with size.
Shed Pad Costs
Shed pads are simpler than garage slabs because they support lighter loads and typically don't need to meet building code requirements for habitable structures. However, in Bellingham's climate, proper preparation is still essential to prevent settling and cracking.
Standard Shed Pad (10' x 12' = 120 sq ft)
- Slab thickness: 4 inches
- Reinforcement: Wire mesh or #3 rebar on 24-inch centers
- Base: 4 inches of compacted crushed rock
- Vapor barrier: Optional but recommended to prevent moisture wicking
Cost breakdown:
- Site preparation: $400-$800
- Gravel base: $200-$400
- Formwork: $200-$400
- Reinforcement: $100-$200
- Concrete (approximately 1.5 cubic yards): $210-$255
- Labor: $800-$1,500
- Total: $1,910-$3,555 ($16-$30 per square foot)
For a 10x12 shed pad in Bellingham, budget approximately $2,500-$3,500. Larger shed pads (12x16 or 12x20) run $3,500-$5,500. We install shed pads throughout Whatcom County, from rural properties in Everson and Sumas to suburban lots in Ferndale and Lynden.
RV Pad Costs
RV pads require special attention because of the concentrated weight of recreational vehicles. A loaded Class A motorhome can weigh 30,000+ pounds, and that weight is concentrated on tires that create significant point loads. Proper design prevents the cracking and settling that plagues undersized RV pads.
Standard RV Pad (12' x 40' = 480 sq ft)
- Slab thickness: 5-6 inches (thicker than standard slabs due to the heavy point loads from RV tires)
- Reinforcement: #4 rebar on 12-inch centers both directions
- Base: 6 inches of compacted crushed rock, with additional depth if subsoil is soft
- Slope: 1-2% for drainage — critical to prevent water pooling under your RV during Bellingham's wet season
Cost breakdown:
- Site preparation and excavation: $1,500-$2,500
- Gravel base: $800-$1,400
- Formwork: $700-$1,200
- Rebar reinforcement: $700-$1,200
- Concrete (approximately 9-10 cubic yards at 5" thick): $1,260-$1,700
- Labor: $2,500-$4,000
- Control joints: $300-$500
- Total: $7,760-$12,500 ($16-$26 per square foot)
Budget approximately $9,000-$12,000 for a properly built RV pad in Bellingham. Many homeowners in neighborhoods like Silver Beach, Birchwood, and the Geneva area add RV pads to accommodate vehicles that don't fit in standard driveways. Some also include a connecting driveway apron for an additional $2,000-$4,000.
Extended RV Pad with Utility Hookups
If you plan to use your RV pad for extended stays or guest accommodation, adding utility hookups during slab installation is significantly cheaper than retrofitting later. Budget an additional $1,500-$3,000 for electrical conduit, water supply, and waste connections cast into the slab. Note that utility hookups require separate permits in both the City of Bellingham and Whatcom County.
Workshop and Hobby Slab Costs
Workshop floors need to be flat, durable, and resistant to oil, chemicals, and heavy equipment. Many homeowners in Bellingham invest in workshop slabs for woodworking shops, auto repair, metalworking, and art studios.
Standard Workshop Slab (24' x 30' = 720 sq ft)
- Slab thickness: 5-6 inches
- Reinforcement: #4 rebar on 16-inch centers both directions
- Finish: Hard trowel for smooth surface, or broom finish for grip. Many workshop owners opt for a burnished finish that resists staining
- Optional: Floor drain (required if vehicle work is planned), radiant heat tubing ($3-$5 per square foot additional)
Cost breakdown:
- Site preparation: $2,000-$3,500
- Gravel base: $1,200-$2,000
- Formwork: $900-$1,500
- Vapor barrier: $300-$500
- Rebar: $1,000-$1,800
- Concrete (approximately 13-16 cubic yards): $1,820-$2,720
- Labor: $3,500-$6,000
- Control joints: $400-$600
- Total: $11,120-$18,620 ($15-$26 per square foot)
For a quality workshop slab in Bellingham, budget $13,000-$18,000 without radiant heating. Adding in-slab radiant heat increases the cost by approximately $2,200-$3,600 for a slab this size, but it's a worthwhile investment if you plan to spend significant time in the workshop during our cool, damp winters.
Factors That Increase Costs in Whatcom County
Several local factors can push costs above the ranges listed above:
- Difficult access: If the concrete truck can't reach the pour site directly, a concrete pump may be needed. Pump truck rental adds $800-$1,500 to the project. Properties on steep lots in South Hill and Sehome frequently require pumping
- Rock removal: Some areas of Bellingham have shallow bedrock or large glacial boulders. If excavation encounters rock, removal costs $500-$2,000+ depending on volume
- Demolition of existing concrete: If you're replacing an old slab, concrete removal adds $3-$6 per square foot for demolition and haul-away
- Slope correction: Hillside properties may require retaining elements or stepped slabs. Budget an additional 20-40% for sloped sites
- Wet season work: While we pour concrete year-round in Bellingham, winter pours (November through March) may require heated enclosures and hot-water concrete mixes to ensure proper curing at temperatures below 40°F. This can add $500-$1,500 to the project
- Permit requirements: Garage slabs and structures over certain sizes require building permits in both Bellingham and unincorporated Whatcom County. Permit costs typically run $200-$500
Ways to Reduce Slab Costs
While you should never cut corners on base preparation or reinforcement, there are legitimate ways to reduce your slab cost:
- Schedule during the dry season: Spring and early fall (May-June, September-October) are the ideal pour windows in Bellingham. Scheduling during these months avoids wet-season surcharges and provides the best curing conditions
- Combine projects: If you need multiple slabs (garage pad plus shed pad, for example), pouring them in the same mobilization saves $1,000-$2,000 in setup costs
- Handle site prep yourself: If you can excavate, grade, and compact the base material yourself to specification, you can save $1,500-$3,000. However, if the base isn't properly prepared, you'll spend far more on repairs down the road
- Choose standard finishes: A broom finish is $2-$4 per square foot cheaper than stamped or decorative finishes. For utility slabs, standard finishes perform identically
- Right-size your project: A slab that's 10% larger than needed costs 10% more. Measure your actual requirements carefully before specifying dimensions
Longevity and Maintenance
A properly installed concrete slab in Bellingham should last 30-50 years with minimal maintenance. To maximize lifespan in our climate:
- Seal the surface within 30 days of pouring: A quality penetrating sealer ($1-$2 per square foot) protects against moisture infiltration and freeze-thaw damage
- Reseal every 3-5 years: Our rainfall demands more frequent sealing and maintenance than drier climates
- Keep edges clear: Prevent soil from building up against slab edges, which traps moisture and promotes edge deterioration
- Address cracks early: Seal any cracks that develop before winter to prevent water infiltration and freeze-thaw damage
Investing in a quality concrete slab pays dividends for decades. Whether you need a garage floor in Cordata, a shed pad in Lynden, or an RV pad in Birch Bay, proper specifications and professional installation ensure your slab performs as expected through every Bellingham winter.
Ready to get started? Contact us today for a free estimate — we serve all of Bellingham and Whatcom County.