Concrete Grinding
Concrete grinding uses rotating diamond-bond tools to remove the top layer of a slab - taking off coatings, adhesives, surface laitance, or high spots to create a flat, profiled surface. Seattle Concrete grinds for surface preparation, trip hazard removal, coating removal, and polished floor finishing across residential and commercial projects in King and Snohomish counties.
Surface profile and why it matters
The International Concrete Repair Institute (ICRI) defines nine Concrete Surface Profile (CSP) levels from CSP 1 (near-smooth) to CSP 9 (scarified/shotblasted). Grinding typically produces CSP 2–4. The target profile depends on what goes on top: self-leveling underlayment requires CSP 2–3, epoxy coatings require CSP 3–4, and decorative polishing uses successive passes from CSP 2 down to a near-mirror finish. We specify the target profile before any grinding begins so the result is correct for the application - not just "flat."
Grinding process
Grinding begins with a coarse-grit metal bond tool (40-grit) to remove surface material, followed by progressively finer tools (80-grit, 120-grit, and beyond for polishing). Most floors require a minimum of two passes for surface correction. We grind wet to suppress dust when working near HVAC intakes or occupied spaces, and dry with HEPA vacuum shrouds when wet methods aren't appropriate. After grinding, a liquid densifier is applied to harden the surface before sealing or polishing.
Common grinding applications
Surface prep for epoxy or polyurethane coatings, coating and paint removal, trip hazard removal at sidewalk panel joints, high-spot correction for flooring installation, and preparation for decorative overlays or staining. Grinding can also smooth trowel ridges on new slabs that cured with surface imperfections.
Frequently asked questions
How much does concrete grinding cost in Seattle?
Concrete grinding in Seattle typically costs $1.50–$4 per square foot for basic surface prep or coating removal, and $4–$8/sq ft for a polished finish. Cost depends on slab condition, the number of passes required, and whether a densifier or sealer is applied afterward. Get a free on-site estimate before budgeting.
How long does concrete grinding take?
A standard residential or commercial concrete grinding project in Seattle takes 1–3 days depending on square footage and desired finish. Prep work - cleaning, crack patching, and masking - adds a few hours. Multiple grinding passes (coarse to fine grit) and chemical hardener application must be completed in sequence before a final polish or sealer.
Do I need a permit for concrete grinding in Seattle?
Concrete grinding of an existing slab - indoors or outdoors - does not require a permit in Seattle. It is a surface treatment, not a structural change. If the grinding is part of a broader renovation that requires a permit, those permit conditions govern the overall project.
What maintenance is needed after concrete grinding?
After grinding, apply a penetrating concrete densifier to harden the surface, then seal with a topical or penetrating sealer. Reseal every 2–4 years depending on traffic. For polished interiors, damp-mop regularly and re-polish every 3–5 years. Avoid acidic cleaners, which etch the surface and break down the sealer over time.
What types of concrete surfaces can be ground?
Concrete grinding works on garage floors, warehouse slabs, driveways, patios, sidewalks, and any flat concrete surface. It removes coatings, adhesives, paint, sealers, and surface laitance. It also levels high spots, removes trip hazards, and prepares surfaces for overlays, epoxy coatings, or decorative stains.
