Resurface or Replace Concrete? A Seattle Pre-Overlay Checklist
Last Updated:Resurfacing puts a new wearing surface on old concrete. It can make a stained, scaled, or tired driveway, patio, or set of steps look new for a fraction of the cost of tearing it out, but only if the slab underneath is sound. An overlay on a failing slab cracks and peels within a few wet seasons. This guide is a decision tool for that one question: resurface or replace? It covers the checks to run first, how the two options compare, and why overlays fail in the Pacific Northwest. For exterior projects, see our concrete resurfacing service. For basements, garages, and other indoor slabs, see interior concrete floor resurfacing.
Resurface or replace: the decision table
An overlay is typically 1/16 to 3/8 inch of polymer-modified cementitious material bonded to the existing slab. It changes the surface, not the structure, so the slab has to do the structural work.
| Condition | Resurface | Replace |
|---|---|---|
| Stains, fading, tired finish | Yes | Not needed |
| Surface scaling or light spalling | Yes, after removing loose material | If spalling is deep or widespread |
| Hairline cracks that don't move | Yes, with crack repair first | Not needed |
| Cracks that open, close, or are offset | No; they will come through the overlay | Yes, or repair the cause first |
| Sunken or tilted panels | Only after lifting | If panels are broken |
| Hollow-sounding or delaminating areas | No; the surface underneath isn't bonded | Usually |
| Exposed or rusting rebar | No | Yes |
| Wrong slope, water toward the house | No; an overlay can't change slope much | Yes, or lift if the slab is sound |
Five checks before you commit to an overlay
- Sound the slab. Tap it with a hammer or drag a chain across it. A dull, hollow sound marks delaminated areas that have to be cut out or will cause the overlay to fail.
- Check the cracks for movement. Mark the ends and widths and recheck over a few weeks of weather. Moving cracks will reflect through any overlay.
- Check slope and drainage. Resurfacing follows the existing surface. If water already runs toward the house or pools, an overlay won't fix it. Leveling or replacement will. See slab lifting and leveling for sunken panels.
- Check heights at doors, garage, and steps. Even a thin overlay raises the surface. Thresholds, garage door seals, and step risers need to stay within tolerance.
- Check moisture on interior slabs. Slabs with high moisture vapor emission can debond coatings and overlays unless that is addressed first.
How the options compare
| Option | Relative cost | Typical service life | Downtime |
|---|---|---|---|
| Resurfacing a sound slab | Mid-range, well below replacement | About 10 to 20 years when sealed and maintained | Days |
| Lift, then resurface | Mid-range | Similar, if the settlement cause is fixed | Days |
| Full replacement | Highest; includes demolition and haul-off | Decades for a well-built slab | About a week plus cure time |
Driveways and other surfaces with vehicle traffic sit at the shorter end of the overlay range. Patios and walkways tend to last longer. For a wider view of patch repairs, crack repair, and restoration, see concrete restoration: repair, resurface, or replace. For sunken slabs, read our lift-or-replace decision guide.
Where overlays fail in the Pacific Northwest
Seattle's climate is hard on overlays in a few predictable ways. Water gets into cracks and under poorly bonded edges, and repeated wet and freeze-thaw cycles pop the overlay loose. Choose a polymer-modified product with documented freeze-thaw resistance, and finish with a quality sealer. Our freeze-thaw protection guide explains why. Surface prep is the other common failure point. Overlays need clean, profiled, dry concrete, which can be hard to get in a damp season, so application should wait for a dry stretch. Shaded slabs that stay damp, grow moss, or collect needles also need extra attention to cleaning before and after.
Exterior vs. interior resurfacing
Exterior resurfacing on driveways, patios, steps, and walkways favors textured finishes for traction: broom, knockdown, or stamped overlays with anti-slip sealer. Interior resurfacing on basements, garages, and shops can use smoother microtoppings, stained overlays, or polished systems, because traction in rain isn't the limiting factor. Moisture from below is.
- Broom-finish overlay: the most economical exterior option; restores grip on driveways and walks.
- Spray-down (knockdown) texture: a stippled, slip-resistant finish often used on patios and pool decks.
- Stamped overlay: a thicker overlay textured to look like stone, slate, or brick; seal it with anti-slip additive outdoors.
- Microtopping: a very thin, smooth coat best suited to interiors or covered patios.
The interior side is covered on our floor resurfacing page. To have a slab assessed, call Seattle Concrete at (206) 552-9998.
Frequently asked questions
What is concrete resurfacing?
Concrete resurfacing is the application of a thin polymer-modified cementitious overlay, typically 1/16 to 3/8 inch, over an existing slab. It renews a worn, stained, or scaled surface and can be broomed, stamped, or stained, without removing the concrete underneath.
When is resurfacing the right choice instead of replacement?
Resurfacing works when the slab is structurally sound: no moving or offset cracks, no hollow or delaminated areas, no failed base, and acceptable slope. If the problem is only the surface, such as stains, fading, or light scaling, an overlay is usually the better value.
How do I know if my concrete is too damaged to resurface?
Warning signs include cracks that move or are offset, hollow-sounding areas when tapped, exposed or rusting rebar, broken or sunken panels, and water draining toward the house. Any of these means the overlay is likely to fail, so repair, lifting, or replacement should come first.
How long does resurfaced concrete last in the Pacific Northwest?
A properly installed and sealed overlay typically lasts about 10 to 20 years in Seattle conditions. Driveways and other surfaces with vehicle traffic sit at the shorter end, and patios and walkways at the longer end. Resealing on schedule extends the finish.
Can I resurface a cracked slab?
Hairline cracks that don't move can be repaired and covered by the overlay system. Wide, offset, or moving cracks usually come back through the overlay, so the cause has to be fixed first. If the slab is badly broken, replacement is the more durable option.
