Mechanical preparation has a measurable purpose
Mechanical preparation creates the profile required by the proposed coating, not just visible scratches. The Sikafloor-515 data sheet is one example requiring contaminant removal and mechanical profiling. Different systems have different requirements; ask for the instructions that apply to your job.
Can a peeling epoxy garage floor be recoated?
Yes, after removing failing material and identifying why it lost adhesion. Coating over loose paint or resin leaves the new work attached to a failing layer. A sound compatible coating may be a recoat candidate after manufacturer-approved preparation; widespread failure may require removal to prepared concrete.
The Rust-Oleum EPOXYSHIELD instructions distinguish sound previous coatings from loose or peeling material and exclude moisture-problem floors from that product’s intended conditions. They support checking the substrate and existing coating before recoating, not assuming all epoxy has the same limits.
- Separate coating wear or color change from loss of adhesion.
- Ask whether the old film, contamination or weak concrete is the failure surface.
- Include removal method, disposal, exposed-slab assessment and any additional repairs in the scope.
- Confirm preparation and compatibility if any old coating remains.
Can cracked or pitted concrete be repaired before coating?
Localized surface damage can often be repaired when the surrounding concrete is sound. Pitting means small surface losses; spalling is flaking or broken concrete. Remove weak material and select a compatible repair before applying the coating. Widespread deterioration or movement needs a different assessment.
The Rust-Oleum Concrete Patch & Repair sheet describes a repair material for cracks and damaged concrete. Its preparation and coating-readiness requirements are product-specific. Repairing the surface does not resolve settlement, ongoing slab movement or drainage.
| Condition | Possible approach | What to confirm |
|---|---|---|
| Stable crack | Compatible crack repair before coating | Preparation, depth, finish appearance and whether movement may recur. |
| Moving crack or movement joint | Preserve or accommodate movement; investigate the cause | No promise that a rigid fill or decorative coating will stop movement. |
| Localized pitting or spalled edge | Remove weak material and rebuild with a compatible repair | Repair area, depth, material, cure and readiness for coating. |
| Widespread weak or deteriorating surface | Assess the slab before choosing coating or resurfacing | Soundness and whether repair leaves a suitable substrate. |
Contaminants can survive a quick pass
- Oil and automotive fluids
- Curing compounds, densifiers, and sealers
- Adhesive, paint, or previous coating residue
- Tire dressing, silicone, and detailing products
- Deicing salts and weak surface concrete
- Dust left after preparation
Cracks and joints are different promises
| Condition | Conversation to have |
|---|---|
| Dormant crack | Repair material, preparation, appearance, and compatibility |
| Moving crack | Why movement can transfer through or reopen |
| Control joint | Whether it remains visible, is filled, or is honored |
| Expansion or isolation joint | How movement will continue to be accommodated |
| Spall or broken edge | How unsound concrete is removed and rebuilt |
Moisture is not visible from the surface
A slab can appear dry while transmitting moisture vapor. The applicable test, location, timing, and acceptable limit depend on the coating system and manufacturer instructions. Below-grade basement slabs and garages with drainage or foundation history deserve a candid moisture conversation. If you are evaluating a Fortress project, share that history when discussing basement floor coating options.
For example, the Sikafloor-515 limitations specify a particular moisture measurement and state that an in-slab relative-humidity test is not a substitute for that product’s specified measurement. Ask which test, results and limits govern your proposed system rather than treating every test as interchangeable.
Walk the edges before approving scope
- Garage apron and door termination
- Stem walls, curbs, steps, and vertical faces
- Floor drains and cleanouts
- Expansion material and perimeter joints
- Post bases, equipment pads, cabinets, and fixed objects
- Where chip and topcoat stop
Questions before accepting the proposal
- What mechanical preparation equipment is included?
- How will oil, sealer, adhesive, or old coating be identified and removed?
- What moisture assumptions or testing apply?
- Which cracks and joints may remain visible or reopen?
- How are spalls and weak edges rebuilt?
- What slab-related failures are excluded from the warranty?