Research-based planning guide
Hollow-sounding garage concrete: assess the slab before coating
If parts of a garage slab sound hollow or seem to be separating, ask for a substrate assessment before selecting a coating. The issue may involve the concrete, an existing topping or an old coating. A decorative finish shouldn't be used to hide an unexplained condition.
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Describe the observation without diagnosing it
Mark where you noticed the sound and record visible cracks, loose material or changes in level. Share previous repair and resurfacing information if available. Don't strike the floor aggressively or begin removing material to see what is underneath.
Photographs help show location and surface condition. They cannot establish the depth or extent of a concealed defect.
Ask what layer is affected
| Possible finding | Question for the assessor |
|---|---|
| Existing coating separation | What removal and adhesion evaluation are proposed? |
| Topping or patch separation | Is the repair still sound and compatible? |
| Weak or delaminated concrete | How will the extent and appropriate repair be established? |
| Movement or structural concern | Is another qualified professional needed? |
These are assessment categories, not a homeowner diagnosis. Sika's substrate-preparation guidance describes evaluation and preparation as part of selecting a suitable flooring system.
Compare the repair assumptions
Ask whether the estimate assumes sound concrete or includes investigation and removal of unsound areas. If the extent remains uncertain until preparation, request an allowance or pricing method and an approval point for extra work.
Clarify what the repair is intended to accomplish. A surface patch, a leveling material and structural work have different purposes. The coating contractor should explain when the scope goes beyond their work.
Keep evidence before covering it
Request photographs of exposed conditions and completed repairs where appropriate. Keep product details and any assessment report. Ask how the repaired surface is checked against the proposed coating's requirements before the decorative layers are installed.
If the recommendation is to pause the floor project for further evaluation, use that information. Choosing a color sooner won't resolve a substrate question.
Read the damaged-concrete coating guide and crack-repair information. To request an assessment, include the location of the affected areas and your repair history.