Grind the slab flat, clean and dry to within about 3 mm over 2 m. Remove trowel ridges, old adhesive and laitance, then stop — LVP sits over the prep surface and every defect telegraphs through.
For luxury vinyl plank (LVP), grind the slab flat, clean and dry. Most manufacturers require flatness within 3 mm over 2 meters; high spots, trowel ridges and old adhesive telegraph through the thin planks and cause hollow spots or wear.
Start by scraping any old adhesive, paint or curing compound. If residue is thin, a single coarse grinding pass opens the surface; if it is thick (black mastic, epoxy), use PCD tooling first. The goal is a uniform, matte concrete surface, not a polished floor.
| Defect | Fix |
|---|---|
| Trowel ridges / trowel marks | Grind with 30/46 metal bond |
| Old carpet glue / mastic | PCD scrape, then 30 grit clean-up |
| Release agent / curing compound | Grind until sand aggregate shows uniformly |
| Low spots | Do not grind; patch with self-leveler after grinding |
A coarse trapezoid grinding disc in 30/46 grit removes ridges quickly while keeping the slab flat. For adhesive build-up, a PCD trapezoid tool strips it in one or two passes before the metal-bond cleanup. Do not polish — you want a slightly rough, profiled surface for the underlayment adhesive.
A: Only when the slab is already smooth and you are refining. On rough or ground-new concrete, skipping leaves a scratch pattern finer pads cannot resolve.
A: If segments glaze and stop cutting, the bond is too hard; if they wear flat in under half a set, it is too soft. Match bond to concrete hardness.
A: Dry grinding with a HEPA vacuum is standard on polished concrete jobs; wet grinding is mostly used for stone and edge work to control dust and heat.
A: Change the whole set together once segment height drops by half or the cut rate slows. Mixing new and worn plates causes uneven scratch patterns.
Choosing the right bond, grit and technique for your concrete job saves tooling cost and avoids rework. Match the tool to the slab, work in the correct grit sequence, and keep plates balanced — the floor will tell you when you are ready for the next step. Contact JOY TECH for tooling recommendations matched to your machine and concrete hardness.
