Lime Wall Plaster - Color Skim 121 Chalk

Color Skim is a smooth, non-sanded lime and fine marble plaster that replaces paint on interior walls. It goes on as a paper-thin skim coat with a Venetian plaster trowel and gives soft, natural color with visible movement from the trowel and a breathable mineral finish (sealing reduces breathability; see Sealing and sheen). It can be applied over primed drywall, primed concrete board, and existing plaster walls.

• Coverage: about 50–75 sq ft per gallon kit for the standard two coats. A third coat uses about 1.5 times the plaster.
• Sizes: Gallon Kit, Quart Kit, and a 2″ color chip for sampling.
• Primer: Lime Plaster Primer – Smooth on drywall and other non-mineral surfaces (about 300 sq ft per gallon).
• Sealer (optional): Lime Plaster Sealer in Gloss or Low Gloss (about 300 sq ft per gallon for the typical two coats). Both add sheen; Gloss gives more sheen than Low Gloss.
• Surfaces: interior walls only. Color Skim is not for exterior use.

Each kit has two parts: Part A, the dry plaster mix, and Part B, the liquid with colorant. The color is built into Part B, so the plaster is integrally colored. Pour Part A into Part B and mix to a smooth, lump-free paste with a drill mixer attachment designed for paint or plaster.

Color Skim has a slow set compared with gypsum skim-coat products, which gives you more working time. Under normal conditions it does not need misting or damp curing. Once mixed, the plaster stays workable for about 2 hours in normal conditions (around 70°F).

1. Prepare: bring the drywall to a smooth surface (Level 4 finish or higher is ideal), with all taping, mudding and hole-filling done.
2. Prime: roll on one even coat of Lime Plaster Primer – Smooth and let it dry fully.
3. First coat: trowel on at 1/16″ or thinner. Don't try for full coverage or build thickness; heavy coats can crack. Several thin layers beat one thick one.
4. Smooth: once dry, lightly sand with fine sandpaper or knock down high points with a plaster knife.
5. Second coat: apply the second coat. In warm conditions you may mist the surface just before applying to extend working time. Don't mist finished work unless you plan to re-trowel it.
6. Optional third coat and burnishing: add a third coat if needed. Once the final coat is fully dry, burnish with the trowel to raise sheen and depth, or leave it unburnished for a matte look (easier for DIY).

Keep air and surface temperatures between 55°F and 85°F (13–29°C). Ideal relative humidity is 50–75%. Color Skim is a final color finish; don't use it to build up surfaces or fill gaps.

Seal about two weeks after the final coat. The usual range is 7 days to 3 weeks, closer to 3 weeks when drying conditions are poor. Use water-based sealers only. Apply Lime Plaster Sealer with a microfiber roller, or a paintbrush for small projects. Two coats is typical (one gallon covers about 300 sq ft for both coats). Gloss and Low Gloss both add sheen, and Gloss gives more sheen than Low Gloss. Sealing also reduces the plaster's breathability. On low-touch walls you can skip sealer to keep a matte, unsealed finish.

For wax, soap or oil finishes, wait at least 48 hours (1 week recommended).

Step-by-step help: How to apply lime plaster over drywall and Gloss vs Low Gloss vs no sealer.