Lime plaster walls have a depth and softness that paint can't match: color that seems to move as the light changes, and a mineral surface that looks and feels handmade. The good news is that you don't need traditional three-coat plastering to get that look on modern drywall. With a thin decorative skim coat like Color Skim, you can transform a primed drywall wall in two coats.
This guide covers everything from wall prep to sealing, using the Color Skim system. Read it all the way through before you start, then practice on a sample board or a small wall before your main room.
What you'll need
Materials
- Color Skim kit(s) in your chosen color: Gallon Kit ($96) or Quart Kit ($32). Each kit has two parts: Part A (dry plaster mix) and Part B (liquid with colorant).
- Lime Plaster Primer – Smooth: about 300 sq ft per gallon.
- Optional: Lime Plaster Sealer in Gloss or Low Gloss: about 300 sq ft per gallon for the typical two coats.
Tools
- Venetian plaster trowel
- Drill mixer attachment and a drill
- Mixing bucket, paint roller and tray (for primer)
- Fine sandpaper or a plaster knife (for knocking down high spots between coats)
- Spray bottle (optional, for warm conditions), drop cloths and painter's tape
Browse more in Plaster Tools.
Step 1: Work out how much you need
Measure the wall area (width × height for each wall, minus large openings). Color Skim covers about 50–75 sq ft per gallon kit for the standard two coats. The range depends on your wall and how tightly you trowel. A third coat uses about 1.5 times the plaster. The project calculator on each Color Skim product page will do the math for you.
Not sure about the color yet? Order 2″ color chips for $5 each and look at them on your wall in morning and evening light before you buy kits.
Interior only: Color Skim is made for interior walls. Don't use it outdoors.
Step 2: Check your conditions
Plan your work for when air and surface temperatures are between 55°F and 85°F (13–29°C). Ideal relative humidity is 50–75%. Very warm, dry rooms shorten your working time. Cold, damp rooms slow drying and curing.
Step 3: Prepare the drywall
Color Skim is a thin decorative color finish, not a leveling coat. It will show what is underneath, so prep matters.
- Bring the drywall to a smooth surface. A Level 4 finish or higher is ideal.
- Finish all taping and mudding and fill any holes before you start.
- Make sure the wall is clean, dry and stable.
- Mask trim, outlets and adjoining surfaces with painter's tape.
Don't use Color Skim to fill gaps or build up surfaces. Fix those in the drywall first.
Step 4: Prime
Roll on one even coat of Lime Plaster Primer – Smooth with a paint roller and let it dry fully. The primer prepares drywall and other non-mineral surfaces to accept the plaster. At about 300 sq ft per gallon, one gallon of primer covers far more wall than one gallon kit of plaster, so most rooms need just one.
Plastering over existing mineral plaster instead? Color Skim can also go onto a dampened mineral plaster substrate as a final color finish.
Step 5: Mix the two-part kit
Each Color Skim kit has two parts:
- Part A: the dry plaster mix
- Part B: the liquid, which carries the colorant
Pour Part A into Part B, then mix with a drill mixer attachment designed for paint or plaster until you have a smooth, lump-free, workable paste. Because the color is in Part B, the plaster is integrally colored all the way through.
Working time: once mixed, Color Skim stays workable for about 2 hours in normal conditions (around 70°F). Mix an amount you can apply in that window. Warmer, drier rooms shorten it.
Step 6: Apply the first coat
Load a small amount of plaster on your Venetian trowel and apply it in short, overlapping strokes, holding the trowel at a low angle.
- Keep it thin: 1/16″ or thinner.
- Don't chase full coverage. It's fine if the primer shows through in places on the first coat. This is a decorative color finish, and it can crack if applied too thickly.
- Several thin layers are always better than one thick one.
Color Skim has a slow set compared with gypsum skim-coat products, so you have time to work without rushing. That makes it friendly for people new to plaster. Under normal conditions it doesn't need misting or damp curing as it dries.
Step 7: Smooth between coats
Once the first coat is dry, lightly sand with fine sandpaper or knock down high points with a plaster knife so the second coat goes on smoothly. Wipe or brush off dust.
Step 8: Apply the second coat
Apply the second coat the same way: thin, overlapping strokes. This coat brings the color together and creates the soft movement lime plaster is known for. Vary your stroke direction for more movement, or keep strokes consistent for a calmer look.
Warm conditions tip: if the room is warm, you may mist the surface lightly just before applying the second coat to extend your working time. Don't mist finished work unless you plan to re-trowel that area.
Two coats is the standard Color Skim finish.
Step 9 (optional): Third coat and burnishing
If you want more depth or a few areas need it, apply a third coat once the second is dry (it uses about 1.5 times the plaster). Then choose your finish:
- Matte: leave the final coat unburnished. This is the easiest route for DIY and gives a soft, velvety look.
- Burnished: once the final coat is fully dry, burnish the surface with your trowel to increase sheen and depth.
Before initial set, you can also re-wet the surface and work it to a smoother, more refined finish.
Step 10: Cure and seal (optional)
Let the plaster cure before sealing. Plan to seal about two weeks after the final coat. The usual range is 7 days to 3 weeks, closer to 3 weeks if drying conditions are poor (cool or humid). Use water-based sealers only.
- Lime Plaster Sealer comes in Gloss and Low Gloss. Both add sheen; Gloss gives more sheen than Low Gloss.
- Apply with a microfiber roller, or a paintbrush for small projects. Two coats is typical.
- Unsealed Color Skim is breathable. Sealing reduces breathability.
- On low-touch walls (above head height, formal rooms, ceilings) you can skip sealer to keep a fully matte look.
- For wax, soap or oil finishes, wait at least 48 hours (1 week recommended).
Not sure which to choose? See Gloss vs Low Gloss vs No Sealer.
Troubleshooting
I see cracks
Cracks usually mean the coat went on too thick. Keep each coat at 1/16″ or thinner, and build depth with additional thin coats rather than heavier ones.
The plaster is drying too fast
Check your temperature and humidity (55–85°F, 50–75% RH). In warm rooms, mist lightly right before the second coat, and work in smaller sections.
The surface feels rough after the first coat
That's normal. Lightly sand or knock down high points before the second coat.
The color looks patchy
The first coat often does. The second coat evens out coverage, and some tonal movement is part of the character of a hand-troweled lime finish.
Quick checklist
- Measure: about 50–75 sq ft per gallon kit for two coats.
- Sample with $5 color chips.
- Smooth drywall (Level 4+), taped, mudded and filled.
- One coat of Lime Plaster Primer – Smooth, fully dry.
- Pour Part A into Part B; mix with a drill mixer attachment. Use within about 2 hours (~70°F).
- First coat, 1/16″ or thinner; let dry.
- Lightly sand or knock down high points.
- Second coat (mist first only if warm).
- Optional third coat; burnish or leave matte.
- Seal about 2 weeks later (7 days to 3 weeks, closer to 3 in poor drying) with two coats of Gloss or Low Gloss (microfiber roller), or skip it on low-touch walls.
Ready to choose your shade? Browse all 34 Color Skim colors →
More Color Skim guides
- Lime plaster vs Venetian plaster vs Roman clay vs limewash
- How to choose a lime plaster color
- Gloss vs Low Gloss vs no sealer
- Shop all 34 Color Skim colors