Fixing Patchy 'Tortoiseshell' Limewash Effect
Learn what causes uneven or patchy limewash finishes—and how to correct them for a smooth, natural result.
Q. Why is my limewash finish in individual patches instead of blended clouds?
Tortoise-shelling is a term that describes a limewashed wall finish that appears as tight, individual patches sitting next to each other on a wall, rather than an organic, seamlessly blended texture. This effect is due to limewash clouds not being stretched and feathered out far enough and when clouds are not blended into one another sufficiently, while the paint is still wet.
Tortoise-shelling may also occur if your surface is not absorbent, due to incorrect wall preparation. Limewash requires an absorbent surface to adhere to the wall, for the purpose of durability, but also to ensure ease of limewash application and to achieve a desirable textural finish. An absorbent surface allows the paint to blend and spread seamlessly, absorbing into the wall while blending.
See our Surface Guides to ensure you have prepared your wall correctly, and YouTube video for information on checking wether your wall is absorbent.
Q. How do I fix my 'tortoiseshell' patchy limewash finish?
To remedy a tortoise-shelled wall, simple apply a thin, third coat of limewash, ensuring that the paint is feathered and stretched as far as it will naturally go. Don’t be afraid to use your whole arm and really stretch and feather the paint out, avoiding small, tight patches. Ensure that the pattern of cloud placement is not repeated in the same place as the last coat, keep placement of clouds organic and avoid a grid pattern.
Still not working?
If a third coat doesn’t resolve the issue—or begins to look over-applied (which can happen by the fourth coat)—consider starting fresh:
- Apply 1 coat of Bauwerk Prep Coat
- Follow with 2 coats of limewash paint, using improved blending technique.
Refer to our helpful Youtube videos with instructions and tips on how to correctly apply our limewash– a great visual way to help understand our popular cloud technique.
Tips to Prevent a Patchy Limewash Finish
- Blend clouds into each other as you go Don’t paint each cloud right up to the edge of the last—feather and overlap them for a seamless transition.
- Avoid spaced-out or randomly placed clouds Painting too far apart (or by two painters without blending as you go) can cause uneven patches.
- Keep a wet edge at all times Blend each cloud into the next while the edges are still wet to prevent harsh lines or dark patches. Avoid working in straight lines—move organically to keep all edges wet as you go.
- Vary your cloud placement Avoid placing clouds in the same positions with each coat—keep it organic, not a grid.
- Stretch and feather the paint Use your whole arm to apply thin, sweeping movements. Don’t leave small, isolated patches.
- Watch out for over-absorbent walls While not always the issue, highly absorbent surfaces can exaggerate patchiness. Follow the recommended preparation steps for your wall type to help regulate absorption and ensure a more even finish.
