Do cob houses really need replastering every year?

No.092 — Read old posts on Tinyfarmlab.com
Reading Time 4 minutes

In many Indian villages, there's a beautiful tradition called Lipayi—
a rhythmic, almost meditative practice of plastering floors and walls with a mix of clay, dung, and water.

It’s an art form passed down through generations.
Organic. Earthy. Aesthetic.

But here’s the thing—
As beautiful as it is, lipayi often dusts, cracks, and requires frequent upkeep.

And so, many assume that all natural plasters are delicate.
That cob houses need to be replastered every year.
That natural homes demand constant maintenance.

But that’s a myth.

We haven’t replastered our cob house in Rishikesh in three years.

And no, we don’t have some magic secret.

People keep asking us for "the recipe."
But when it comes to natural plasters, the truth is,
there is no one-size-fits-all recipe.

What worked in our Rishikesh house didn’t work in Varanasi or Agra.
Because natural materials vary, especially soil.

Here’s what usually goes into a natural plaster:

Binders — Clay-rich soil, Lime
Aggregates — Sand
Fibers — Straw, Cow dung
Additives — Jaggery, Cactus gel, Flour paste, Fermented starch, or even manure

The exact proportions matter—and they change based on what’s available locally.

That’s why every project begins with samples.

We try different ratios.
Apply them on the wall. And wait.

We look for:

• Cracking or shrinkage

• Adhesion to the wall

• Dusting

• Desired color or texture

Only when the sample passes these checks do we go ahead with the final plaster.

Clay Dung Lime Sand Plaster

As we said, there is no fixed recipe—always test batches before applying.
Here’s what has worked for us.

Base Coat

• Mix 1 part clay soil and 2 parts sand, sieved through a 1/8-inch mesh.

Finish Coat

• Use finely sieved clay soil, horse dung, sand, and slaked lime, passed through a 1/16-inch screen.

• Cow dung can be used instead of horse dung if available.

• Suitable for both interior and exterior surfaces.

Mixing & Application

• Mix by hand (with gloves) or use a paint blender for larger batches.

• Use large buckets to prepare big batches.

• The mix should have a pancake batter consistency.

• Apply with:

  • Trowels for flat surfaces.

  • Hands (with gloves) for curved surfaces (to avoid lime burns).

Burnishing for a Smooth Finish

• Burnish just before the plaster fully dries.

• For flat surfaces → Use a stainless steel trowel.

• For curved surfaces → Use a flexible tool like:

  • Folded tarp or plastic.

  • A sponge wrapped in plastic for flexibility.

• Burnish when the plaster doesn’t move under light pressure but isn’t fully dry.

• Once burnished and fully dry, the surface becomes smooth, dust-free, and pleasant to touch.

• Adding lime gives a lighter earthy tone that is easier on the eyes.

Burnishing helps close the pores, making the surface smoother, more water-resistant, and giving it a beautiful texture and color.

Common Recipe for finish coat

• A commonly used ratio:

  • 1 part clay soil

  • 1 part dung

  • 1 part slaked lime

  • 1 part sand

• All ingredients should be sieved through a 1/16-inch screen.

• If sieving dung is difficult, remove long straw fibers before plastering.

For the Tiny Farm Fort, after sampling, we used the following ratios for the final plaster: 2 Clay, 2 Lime, 1 Horse Dung , 1.5 Sand because our clay solid already had some sand content.

We used horse shit because there are no cows in the village.
Cow dung is more water resistant, but horse shit has finer fiber.

Natural plaster, when done right, with care and context,
it’s durable, dust-free, and deeply beautiful.

Natural building isn’t about shortcuts or secrets.
It’s about understanding, experimenting, and listening to the earth.

Love,
Raghav and Ansh

PS: Check out our latest post on LinkedIn where we share our thoughts on CSEB blocks.

What you can watch -

What you can listen to - Clay plastering in Japan Pt1 - Emily Reynolds - BS027

What You Can Read - The Natural Plaster Book

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