How fast can you build with cob?

No.119 — Read old posts on Tinyfarmlab.com
Reading Time 5 minutes

The first cob building we ever made took us three years.
Our next one should take one year.
Today, we're trying to build three cottages in three months.

Not because cob has changed.
Because we have.

Gone are the days when architects could disappear for years and emerge with a finished masterpiece.

Today, we're competing with fast-setting cement,
lightweight steel,
prefab panels,
and modular construction.

No matter how sustainability-oriented you are...
Everyone wants their dream project yesterday.

So let's answer the question we get asked more than any other.

How fast can you really build with cob?

The answer nobody likes...

It depends.
Not because I'm trying to avoid the question.
Because "building with cob" isn't one activity.

It's dozens of different activities happening together.

Digging foundations.
Mixing cob.
Building walls.
Moving scaffolding.
Installing windows.
Designing roofs.
Sourcing timber.
Waiting for the weather.

Every project is a balance between these.

Our biggest lesson

When we built Tiny Farm Fort, we assumed placing cob on the wall would be the slow part.

It wasn't.
Mixing enough cob was.
If you don't have enough people mixing, the builders simply stand around waiting.

Below about four feet of wall height,
the wall rises surprisingly quickly.

The challenge is producing enough material to keep feeding it.

Above four feet, everything changes.
now you're lifting heavy cob higher.

You're constantly moving scaffolding.

This is where it makes sense to make cob balls and pass it around.

Openings for doors and windows demand precision instead of speed.
Progress naturally slows.

The walls are only half the story

When people ask,

"How long does a cob house take?"

they're usually imagining only the walls.

But walls are only one chapter.
The real time is spent in the details.
Sculpting niches.
Carving curves.
Installing deadmen to anchor the roof.
Applying multiple coats of plaster.
Allowing finishes to dry.

We always say that building the walls in 10% of the work,
90% of the work is finishing it and making it livable.

What about Adobe?

People often assume that Adobe is automatically faster.

Sometimes it is. Sometimes it isn't.

If you're buying ready-made earth blocks,
then yes, you can lay them much like masonry.

But if you're making your own adobe,
there's a surprising amount of hidden work.

First, every brick needs to be moulded.
Then it has to be removed from the mould without breaking.

Then laid out to dry. Turned.
Protected from unexpected rain.
Stacked.
Stored.
Transported to the wall.

Only then can construction begin.

Cob skips almost all of those steps.
You mix it...
...and build immediately.

Adobe also comes with trade-offs.

Flat bricks naturally encourage straight walls and right angles,
while cob happily becomes curves, benches, shelves, and sculptural forms.

Adobe relies on hundreds
or thousands of individual units, introducing more joints into the wall.
Cob creates a continuous monolithic mass.

Neither system is universally better.

They simply optimise for different things.

So how fast is cob?

For a modest one-storey tiny cottage upto 200-300 sq ft with good planning, favourable weather, and a small dedicated team, it's entirely realistic to build from foundation to a roof-ready structure in about five weeks.

The walls themselves are rarely the limiting factor.

Planning is.
Material sourcing is.
Roof construction is.
Finishing is.

Speed comes from organisation

That's exactly what we're experiencing on our current project in Bandhavgarh.
Our clients come from a real estate background.
They understand that delays often cost more than investing in the right people upfront.

Instead of treating cob as an experimental craft,
they've approached it like any professional construction project.
They have mobilised a team of more than 25 people employed on a 3-acre site.

A labour manager coordinates the workflow.
Based on our advice, they have hired a site engineer who keeps the work progressing and makes sure that drawings are being followed.

Stone masons build the foundations.
Metal fabricators prepare door and window frames.
Local labour has been trained over multiple site visits.

Most importantly, the work is staggered.

One cottage is being excavated.
Another is having cob walls lifted.
A third is preparing for its roof.

Nobody is waiting for the previous building to finish before starting the next.

That's how projects become efficient.

Can cob be built even faster?

Absolutely.

Around the world, builders are experimenting with rammed cob, cob placed inside reusable formwork, and mechanical mixers capable of producing consistent batches far faster than foot-mixing.

Some teams even erect the roof structure first, using timber or steel columns, allowing cob work to continue under shelter through changing weather.

Innovation isn't replacing cob.
It's improving the way we work with it.

The biggest factor nobody talks about

The calendar.

In northern India, the fastest projects don't begin with digging.
They begin with timing.

Design during the summer or monsoon.
Complete foundations as the rains come to an end.
Raise the cob walls through the cool, dry winter.
Aim to have the roof on before the following monsoon arrives.

Good builders don't just understand materials.
They understand seasons.

So... how fast can you build with cob really?

Fast enough that the material is no longer the biggest constraint.
The limiting factor is almost always planning, logistics, and people.

The first cob house taught us how to build.
The second taught us how to organise.
This third project is proving us how to scale.

Perhaps that's the real lesson.

Cob isn't slow.
Beginners are.

And like every craft,
speed comes with experience.

What questions do you have about building with cob?

Reply to this email and let me know.

There's a good chance your question will become the next edition of Tiny Farm Friends.


P.S.: If you are on LinkedIn, let’s connect!


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