Cabro vs a concrete slab

Both are concrete. The difference is that cabro is thousands of small pieces locked together in sand, and a slab is one big piece. That single fact explains almost every advantage and every trade-off.

Where cabro wins

Lifts and relays without demolition: Need to reach a buried water pipe or cable? Lift the blocks, do the work, relay them. A concrete slab means a jackhammer and a patch that never matches.
Moves with the ground instead of cracking: Small movements in the soil open a joint slightly; they crack a slab. That matters on Kenyan black cotton soil.
Usable the day it is laid: No 7-day curing. The compactor runs, the sand goes in, and you can drive on it that evening.
Individual blocks can be replaced: Oil stain, chipped block, a settled patch — swap the affected blocks and it looks new again.
Better grip when wet: The joints and textured faces give tyres and feet something to hold on wet days, unlike a smooth trowelled slab.

Where a slab wins

A perfectly smooth surface. For a workshop floor where you slide heavy items, or a basketball court, a trowelled slab is better.
Very small areas. A 4 m² landing is quicker to cast than to pave with kerbs.
Weeds. A slab has no joints for weeds to take hold in. Cabro joints need sand topped up and the odd weed pulled.

Cost on day one

For the same duty, supply-and-lay cabro and a reinforced slab usually come out close. The slab needs steel mesh, formwork and seven days of curing before you can use it; cabro needs kerbs and a compactor and is in use the same evening. Over ten years cabro is usually cheaper, because repairs are lift-and-relay rather than break-and-recast.

The trade-off to state openly

Cabro only performs as well as its base. Expensive blocks on a cheap, uncompacted base will sink and rut within a year.
Joint sand needs topping up every few years, and weeds can take hold in joints that are left empty.
A complex pattern costs more to lay and wastes more blocks in cuts than a simple one.

On a properly prepared base, cabro lasts 15–25 years or more. We do not promise beyond that.

On black cotton soil

This is where the choice is clearest. Black cotton soil swells in the rains and shrinks in the dry season. A slab on it cracks along the movement lines, however much steel is in it. Cabro on a properly built base — black soil out, murram in, hardcore compacted — flexes at the joints and stays whole. Either way the base work is the same and must be done; cabro just forgives the ground better afterwards.

If you are still deciding, book a free site visit — the ground usually settles the argument.

Questions on this

Which lasts longer, cabro or a concrete slab?

On a properly prepared base both last 15–25 years or more. The difference is what happens when something goes wrong: a cracked slab is a demolition job, a damaged cabro area is a lift-and-relay job.

Can I lay cabro over an existing concrete slab?

Yes, if the slab is sound and there is enough height at the doors and gate. You need a sand bed and edge restraint on top of the slab, and you must keep the falls for drainage.

Which is better for a slope?

Cabro in herringbone with a concrete haunch at the low edge. A slab on a slope needs expansion joints and still tends to crack across the fall line.