Precast Concrete in Nairobi: Posts, Panels, Blocks and Culverts
from KES 55 each
Why precast beats casting on site
Precast is made in a controlled environment: the mix is batched rather than gauged, the units are vibrated in the mould, and they are cured before they are moved. Casting the same items on site in the open means a mix judged by eye, compaction by whatever is to hand, and curing at the mercy of the weather.
For anything repetitive, posts, panels, blocks, kerbs, culvert rings, that difference shows up directly in strength and in how long the item lasts outdoors.
What curing actually does
Concrete does not dry. It hydrates, and hydration needs water present for weeks, with most of the strength gained in the first seven to twenty-eight days.
A unit demoulded early and stacked in the Nairobi sun stops hydrating and stops gaining strength. It will look finished and be substantially weaker than it should be, and no inspection of the surface will tell you. This is the single largest quality difference between one precast yard and another.
What to ask before you buy
Fencing posts: the reinforcement. A post is a slender element carrying bending load from a strained wire, and how much steel is in it, and whether the steel has cover, decides whether it survives. A cheap post is cheap because the steel was reduced or omitted.
Blocks: the cement content. A block that crumbles at the corner when you knock two together was made lean. Blocks vary more in Kenya than almost any other building product, and the price tracks the cement rather closely.
Culvert rings: the wall thickness and the diameter together. An undersized culvert is not a saving, it is a road that washes out in the long rains.
Delivery and handling
Precast is heavy and brittle in exactly one direction. Posts and panels crack from being dropped and from being lifted at the wrong point, not from being used. We deliver on the flat and we say where to lift. Damage after that is honestly harder to argue about, which is why we would rather explain it at the point of delivery.
See what ready-mix costs, or the areas we cover.