Why do concrete blocks vary so much in price?

Cement content, almost entirely. A block is sand, aggregate and cement, and the cement is the expensive part, so a cheap block is cheap because it is lean. You can feel the difference: knock two together and a lean block crumbles at the corner where a properly made one rings.

What should I check on a fencing post?

The reinforcement and its cover. A post is a slender element resisting bending from strained wire, so the steel inside it is what keeps it standing. Cheap posts save money by reducing or omitting the steel, or by placing it with too little cover, in which case it rusts and splits the post from the inside.

How do I know it was cured properly?

You largely cannot by looking, which is why it matters who made it. Concrete gains strength by hydrating, and hydration needs water present for weeks. A unit demoulded early and stacked in the sun stops gaining strength and looks perfectly finished. Ask the yard how long units are cured before dispatch.

Is precast cheaper than casting on site?

For anything repetitive, usually yes once you account for formwork, labour and waste, and it is more consistent. For one-off shapes, casting in place is often the better answer. We will tell you which applies to your job.

Precast Concrete Prices in Kenya: Posts, Panels, Blocks and Culverts

What precast costs in Kenya

Rates below are supplied ex-yard, reviewed August 2026. Installation is quoted separately, and delivery depends on distance and quantity.

Where the price difference comes from

Precast prices in Kenya vary far more than the material should allow, and there are only really three explanations.

Cement content. The main one. Concrete strength is bought with cement, and cement is the expensive constituent. A block or post priced well under the market was made lean, and lean concrete is weaker in exactly the way you cannot see.

Reinforcement. For posts and panels, the steel inside decides whether the unit survives its working life. Reducing the bar size, reducing the number of bars, or placing them with too little cover all save money immediately and all fail later. Insufficient cover is the worst of the three, because the steel corrodes, expands and splits the concrete from within.

Curing. The invisible one. Concrete hydrates rather than dries, and it needs water present for weeks, most of the strength arriving in the first seven to twenty-eight days. A unit demoulded early and stacked in the Nairobi sun simply stops gaining strength. It looks identical to a properly cured unit and can be substantially weaker.

What this means practically

You cannot inspect your way to quality on precast. The surface finish tells you about the mould, not about the mix, the steel or the curing.

What you can do is ask three questions: what the cement content is, what reinforcement is in it, and how long units are cured before dispatch. A yard that answers all three readily is telling you something. One that treats the questions as unreasonable is telling you something too.

Sizing culverts

The commonest and most expensive precast error we see is buying the diameter that fits the budget rather than the one that fits the catchment. An undersized culvert does not fail gradually. It backs up in the first serious storm of the long rains and takes the road or the driveway with it, and the replacement costs many times the saving.

Size it for the water, not for the price list.

Rates

Work	Rate	Notes
Concrete fencing post	KES 450 - 1,200 each	By height and reinforcement. A 7ft post is the common size
Precast wall panel	KES 900 - 2,200 each	By panel size and finish
Concrete block, 6 inch	KES 55 - 90 each	By cement content. The cheap block is cheap on cement
Concrete block, 9 inch	KES 80 - 130 each
Culvert ring, 450mm	KES 4,500 - 7,000 each	By diameter and wall thickness
Culvert ring, 600mm	KES 7,500 - 12,000 each

Rates reviewed August 2026. Every job is confirmed with a written quotation before work starts.