Ready Mix Concrete sounds simple — call, order, pour. But there are five mistakes that builders make every single time, and every one of them costs money, time, or structural integrity.

RMC is one of the most engineered products in construction — every ingredient calculated, every batch assessed. Yet most ordering mistakes have nothing to do with concrete itself. They happen before the truck even leaves the plant. Here are the five mistakes that consistently trip up builders, contractors, and first-time homeowners alike — and exactly how to avoid them.

No. 1: Ordering the wrong concrete grade.

This is the most expensive mistake you can make—and the most common. Concrete grades are not interchangeable. M20 is fine for residential slabs; M30 is needed for columns and beams in multi-storey structures; M40 and above is standard for bridges and high-load infrastructure. Ordering a lower grade to save money does not reduce cost — it reduces strength. A structure built on under-spec concrete may look fine on day one and fail under load years later, when repair costs dwarf what was “saved” at the batching stage.

“Always consult your structural engineer or RMC supplier before confirming the grade.”

No. 2: Miscalculating the quantity needed.

Too little and you’re facing a cold joint—a visible, structurally weak seam where fresh concrete meets a partially set pour. Too much and you’re paying for cubic meters that end up hardening in the drum or being dumped on site. Both outcomes are wasteful and avoidable. The formula for calculating concrete volume isn’t complicated, but it’s surprising how often it’s skipped or approximated. Factor in your slab dimensions, column volumes, and beam lengths, and always add a 5-7% buffer for wastage and surface irregularities.

“Ask your RMC supplier to help verify your quantity calculation before placing the order.”

No. 3: Not having the site ready before the truck arrives.

The 90-minute window from batching to placement is non-negotiable—it's chemistry, not a policy. Yet a staggering number of pours are delayed because the site wasn’t prepared: formwork incomplete, reinforcement not in place, pump not set up, access route blocked, or laborers not on site. Every minute spent scrambling after the truck arrives is a minute being subtracted from workable time. A delayed pour doesn’t just waste concrete — it can compromise the integrity of the entire element being cast.

”Run a site-readiness checklist at least 2 hours before the scheduled delivery time.”

No. 4: Ignoring workability and slump requirements.

Workability—how easily concrete can be placed, compacted, and finished—is specified by ‘slump’ in millimeters. A low-slump mix is stiff, ideal for roads and precast elements. A high-slump mix is fluid and needed for congested reinforcement and pump applications. Ordering without specifying slump, or worse, adding water on-site to make the mix more workable, is a critical error. Each liter of water added beyond the designed water-cement ratio directly weakens the final concrete—reducing compressive strength and increasing permeability.

“Specify the required slump value when placing your order, based on pour method and reinforcement density.”

No. 5: Choosing a supplier based on price alone.

Concrete is one of the few construction materials where the cheapest option can bring your building down. An unreliable supplier may cut corners on cement content, use substandard aggregates, or skip quality testing entirely. Without test certificates and proper batch documentation, you have no way of verifying what went into your structure. When something goes wrong—a crack, a failure, a legal dispute—'it was cheaper’ is not a defense.

“Ask for IS code compliance, batch test reports, and delivery documentation as standard with every order.”