Most concrete problems trace back to a conversation that never happened before the pour. A missed question about mix strength, delivery timing, or weather conditions can turn into a cracked driveway or a failed foundation inspection months later.
At Wilches Ready Mix, we'd rather answer detailed questions upfront than deal with a problem after the concrete has cured. This guide covers the questions worth asking any concrete supplier before you order, along with the contractor mistakes we see most often across the GTA.
Concrete is one of the few building materials where mistakes aren't visible until it's too late to fix cheaply. Once a batch is poured and set, correcting a wrong mix strength, poor slump control, or an unplanned freeze means removal and repouring, not a simple patch.
Asking the right questions before ordering shifts the burden of catching problems from after the pour to before it, which is the only point where a mistake actually costs little to fix.
Every mix should have a clear compressive strength rating attached to it. If a supplier can't tell you the MPa rating of what's in the truck, there's no way to confirm it matches what your project actually needs.
Concrete has a limited usable window after batching, often just a couple of hours. Ask for a specific delivery window, not a vague estimate, and ask how the supplier communicates if a delay happens.
Freeze-thaw exposure, vehicle loads, and soil conditions all affect which mix is appropriate. A supplier familiar with GTA conditions should be able to explain why a specific mix suits your project, not just quote a price.
Slump affects workability and, indirectly, strength. Confirm what slump range to expect, and ask what happens if a delivered load doesn't meet that specification on arrival.
If your pour falls outside peak summer season, ask directly whether a Cold-Crete or similar formula is available, since not every supplier stocks specialty mixes as standard.
Ordering by Price Alone: Choosing the lowest quote without confirming mix specification is one of the most common and costly mistakes. A cheaper mix that doesn't match the required MPa rating can lead to cracking or failed inspections that cost far more than the initial savings.
Not Planning for Weather: Scheduling a pour without checking the forecast for the days following, not just pour day itself, is a frequent oversight. A late-season pour without a cold-weather mix can suffer freeze damage before reaching sufficient strength.
Rushing Site Prep to Meet Delivery: Concrete's limited working window creates pressure to have the site ready the moment the truck arrives. Rushing formwork or reinforcement placement to meet that window is a common source of structural issues that show up long after the pour.
Skipping the Slump Check: Some crews accept a delivery without confirming slump on site, assuming the batch matches the order. A quick check on arrival catches problems before the concrete goes into the ground, when correcting them is still simple.
Assuming All Suppliers Are Interchangeable: Treating concrete as a commodity where any supplier will do overlooks real differences in mix consistency, delivery reliability, and local experience, all of which affect the outcome of the pour.
| Question | Why It Matters |
|---|---|
| What MPa rating am I getting? | Confirms strength matches your project's requirements |
| What's the delivery window? | Protects against concrete exceeding its usable time |
| Does this mix suit my site conditions? | Matches mix to soil, load, and weather exposure |
| What slump will the load arrive at? | Confirms workability and water-to-cement ratio |
| Do you offer cold-weather mixes? | Prevents freeze damage on late-season pours |
| Temperature | Initial Set | Full Cure | Notes |
|---|---|---|---|
| Above 20°C | 4–6 hours | 28 days | Summer ideal |
| 10–20°C | 6–10 hours | 28–35 days | Spring and fall |
| 5–10°C | 10–16 hours | 35–45 days | Cold-Crete recommended |
| Below 5°C | 16+ hours | 45+ days | Cold-Crete required |
A contractor requiring Ready Mix Concrete in Mississauga had previously ordered concrete without confirming the MPa rating in writing, and received a lower-strength mix than the project required after a supplier substitution. On a later project, the same contractor asked us to confirm MPa rating and slump specification before delivery, which caught a mismatch in the initial order before the truck even left the plant.
Gursharan Marwaha: "Very good, very friendly, very affordable compared to others, quick response, same day delivery!"
radiomen123: "This is the second time in a few years that I use their service. Each time they were on time and the drivers were very responsible and zero issue. I will highly recommend their services."
Stephen O'Keeffe: "I ordered concrete on a Saturday evening. They answered the phone when no one else did. Brought me the concrete on time, fair pricing and the driver was very patient."
Confirming the MPa rating in writing matters most, since it's the clearest way to verify the mix matches what your project actually requires.
Choosing a supplier based on price alone, without confirming mix specification, delivery reliability, or the supplier's experience with similar projects.
Yes, especially for larger pours where crew scheduling depends on a confirmed arrival window rather than a rough estimate.
Asking the right questions upfront is the cheapest insurance policy on any concrete project. Wilches Ready Mix has answered these questions for GTA homeowners and contractors for over 20 years, backed by more than 1,500 completed projects.
Call us at 647-891-4740 and ask us anything before you order. We'd rather answer questions now than fix problems later.