Questions to Ask a Concrete Contractor
For homeowners having a driveway, patio, slab or sidewalk poured. Twenty questions on ground preparation, thickness and reinforcement, mix strength, joints and cracking, drainage, curing times, site cleanup, permits, and what the written price actually covers.
The questions
Open any question for the note
What are you going to do to the ground before you pour?
Why ask it
Most concrete that fails early fails from below. You want to hear about removing soft soil, compacting what is left, and how they will handle any tree roots or old fill. A contractor who moves straight to the pour is skipping the part that decides the lifespan.
How thick will the slab be, and what is going underneath it?
Why ask it
Thickness and the compacted base under it are the two numbers to get in writing, because both are invisible once the pour is done. Bids that look cheaper often differ here rather than in the concrete itself.
What mix are you using, and what strength?
Why ask it
Ask for the strength in writing and whether the mix is specified for freeze and thaw if your winters call for it. A contractor who orders the same mix for every job regardless of use has not thought about yours.
Will there be rebar, wire mesh, or fiber in it, and why that one?
Why ask it
The choice matters less than the reasoning and the placement. Ask how reinforcement will be held up off the base, because mesh lying flat on the ground contributes very little to a finished slab.
Where will the joints go, and how soon after the pour do you cut them?
Why ask it
Joints decide where the concrete cracks, which it will. Someone who can sketch the layout and give you a timing window for cutting is planning the cracks. Someone who does not mention joints is leaving them to chance.
All concrete cracks. Which cracks would you come back for, and which would you tell me are normal?
Why ask it
This is the fairest test of a contractor's honesty on the estimate. Straight to a hairline crack being normal and a displaced or widening crack being their problem is a good answer. A promise that it will never crack is not credible.
How are you setting the slope so water runs away from the house?
Why ask it
Drainage is fixed at the moment of finishing and is expensive to correct afterwards. Ask where the water is going to go, and specifically where it will sit after heavy rain, since the standing puddle is the complaint that shows up in year one.
What finish are you giving it, and what is it like when wet?
Why ask it
Finish is a trade-off between grip and appearance, and smooth troweled surfaces get slippery outdoors. Ask to see the same finish they are proposing on a real job rather than agreeing to a word.
What weather would make you postpone this pour?
Why ask it
Heat, cold, and rain in the hours after placing all affect the finished surface. A contractor who names the conditions they will not work in is protecting the job. One who says weather is never a problem is protecting the schedule.
Will anyone add water to the truck once it is here, and who decides that?
Why ask it
Water added on site makes concrete easier to place and weaker once cured. You want to hear that the mix is ordered at the right workability and that any adjustment is a deliberate decision, not something a crew member does with a hose.
How long before I can walk on it, drive on it, or park something heavy?
Why ask it
The three times are different, sometimes by weeks, and driving on a slab too early is one of the most common ways homeowners damage new concrete. Get the dates in writing and plan where vehicles will go in the meantime.
How are you curing it, and are you sealing it? If so, when?
Why ask it
Curing is what happens in the first days and it does more for durability than anything you can do later. Ask what method they use, whether sealing is included or extra, and how long after the pour a sealer should go on.
Who is removing the old concrete, and is disposal in the price?
Why ask it
Demolition and haulaway are a real share of the cost and a common place for a low bid to be quietly incomplete. Ask what happens if there is a second slab underneath the first, which is not unusual.
Where will the truck sit, where will they wash out, and what will my lawn look like afterwards?
Why ask it
Trucks are heavy and washout water is caustic. The answer tells you whether they have thought about your grass, your existing driveway, and your neighbour's, and whether restoring any of it is included.
Are you pulling the permit, and who meets the inspector?
Why ask it
Requirements vary by locality and by what you are pouring. A contractor who knows exactly what your job needs is working in your area regularly. Being told not to bother is a reason to check with the building department yourself.
Is the crew yours, and who will actually be here on the day?
Why ask it
Finishing concrete is a skill that lives in the hands of the person holding the trowel, and that person may not be the one selling you the job. Ask who leads the crew and how long they have worked together.
What is in the written price, and what do you most often end up charging extra for?
Why ask it
Every contractor has a usual change order: unexpected soil, extra base material, a step, a drain. Asking which one comes up most gives you a realistic ceiling instead of a number that only holds if nothing is found.
What does the payment schedule look like, and what is due before you start?
Why ask it
A modest deposit for materials is normal and a large payment before any work is not. Ask what is due at each stage and tie the last payment to the finished surface after any sealing, not to the day the truck leaves.
Can I get your insurance certificate directly from your insurer?
Why ask it
Certificates get emailed as forwarded attachments that may be out of date or belong to someone else. Asking for it from the source is a small, normal request, and reluctance to arrange it tells you plenty.
Can I see a job you poured three or four years ago?
Why ask it
Fresh concrete looks good regardless of what is underneath it. Work that has been through a few winters shows the joints, the surface wear, and the drainage, which is the only version worth judging.
Getting Concrete Poured Well
Practical guidance for the conversation itself
Comparing Bids
Price the Same Specification
Write down the thickness, base depth, mix strength, reinforcement, and finish, then ask each contractor to bid that. Otherwise you are comparing three different slabs, and the cheapest one is usually the thinnest one on the least base.
Ask What They Would Change About Your Plan
A contractor who suggests a different slope, an extra joint, or a thicker section where vehicles turn is thinking about your site. One who accepts every detail without comment may simply be quoting what you asked for.
Get the Numbers on the Estimate, Not in Conversation
Thickness, base, strength, and reinforcement should appear on the written estimate. All four are impossible to verify once the pour is finished, so a verbal assurance is worth very little afterwards.
Ask for the Delivery Ticket
The ready-mix supplier's ticket records the mix delivered and, in most cases, water added on site. Asking for a copy on the day is unremarkable, and it is the only independent record of what actually went in.
On the Day
- Be at home, at least for the first hour and again when they start finishing
- Look at the base before any concrete arrives, since that is your last chance to see it
- Check that reinforcement is held up off the base rather than lying on it
- Note when the trucks arrive and whether anyone runs a hose into the drum
- Ask before they leave when the joints will be cut and when you can walk on it
- Take photographs of the prepared base and the finished surface the same day
Common Pitfalls
Choosing on Price Without Reading the Spec
The savings in a low bid usually come out of base preparation, slab thickness, or reinforcement, all of which are hidden the moment the job is done and expensive to remedy later.
Expecting Concrete Not to Crack
It will, which is why joints exist. The useful conversation before signing is about which cracking is normal and which is a defect the contractor will return for, agreed in writing rather than argued about in spring.
Letting a Pour Go Ahead in Poor Conditions
Saturated or frozen ground, extreme heat, and rain shortly after placing all show up in the finished surface. Postponing a week is cheaper than living with a scaled or dusting slab, and a good contractor will suggest it first.
Paying in Full on the Day
Hold a final payment until the joints are cut, any sealing is done, and you have seen the surface after a heavy rain. That last visit is much easier to arrange while a balance is outstanding.