Uniform support matters beneath concrete
The ground beneath a slab is part of the project, even though you will not see it afterward. NRMCA’s cracking guidance explains the need for uniform, adequately compacted support. Soft spots and unsuitable material need attention before placement.
“Uniform” means the support is considered across the slab, rather than only where the ground looks convenient to work. A new patio, a driveway extension and a building slab may present different site and use questions.
Ask the contractor to explain what they found and how the proposed preparation addresses it. This guide does not identify your soil or set a compaction target. It also cannot promise that preparation will prevent all concrete cracking.
Existing slab removal reveals more information
With replacement work, the old concrete hides part of the site. The initial proposal should explain what is assumed about that covered ground and what happens if removal reveals something different.
Consider a driveway quote that includes taking out the existing slab. Ask whether the provider will pause to discuss additional excavation or fill before doing work beyond the agreed scope. A useful change record identifies the area, proposed treatment and price adjustment.
The International Masonry Institute emphasizes assessing deterioration and its cause before selecting a remedy. Simply exposing the ground does not, by itself, diagnose every issue. Keep the removal boundaries and preparation decision connected.
Ask what the preparation specification includes
You do not need to design the base yourself. You do need enough explanation to understand what is being bought.
| Preparation question | Useful detail in the proposal |
|---|---|
| What is removed? | Existing material and the agreed excavation limits |
| What is retained? | Material the provider considers suitable to remain |
| What is added? | Specified fill or base material and where it is used |
| How is it prepared? | Compaction approach and any required checks |
| What is the final use? | Walking, vehicles, a structure or equipment |
NRMCA’s finishing guide connects support, levels and drainage with the planned flatwork. A thicker slab or more steel should not be used as a vague substitute for explaining the ground beneath it. Read the thickness and reinforcement guide for those separate decisions.
Record the preparation allowance
Ask whether preparation is included in the main price, covered by an allowance or subject to a separately agreed change. The answer should identify the assumptions behind the figure.
Tex-Tex Concrete’s DFW pricing lists preparation as a scope variable. Its published bands do not mean every job has the same preparation charge, and they are not this website’s prices. Compare the actual work using the quote worksheet.
For your first enquiry, “replace the driveway” or “add a backyard pad” is enough. Get a Concrete Quote with your location and callback number; the provider can discuss ground preparation during assessment.