Most commercial concrete contractors do guarantee their work, usually through a written warranty in the contract that covers defects in workmanship and materials for a set period, often one year from substantial completion. What a warranty does not usually cover matters just as much: normal shrinkage cracking, damage from loads or chemicals the concrete was not designed for, and problems caused by other trades or by the soil. The only warranty that counts is the one written into your contract, so read it before award, not after a problem shows up.
What a concrete warranty usually covers
- Workmanship defects. Scaling, spalling or surface failure caused by how the concrete was placed, finished or cured.
- Failure to meet the specification. For example, a floor that did not meet its flatness numbers when tested, or concrete that did not reach the specified strength.
- Materials supplied by the contractor. Within the limits of what the supplier stands behind.
On commercial projects, standard contract forms also give the owner a period after completion, commonly one year, to report work that does not conform to the contract, and the contractor must correct it.
What it usually does not cover
- Normal cracking. Concrete shrinks as it dries and cracks somewhere. Joints control where; hairline cracks within a panel are expected and are not a defect.
- Settlement from the ground. If the soil or base was provided by others, or water undermines it later, the slab will follow it down.
- Overloading and misuse. Loads heavier than the design, impacts, or vehicles on the slab before it reached strength.
- Deicers and chemicals. Damage from ammonium-based deicers, or from salt used on new concrete against the contractor’s guidance.
- Lack of maintenance. Joints left unsealed, drainage problems left unfixed.
Questions to ask before you sign
- How long is the warranty, and when does it start?
- What exactly is covered, and what is excluded?
- How will flatness, strength and other specs be tested and documented at completion?
- How do you report a problem, and how quickly will someone respond?
- Does the warranty transfer if the property is sold?
Cracks: defect or normal?
A crack is more likely to be a warranty issue if it is wide and growing, if one side has moved up or down relative to the other, or if it runs through an area where the joints were cut too late or too shallow. Hairline cracks along or near joints, or fine surface crazing, usually are not. If you are not sure, photograph it with a coin or a tape for scale and send it to the contractor while it is small.
The best guarantee is a well-built slab
Most warranty claims trace back to a few things decided before and during the pour: the base, the joint layout and timing, the mix, and the curing. A contractor who gets those right rarely has to honor a warranty. Our post on how to choose a concrete contractor covers what to check, and we document floor flatness and closeout records on every pour.
Talk to us about your project
See our commercial concrete services or send your plans and an estimator will reply within 24 hours. The American Society of Concrete Contractors, which we belong to, publishes guidance on what to expect from finished concrete.
