Curing Concrete in a Saudi Summer: The Mistakes That Weaken a Structure

Curing is the cheapest quality step on site and the first one dropped when the programme tightens. These are the failures it causes and how each one is prevented.

Concrete gains strength through hydration, and hydration needs water. In dry heat with wind, a freshly placed slab can lose surface water faster than it rises as bleed water, and the surface then cracks and under cures before it has meaningful strength. The damage is permanent: a surface that did not cure stays weaker, more porous and less durable for the life of the building. These are the recurring curing failures and what closes each one.

Why these keep happening

Curing fails because it belongs to nobody. The pour team finishes and leaves, the next trade has not started, and the element sits unattended through the hottest part of the day. Everyone assumes someone else sprayed it. Making curing a named activity with a named person and a daily record converts it from an afterthought into a controlled process, and it costs very little compared with the surface repairs it prevents.

1. Starting curing too late

The critical window is immediately after finishing, when the surface is most vulnerable to evaporation. Waiting until the end of the shift, or until the following morning, means the surface has already dried, cracked and lost the water the cement needed. On a windy day the window is measured in minutes, not hours.

• Avoid it by: Start protective measures as soon as the surface can take them, using fog spraying or an evaporation retarder between finishing operations.
• Proof it is closed: A curing log with the time curing commenced for each element, signed by the site engineer.

What it costs you: Plastic shrinkage cracks across the slab, a dusting surface, and a repair that is cosmetic at best.

2. Treating a curing compound as a quick alternative to water

Curing compounds work by forming a film that slows evaporation, and they only work if applied at the specified coverage rate, uniformly, at the right moment, on a surface that has not already dried. Sprayed thinly over a partly dried slab they do very little, and on a surface that will later receive tiles or screed the wrong compound creates a bond breaker.

• Avoid it by: Specify the compound, check the coverage rate against the volume used per square metre, and confirm compatibility with every later finish.
• Proof it is closed: A record of product, batch, area covered and litres used, compared against the manufacturer rate.

What it costs you: Under cured concrete plus a debonded finish later, which means removing and relaying the floor covering.

3. Letting hessian or covers dry out

Wet coverings cure well while they are wet. Once they dry they stop working and can actively draw moisture out of the surface. In summer, hessian laid at eight in the morning is bone dry by mid morning unless someone keeps rewetting it, and nobody is scheduled to.

• Avoid it by: Assign a curing operative per zone with a rewetting schedule, or use a system that holds water such as wet hessian under plastic sheeting.
• Proof it is closed: Daily photographs and a signed sheet showing rewetting times through the curing period.

What it costs you: Patchy curing, with strength and durability varying across a single element.

4. Stopping curing when the formwork comes off

Vertical surfaces are protected by the formwork while it is in place, and the moment it is struck they are exposed to sun and wind at a very young age. Columns and walls in summer frequently get no curing at all after striking, because the team associates curing with slabs.

• Avoid it by: Extend curing to vertical elements immediately after striking, by wrapping, spraying or leaving forms loosened in place and watering between form and concrete.
• Proof it is closed: The curing log covers columns and walls, with a start time tied to the striking time.

What it costs you: Surface crazing, low surface strength and increased permeability where cover concrete protects the reinforcement.

5. Curing for a fixed number of days regardless of conditions

The duration needed depends on the cement type, the mix, the element and the weather. Blended cements gain strength more slowly and need longer protection. Applying a habitual period to every element means some are cured longer than necessary and others are exposed before they are ready.

• Avoid it by: Take the duration from the specification for the mix and element, and extend it in extreme conditions on the engineer instruction.
• Proof it is closed: A curing schedule by element type and mix, approved by the supervising engineer.

What it costs you: Under cured elements in the worst conditions, exactly where the risk is highest.

6. Loading or working on concrete that is still curing

Storing blocks on a young slab, propping the floor above from it or letting trucks run over it applies load the concrete cannot yet carry. Damage from early loading is often invisible as cracking but shows up as deflection and as reduced capacity in the element.

• Avoid it by: Set a minimum strength or age before loading, based on the engineer back propping and loading criteria, and control material storage positions.
• Proof it is closed: Loading approval recorded against cube results or maturity data rather than against the calendar.

What it costs you: Permanent deflection, cracking around load points and in the worst cases a structural assessment and strengthening.

7. Ignoring wind as a separate risk

Evaporation from a concrete surface is driven by temperature, humidity and wind speed together, and wind is often the dominant factor. A moderate temperature with strong dry wind can be worse than a hot still day, which surprises teams who only check the thermometer.

• Avoid it by: Use windbreaks around open pours, schedule around forecast wind, and apply evaporation retarders when conditions warrant.
• Proof it is closed: Weather conditions recorded with each pour, including wind, not only temperature.

What it costs you: Plastic shrinkage cracking on days the team considered safe.

A short check before you sign

• Curing is a named activity on the programme with a responsible person per zone.
• The curing method and duration for each element type are stated in an approved method statement.
• A curing log records start time, method, rewetting and finish for every element.
• Curing compound coverage is verified by litres used against area covered.
• Vertical elements are covered by the regime immediately after striking.
• Loading of young concrete is controlled by a stated strength or age criterion.

If it has already happened

If an element has clearly been under cured, start by establishing what the concrete actually achieved rather than assuming the worst. Compare cube results, consider non destructive testing across the affected area and take cores where the evidence is unclear. Where the shortfall is confined to the surface, which is the usual case, the practical issues are durability and the bond of later finishes, so options include applying a penetrating treatment, removing and replacing the weak surface layer, or changing the finish specification to one that tolerates the substrate. Where testing indicates the shortfall reaches into the section, it becomes a structural question for the designer. In every case, record the event and the remedy, because an undocumented curing failure becomes an unanswerable question during a future sale or insurance claim.

Domira builds and supervises projects across Saudi Arabia, and this is the level of detail its site teams work at. Send the drawings or the site, and Domira will tell you what the specification has to say before anyone prices it.