Concrete Shopper helps source a waterproof concrete mix for slabs and walls when your engineer specifies reduced-permeability requirements.
Use this type of concrete when the project specification requires reduced water penetration through the concrete element. It may suit certain below-ground slabs, retaining or basement walls, tanks and other moisture-exposed structures, but it does not make poor design or workmanship watertight.
When Is a Waterproof Concrete Mix Appropriate?
“Waterproof concrete” is a convenient market term. In technical specifications, the requirement may instead refer to low-permeability concrete, a permeability-reducing admixture or a complete watertight concrete system.
A waterproof concrete mix may be considered for:
- Below-ground slabs and walls: Where soil moisture or groundwater exposure forms part of the engineered design.
- Water-retaining structures: Where a designer specifies concrete properties, joints and testing for a tank or similar structure.
- Difficult-to-access surfaces: Where repairing or replacing an external waterproofing layer later would be disruptive.
- High-moisture service areas: Where reduced permeability is required as one part of the moisture-management system.
- Reinforced coastal structures: Where the engineer specifies concrete durability measures for the relevant exposure conditions.
The application alone does not determine the mix. Structural loads, exposure classification, crack control, joints, penetrations, drainage, surface treatments and regulatory requirements must be resolved by the appropriate designer or engineer.
Does the Mix Replace Waterproofing Membranes?
Not automatically. A permeability-reducing admixture can restrict moisture movement through sound concrete, but water can still travel through cracks, poorly compacted areas, construction joints and unsealed penetrations. Bathrooms, balconies, roofs and other regulated wet areas may still require a separate waterproofing system.
The Cement Concrete & Aggregates Australia admixtures guide explains that admixtures are added in controlled quantities to modify concrete properties. Their effects can depend on the other mix constituents, temperature and interactions with additional admixtures. This is why the specified product, dose and performance criteria should be confirmed with the engineer, admixture provider and concrete supplier.
Our article on permeability-reducing concrete additives explains these limitations in more detail. Treating an admixture as an automatic cure for every leak is bad specification practice.
What Must Be Confirmed Before Ordering?
Do not order by asking only for “waterproof concrete”. Provide the batching plant with the documented mix requirements so it can confirm availability and pricing.
Your order information may need to cover:
- specified strength grade and exposure requirements
- nominated admixture or performance criteria
- required slump, aggregate size and placement method
- total volume and allowance for the pour
- testing, certification or delivery-docket requirements
- site access, truck spacing and requested arrival time
- compatibility with other specified admixtures.
The engineer, builder and waterproofer should also agree on reinforcement, joint details, penetrations, compaction, finishing and curing. Our guide to concrete slab timing explains why weather, placement and curing preparation matter even when a specialist mix is ordered.
Source the Specified Mix Through Concrete Shopper
Concrete Shopper works with ready-mix suppliers across Australia and helps customers compare suitable supply options. We can discuss strength, quantity, location, delivery and additive requirements, but we do not replace the project engineer or waterproofing designer.
If your documents nominate a waterproof concrete mix, send us the specification, site postcode, required volume, pour date and placement details. Use our ready-mix concrete order form or contact us for a quote, and we will check suitable supplier options for your project.