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Brisbane Waterproofers Concrete Waterproofing

Jan 17

Brisbane Waterproofing concrete

Waterproofing protects your structure and its contents from moisture, humidity, and flooding damage. Although waterproofing systems are a small part of an entire construction project, the cost of remediation can be enormous if the wrong solution is chosen or improperly installed. 

Since 1996, the waterproofing of wet areas has been regulated by the relevant Australian Standard AS:3740 (Waterproofing of Wet Areas). During the construction phase, all wet area waterproofing work must be carried out by a QBCC-approved contractor (waterproofer). As an Australian citizen, one needs to know the required regulations for waterproofing and how it works. 



Risk of water intrusion

Typically, much more water is used in concrete than is needed to hydrate the cement. This excess water occupies space in the concrete and forms a network of capillary voids. This creates channels through which water can enter the concrete when subjected to hydrostatic pressure or capillary action. The risk of water infiltration is even greater if the foundation is built at or near the water table or in areas with heavy soil that tends to carry more moisture.


Making waterproof concrete

To make waterproof concrete, waterproof admixtures are used. Admixtures reduce water penetration by decreasing the permeability and shrinkage of the concrete as it dries. 


When is waterproof concrete used?

Waterproof concrete is generally best suited for impervious structures and less critical basements less than 10 feet deep, where soil conditions are not aggressive, and the consequences of flooding are less severe. These include unfinished, simple utility spaces such as parking lots and workshops where seepage and wet spots are tolerable. 


What entails waterproof concrete?

Low material cost and ease of application are two advantages of waterproof concrete. The ready-mix manufacturer mixes a special admixture into the concrete to produce water-impermeable concrete. The time it takes to waterproof the concrete is not a concern for the general contractor.

However, if the concrete is relied upon to be impervious, special care must be taken in processing the concrete and finishing it, as well as in the selection of raw materials. Poor pouring and vibration, inadequate curing of the concrete, and inferior aggregates can lead to honeycombing, shrinkage cracking, or crazing of the structure, allowing water to penetrate the structure. In addition, the water added to the mix while the concrete is being transported can affect the permeability of the concrete. A good concrete mix and thorough quality control are essential but challenging to achieve to avoid these issues, given the project's financial and time constraints. 




Repair of waterproof concrete

All concrete gets cracks; shrinkage, temperature-induced stresses and similar problems cause cracks. Even the most minor crack is a pathway for water. Waterproof concrete admixtures help reduce cracking, but they can't eliminate it.

When waterproof concrete fails, injection is usually used. In these cases, however, it can be challenging to locate the source of the leak because the water can drift within the concrete slab or walls. Not only is this high-priced, but it can also lead to severe problems such as mould since there is no way to remove the water once it is in the concrete. Therefore, this is another reason why waterproof concrete is best suited for low-risk, unfinished spaces, as breaking up the walls for injection grouting would be tedious and expensive. In addition, especially in deep basements, it is difficult, if not impossible, to gain access to locate and repair leaks. 


When concrete waterproofing is not enough

For spaces that need to be kept dry or for utility and storage spaces or deep basements with limited tolerance to water vapour, precast waterproofing membranes are preferable to concrete waterproofing. This is because they can resist hydrostatic forces that otherwise force water into the structure. With precast waterproofing, the waterproofing barrier is applied before the concrete slab and walls are poured. 

The concrete is then poured onto the membrane, forming a bond that keeps water and moisture out. 

The membrane essentially compensates for structural failures for fully adhered, precast waterproofing. For example, the waterproofing membrane should remain on the concrete if gaps form due to floor subsidence. In addition, repairs should be minimal due to the strength of the bond between the concrete and the waterproofing membrane. This bond prevents water from seeping in laterally. Therefore, it is easier and less expensive to isolate and repair than concrete waterproofing if a leak occurs. 




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