About Integral Waterproofing
Integral waterproofing goes INSIDE the concrete. Membrane waterproofing has a number of issues. It can be expensive, time-consuming, and easy to damage. Most membranes are made using oil-based materials and are not sustainable. If they leak, it’s not obvious who caused the problem and there can be a lot of finger-pointing. See risk reduction to learn more about the benefits of integral waterproofing over membrane waterproofing.
Integral waterproofing can be a far better solution than membranes for a number of reasons:
- Faster construction
- Reduced cost
- Reduced risk with a performance warranty
- Greener construction
- Simple details
Integral waterproofing solutions all work by blocking water from being able to get into concrete, which is usually a water-loving material that sucks up moisture. Not all integral waterproofing solutions are the same – waterproofing admixtures vary in terms of performance, health and safety, service, and warranty.
Hydrophobic admixtures absorb less than 1% of water, and give superior performance compared with densifying admixtures. They considerably reduce the amount of water absorbed by dry concrete, and also protect against further water ingress when concrete is wet. They also protect against water ingress from hydrostatic pressure.
Water-Based Hydrophobic Permeability Reducing and Pore Blocking Admixture
Hycrete admixtures work by forming barriers in the concrete matrix, which stop water from getting in through capillaries. They also coat reinforcing steel, protecting against corrosion. For more information, see How Hycrete admixtures work.
- Low dosage required – 1-2 gallons per cubic yard
- Cradle to Cradle Certified
- May be used in conjunction with fly ash and slag
- Service and warranty with Hycrete System W
- Directly protects against corrosion
Ammonia Emulsion Admixture – Caltite
These hydrophobic admixtures consist of tiny “rubber balls” held in suspension in an ammonia solution. The rubber balls block the capillaries in the concrete, reducing the potential to absorb water.
- High dosage required – 6 gallons per cubic yard
- Service and warranty provided by manufacturer
- Does not directly protect against corrosion
Densifiers may reduce the permeability of concrete. They tend to work best in situations where the concrete is permanently saturated, and less well where drying and rewetting may occur.
Supplementary Cementitious Materials
Fly ash, slag, and silica fume are industrial by-products: Fly ash comes from electricity production using coal as a fuel; slag is a by-product of steel manufacture; and silica fume comes from silicon manufacture. They are all ground very fine, and when they are used in concrete mixes they fill in gaps in the concrete structure to reduce permeability.
|Fly ash – from electricity production using coal||Slag – from steel manufacture||Silica fume – from silicon manufacture|
- May be used with other densifiers and hydrophobic admixtures
- Generic, non-branded materials, readily available
- Reduce permeability
- Will not (on their own) provide a waterproof structure
- No warranty or service
- Do not directly protect against corrosion
Treated Silicates – “Crystal Growth”
Crystalline waterproofing admixtures are composed of cement, treated silicates, and other unidentified chemicals. These are generally already basic components of concrete, and work to “densify” concrete by reducing pore size. They work by forming crystals within the concrete capillaries – these could be compared to a beaver dam made out of sticks but no mud – limited effectiveness. In fact, it is possible that they may increase the absorption of water because of capillary action in the narrower holes. Imagine sucking water up through a straw – it takes a lot less pressure and effort to suck water through a thin straw than through a thick straw. For this reason, concrete with crystalline admixtures may have higher absorption than control concrete. Manufacturers include Xypex, Kryton, Ipanex, Penetron and Aquafin.
Like all products, integral waterproofing is more suited to certain applications.
When comparing integral waterproofing products, here are some questions to ask:
Concrete Durability – Understanding Water Transport Mechanisms in Concrete
Please contact us with any questions you have about integral waterproofing.