How to chooce the right pre-applied waterproofing membrane?

In the waterproofing sector of the commercial construction market, one of the most frequently asked questions is, “What is the best waterproofing product?”

“There is no ‘best’ waterproofing product.” We have to look for the most suitable waterproofing design and combine the most siutable products to a waterproofing system. A below grade structure is mostly a concrete structure with additional joint sealing systems and waterproofing components. This watertight concrete structure is additionally sealed with a pre-applied waterproofing membrane to seal the concrete cracks, to improve the life-time of the structure, to improve the durability of the concrete in case of aggressive ground water or even salt water and last but not least to avoid any ground-gas penetration into the building such as radon gas. This looks like additional cost, but the advantage is the life-time, the durability of the structure and no unexpected cost risk due to concrete crack injection which can cost in the end more than a well-designed external pre-applied waterproofing membrane system.

To ensure the concrete is workable on site, most concrete contains more water than is required to simply hydrate the cement. As this concrete sets and hardens, this excess water leaves the concrete and creates a network of fine cracks and internal pores which act almost like a sponge. A waterproofed concrete should have a w/c-Ratio (water/cement) of not more than 0.5 - but on site the concrete normally contains more water.

This is the major argument to use additionally a pre-applied concrete bonding membrane to improve the waterproofing result of below grade concrete structures exposed to pressurized water.

Because concrete is an inherently porous material it can never be 100% waterproof and gas tight. If we talk about gas tightness we talk about the natural ground gas radon. Both, water tightness and radon gas tightness can be achieved by an external pre-applied concrete bonding membrane.

To achieve the top level of water tightness and radon gas tightness for a given application, the following factors need to be considered:

1. Appropriate material selection and suitable concrete mix design (water/cement ratio not more than 0.5)
2. Adequate structural- and waterproofing design, construction joints / expansion joints / formwork ties / penetrations / waterproofing design and pre-applied waterproofing membrane
3. High quality construction and high quality workmanship on site
4. The right choice of the pre-applied concrete bonding waterproofing membrane (easy handling on site / workability depending on high and low temperature / good concrete adherence (mechanical adherence)

What is the right pre-applied waterproofing membrane for you?

What is more siutable a pre-applied waterproofing membrane with a mechanical bonding / mechanical adhesion or a membrane with only an adhesive bonding / adhesive layer?