ABC of General Requirements for Substrates 🤓

When planning to build a house, it's essential to understand the requirements a substrate must meet to ensure technically correct insulation.

While this might not be the first thing on your mind when preparing for construction, it's worth noting that one of the most common reasons waterproofing fails to function effectively is the lack of a properly prepared substrate.

Substrate Requirements:

1. Dimensional Tolerances of the Substrate
   • a) Newly built walls/structures must meet the dimensional tolerances permissible by ITB standards.
   • b) Existing walls/structures are not required to meet dimensional tolerance standards.
   • c) Tanking-type waterproofing: sealing is applied directly to the structural element.
   • d) Ground floors: it is recommended to prepare the substrate to meet dimensional requirements (ITB standards, alternatively DIN18202 norms, or "Toleranzen im Hochbau" guidelines).
2. Moist or Wet Substrates
   • Substrates are typically damp or even wet—most modern waterproofing materials tolerate matte-damp substrates (without standing water).
3. Highly Saturated Substrates
   • These can be pre-sealed, for instance, with a mineral slurry.
4. Stability and Load-bearing Capacity
   • Substrates must be stable, load-bearing, and free of cracks.
5. Cleaning and Assessment
   • Exposed/dug-out elements must be thoroughly cleaned and assessed. Loose masonry fragments, crumbling, and saline joints must be removed, as well as any materials affecting waterproofing adhesion. Heavily saline walls should be cleaned mechanically, and the use of desalination agents should be considered.
6. Cavities and Defects
   • Cavities, grain nests, and voids should be filled with system-specific repair mortars.
7. Edge Preparation
   • Outer foundation edges must be rounded or chamfered. Internal corners should be rounded (a fillet) using a system-specific mortar.
8. Press Layer
   • On horizontal surfaces waterproofed with bituminous materials, a press layer should be applied.
9. Structural Application
   • Coating-type waterproofing must be applied to the structural elements of the building.
10. Sealing Points and Lines

• Point and linear water leaks must be sealed before applying waterproof coatings.

Properly preparing the substrate ensures the long-term effectiveness of your waterproofing solution.

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