The new edition of DIN 18533 and what the changes mean
Starting in June 2026, the new DIN 18533 standard will take effect — providing clarity and planning certainty with flexible polymer-modified thick coatings (FPD).
DIN 18533 is the primary set of standards for waterproofing buildings against ground moisture and water. It helps designers and contractors correctly assess the effects of water, select the appropriate waterproofing system, and ensure that all details are constructed to provide long-term protection.
With the 2026‑06 edition, DIN 18533 was significantly clarified: The requirements for planning, site evaluation, detail design, and construction were tightened—and liquid-applied waterproofing materials such as PROLASTIC® 55Z were clearly incorporated into the standards.
The key changes to DIN 18533
- a more precise assessment of water exposure
- a greater focus on details such as connections and transitions
- the close integration of site evaluation and waterproofing selection
In practice, this means:
Waterproofing systems must not only be effective, but also clearly classified as compliant with standards, safely planned, and reliably installed. PROLASTIC® 55Z meets these requirements exactly. As a tested, reactive mineral-based building waterproofing system (FPD), PROLASTIC® 55Z is firmly established in DIN 18533 and allows for clear classification into the respective water exposure classes.
“PROLASTIC® 55Z meets ALL REQUIREMENTS FOR ABP IN ACCORDANCE WITH DIN 18533”
PROLASTIC® 55Z
The major changes to DIN 18533
New classification system - supplemented by DIN 4095‑1:
With the introduction of DIN 18533‑1:2026, coordination with DIN 4095‑1 has been significantly strengthened in order to establish a comprehensive and consistent basis for design. The determination of water exposure according to DIN 4095-1 is now a mandatory prerequisite for defining the water exposure class and, consequently, for selecting the appropriate waterproofing system.
Incorporation of water exposure effects
The effects from the subsoil are taken directly from DIN 4095-1 and translated into water exposure requirements for the waterproofing.
Renaming of classes
“Water exposure classes” have been renamed — the focus is now clearly on the actual stress placed on the waterproofing.
Direct Assignment
Tables clearly assign specific exposure scenarios (e.g., Scenarios 1–3 according to DIN 4095-1) to the water stress classes specified in DIN 18533.
Definition of the Design Water Level (BWS)
The design water level relevant for waterproofing is now explicitly defined with reference to the design groundwater level (BGW) according to DIN 4095-1. The higher of the design groundwater level (BGW) and the design flood level (HHW) is used.
In short:
“In summary, DIN 4095-1 serves as the primary source for determining the physical effects of water, while DIN 18533 builds on this to define the requirements for the waterproofing system.”
Additional Water Effects in the Subgrade According to DIN 4095
E-Classes Explained Simply
E1
Low Water Exposure
Soil moisture and water that does not pool. No hydrostatic pressure is exerted on the waterproofing because water in the subsoil is either bound (soil moisture) or can reliably drain away or seep into the ground.
E2-S
Significant Water Exposure Due to Standing Water
Temporary water accumulation above the design groundwater level, e.g., due to low-permeability soil layers or lateral inflow. Hydrostatic pressure may occur even if there is no “groundwater level” in the traditional sense.
E2-G
Significant Water Exposure Due to Groundwater
Components that are located below the design groundwater level in the groundwater zone or that are submerged in groundwater. Hydrostatic pressure is constantly acting on the waterproofing.
Water Stress Classes According to the New DIN 18533
The overview table provides a concise guide and recommendations — safe, practical, and compliant with standards.
PROLASTIC® 55Z stands for standard-compliant protection, long-lasting watertightness, and reliable quality on the construction site.
Additional system products for standard-compliant building waterproofing in accordance with DIN 18533
IMBERAL® DAB LF 10S
Detail waterproofing made of liquid plastic for building waterproofing, solvent-free
INTRASIT® RZ1 55HSP
Instant Sealing Mortar, fiber-reinforced, 3–50 mm
IMBERAL® RSB 55Z
Reactive, fast building waterproofing, flexible
Additional Technical Information on FPD Construction Joint Sealing