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DIN 18531 Guide & Solutions

As the successor to DIN 18195 (2017), DIN 18531 regulates the waterproofing of roofs, balconies and loggias - including requirements, effects and implementation principles for used and unused surfaces.

What does DIN 18531 regulate?

DIN 18531 specifies requirements for the planning, selection and execution of waterproofing for roofs (unused & used) as well as balconies, loggias and arcades. It is based on the application classes K1 (standard) and K2 (higher quality) as well as the exposure classes from mechanical (I = high, II = moderate) and thermal stress (A = high, B = moderate) - combined to IA, IB, IIA, IIB.

Note: The standard consists of

  • Part 1 (requirements/planning roofs) ,
  • Part 2 (Materials) ,
  • Part 3 (selection/design/details) ,
  • Part 4 (Maintenance) ,
  • Part 5 (balconies/loggias/porches).
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Brief overview of use & gradient

Category Description
Unused roofs Only accessible for maintenance/care; extensive green roofs are included here.
Used roofs Walkable (e.g. terraces, walkways) or intensively greened roofs; special layer structures/drainage.
Slope Regularly ≈ 2 % as a planning target; deviations require increased measures and generally higher quality design.generally higher quality design.

K1/K2 & Impact (IA-IIB)

Application classes Effect classes
K1 - standard design (typical requirements, gradient ≈ 2% as target) IA - high mechanical + high thermal impact
K2 - higher quality design (e.g. increased use, technology/equipment, demanding impacts) IB - high mechanical + moderate thermal impact
  IIIA - moderate mechanical + high thermal impact
  IIIB - moderate mechanical + moderate thermal impact

Planning & execution (Essentials)

  • Slope & drainage - slope planning, emergency drainage, avoiding accumulation/ponding
  • Impact - walking/driving on, superstructures/building services, thermal loads (e.g. risk of shattering)
  • Details - connections/terminations, edges, upstands; solve penetrations in a standardized way
  • Use - Correctly layer coverings/drainage/protective layers for used areas
  • Maintenance - Regular maintenance/documentation in accordance with Part 4

Note: The original standards DIN 18531-1/-2/-3/-4/-5 and the manufacturer's system documents (ETAs/EADs, installation instructions) are binding.

Application area Suitable designs / notes
Unused roof
K1 (usually slope ≈ 2%)
  • Membranes (bitumen/polymer bitumen; plastic/elastomer) in accordance with Part 2
  • Liquid plastic systems according to Part 2 (ETA/EAD-based) with fleece inlay
  • Penetrations/connections with system accessories - provide maintenance routes
Unused roof
Slope < 2 % or 0 %
  • Higher-quality design (often K2); check drainage/emergency drainage in particular
  • Slope insulation/detail slope, reinforced layer concepts
Used roof
Terraces, intensively greened roofs
  • Layered structure with separation, protection and drainage layers; functional linear/point drainage
  • Waterproofing in sheet form or liquid applied - details in accordance with Part 3
Balconies/loggias/porches
Part 5
  • Membrane or liquid plastic construction types; composite coverings possible (per system)
  • Note upstands/connection heights, drainage, slip resistance, transitions (e.g. door thresholds)

K1 stands for standard requirements, K2 for higher-quality design (e.g., higher stress, technology, special use). The selection influences, among other things, the number of layers, material quality, and detail design.

In justified cases, slope-free planning may be possible – this usually requires higher-quality execution and special measures. The standard is a planning slope of approx. 2%.

Bitumen/polymer bitumen and plastic/elastomer membranes, as well as liquid plastics with ETA/EAD certification. Selection depends on use, exposure class, and detailed requirements.