Waterproofing for indoor applications - Part 4: Waterproofing with mastic asphalt or asphalt mastic
1Key Takeaways
This draft standard specifies the design, construction, and maintenance requirements for indoor floors using cast asphalt or asphalt mastic waterproofing layers, with a maximum water accumulation height of 10 cm.
2Expert Interpretation
The draft German standard DIN 18534-4 specifies in detail the technical requirements for waterproofing interior spaces using poured asphalt or mastic asphalt, including material selection, construction techniques, joint treatment, and acceptance criteria. It is applicable to indoor floor waterproofing projects with a maximum water accumulation height of 10 cm.
DIN 18534-4 Standard Overview and Technical Evolution
DIN 18534-4, as an important component of the German building waterproofing standard system, specifically provides technical specifications for waterproofing projects using cast asphalt and bitumen mastic in interior spaces. The draft standard, released in September 2016, is intended to replace the existing DIN 18195 series of standards and reflects the latest developments in German building waterproofing technology.
Scope of application and restrictions of the standard
This standard applies to indoor floor waterproofing projects, with a maximum allowable water accumulation height of 10 cm. Applicable base materials include: concrete in accordance with DIN EN 1992-1-1, cement-based self-leveling mortar in accordance with DIN 18560, and insulation layer (applicable only to waterproofing structures combining cast asphalt and asphalt welded membranes).
| Waterproofing material type | Applicable waterproofing grade | Applicable crack grade | Minimum thickness requirement |
|---|---|---|---|
| Poured asphalt | W0-I | R1-I to R2-I | 25mm |
| Mastic asphalt | W0-I | R1-I (without isolation layer) | 7mm |
| Composite waterproofing system | W0-I to W3-I | R1-I to R3-I | Multi-layer combination |
Material technical requirements and performance indicators
The standard puts forward clear technical requirements for waterproofing materials: Poured asphalt screeds must comply with DIN EN 13813, mastic asphalt must meet DIN EN 12970, and polymer asphalt welding membranes must use a polyester non-woven fabric as a carrier material and comply with DIN V 20000-203. Key performance indicators include: stability, fire resistance, alkali resistance, crack bridging (crack bridging capacity, at least 2.0 mm), and water resistance. All materials must pass these performance tests before they can be used in construction. Construction Process and Quality Control Requirements: Substrate Preparation Requirements: The substrate must be dry, and the surface temperature during construction must be at least 3K above the ambient air dew point. Strict control of construction environmental conditions is required to prevent condensation and the formation of an insulating water film.
Poured Asphalt Construction Process
The poured asphalt layer should be between 25-40mm thick and applied using a scraper or push-paving machine. Larger areas can be covered mechanically. During interruptions, cold joints should be heated indirectly with a tool and hot materials added to create a seamless joint.
Asphalt Mastic Application Requirements
The average thickness is 10mm, with no thickness less than 7mm or exceeding 15mm at any point. Application can be over a fiberglass insulation layer or asphalt primer. The primer must be completely dry before applying the mastic layer.
Detailed Joint Treatment Techniques
Wall Joint Treatment
Wall joints should use the materials specified in Sections 7.2 and 7.3c, and should be applied in a single layer with an overlap of 100mm in accordance with DIN 18534-2. A grouting joint should be provided between the poured asphalt and the waterproofing material.
Treatment of penetrations
Penetration connections are also constructed with a single layer of 100mm overlap, and grouting is used to ensure sealing integrity.
Waterproofing of expansion joints
Waterproofing is carried out by installing suitable joint profiles, and the joints are treated with 300mm polymer bitumen welded membranes or liquid plastics as specified in Clause 7.2.
Classification and application guide for waterproofing systems
| Waterproofing system type | Structural level | Applicable environment | Special requirements |
|---|---|---|---|
| Single poured asphalt system | Isolation layer + poured asphalt | Ordinary indoor environment | Thickness control 25-40mm |
| Single asphalt mastic system | Primer/Isolation layer + mastic | Slightly humid environment | Average thickness 10mm |
| Composite waterproofing system | Multi-layer material combination | Moderate to severe humid environment | Chemical stability requirements |
Acceptance and maintenance requirements
Strict acceptance inspection is required after the completion of the waterproofing project. The poured asphalt waterproofing layer can be used immediately after cooling (2-4 hours depending on thickness), but should be protected from water until this point. The asphalt mastic layer can also be used after cooling.
Maintenance: Cracks and defects in the poured asphalt or asphalt mastic must be heated using a tool (such as a replaster) and filled with repair material. For waterproofing systems that combine poured asphalt with polymer asphalt welded membranes, cracks wider than 2mm can be repaired using a suitable reaction resin and, if necessary, nailed into the cracked area.
Standard Implementation Recommendations and Precautions
In actual engineering applications, it is recommended to focus on the following aspects: First, strictly select qualified materials according to standard requirements and ensure that all materials have the corresponding certifications; second, strictly control environmental conditions during construction, especially the relationship between substrate temperature and dew point temperature; third, detailed joint treatment must be carried out in accordance with standard requirements to ensure the integrity of the waterproofing system.
It is particularly important to note that this standard must be used in conjunction with DIN 18534-1, which provides general regulations and requirements for waterproofing projects. At the same time, all diagrams in the standard are schematic representations, and detailed design is required according to specific circumstances in actual projects.
For special use environments, such as chemical plants and laboratories where chemical corrosion may occur, additional verification of the chemical stability of the waterproof material is required to ensure long-term performance.