Moisture-variable diffusion inhibiting layers

Moisture-variable diffusion-inhibiting layers are films regulating moisture. They are used, for example, in flat-sloping or pitched, fully insulated, non-ventilated roof constructions with metal roofing or waterproofing on formwork or planking and ensure that moisture that has penetrated can be released again.

Regulatory framework

For construction products used as moisture-variable diffusion inhibiting layers, DIBt grants national technical approvals (abZ) because

  • neither Technical Building Rules (cf. MVV TB Chapter C 2) nor generally recognised technical rules exist.

European Technical Assessments (ETAs) can also be issued for these construction products.

For construction techniques comprising construction products used as moisture-variable diffusion inhibiting layers, DIBt grants general construction technique permits (aBG) when there is no conclusive technical rule for design and execution.

Moisture-variable diffusion-inhibiting layers are provided for in DIN 68800-2:2012-02, Section 7.5 for certain constructions to protect the timber and ensure long-term stability. The layers must regulate moisture on a permanent basis. Technically speaking, this special property is achieved by means of a moisture-variable diffusion resistance.

Application forms

National procedure

A national technical approval (abZ) and/or oder general construction technique permit (aBG) is granted upon application (see Model Building Code (MBO), Sections 16a(2) and18(2) and (4)). This also applies to amendments and supplements to, or renewals of existing approvals and/or construction technique permits.

No formal requirements apply. The following information is needed: name and address of the applicant, description of the product and/or construction technique and its field of use or application, type of decision required (new decision, amendment or supplement to, or renewal of, an existing decision).

Please feel free to use the template below.

Application for a national technical approval and/or construction technique permit (3 pages)

Version: January 2018; Application form

Application for amendment / supplementation / renewal of a national technical approval and/or construction technique permit (4 pages)

Version: January 2018; Application form

Guideline: How to provide drawings for national technical approvals and general construction technique permits (5 pages)

Version: July 2017

European Technical Assessment (ETA)

To start the ETA procedure, please submit the form below. We will then check if the prerequisites for issuing an ETA are met, i.e., in particular, if the product is not fully covered by an existing harmonised standard. If the prerequisites are met, we will check whether a European Assessment Document (EAD) covering the requested assessment scope already exists or still needs to be developed. If an EAD needs to be developed or amended, a complete technical file needs to be established before the procedure can begin.

Form for requesting a European Technical Assessment (ETA) (2 pages)

Last updated: September 2021

  • abZ/aBG
  • ETA
  • Z = new decision | E = supplement | Ä = amendment | V = renewal | G = valid until
    Subject concerned Applicant Decision no. Validity
    from / to
    Feuchtevariable Dampfbremsbahn "Vario® KM Duplex UV"

    SAINT-GOBAIN ISOVER G+H AG

    Bürgermeister-Grünzweig-Straße 1

    67059 Ludwigshafen

    Z-9.1-871 Z: 09.08.2018
    G: 16.02.2023
    Feuchtevariable Dampfbremsbahn "Vario® XtraSafe"

    SAINT-GOBAIN ISOVER G+H AG

    Bürgermeister-Grünzweig-Straße 1

    67059 Ludwigshafen

    Z-9.1-872 Z: 09.08.2018
    G: 16.02.2023
    Feuchtevariable Dampfbremsbahn ALUJET Climajet SD VARIO

    ALUJET GmbH

    Ahornstraße 16

    82291 Mammendorf

    Z-9.1-879 Z: 20.03.2018
    G: 20.03.2023
    Feuchtevariable Dampfbremsbahn "TargoVARIVAP N"

    Targo Specialty Products AG

    Brüelstraße 23

    8932 METTMENSTETTEN

    SCHWEIZ

    Z-9.1-881 Z: 30.01.2019
    G: 30.01.2024
    Feuchtevariable Dampfbremse "URSA SECO SDV"

    URSA Deutschland GmbH

    Carl-Friedrich-Benz-Straße 46-48

    04509 Delitzsch

    Z-9.1-883 Z: 29.10.2018
    G: 29.10.2023
    Feuchtevariable Dampfbremsbahn "Superbran Trio"

    SUPERGLASS DÄMMSTOFFE

    Industriestraße 12

    64297 Darmstadt

    Z-9.1-884 Z: 25.09.2018
    G: 25.09.2023
    Feuchtevariable Dampfbremsbahn Knauf Insulation LDS FlexPlus

    Knauf Insulation GmbH

    Heraklithstraße 8

    84359 Simbach am Inn

    Z-9.1-888 Z: 22.03.2019
    G: 22.03.2024
    Feuchtevariable Dampfbremsbahn ALUJET Climajet SD VARIO

    ALUJET GmbH

    Ahornstraße 16

    82291 Mammendorf

    Z-9.1-891 Z: 27.06.2019
    G: 27.06.2024
  • Subject concerned Applicant Decision no. Issued on
    Humidity-dependent vapour control layers INTELLO and INTELLO PLUS

    MOLL bauökologische Produkte GmbH

    pro clima

    Rheintalstraße 35-43

    68723 Schwetzingen

    DEUTSCHLAND

    ETA-18/1146 28.11.2019

Anja Dewitt
Head of Section – Timber Construction

Phone +49 30 78730-317
Email adw(at)dibt(.)de

Legal reference documents

Testing, certification, inspection