Roof Rehabilitation


BORNIT® Bitumen Mastic

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BORNIT® Bitumen Mastic
Bituminous filler compound for surfaces and end seals;  UV-resistant, good adhesion to concrete, masonry, plaster,  bituminous surfaces and metal substrates. For sealing coving joints along chimneys and wall transitions, crack-bridging, water-tight, contains solvent, workable down to -5°C. Prime with BORNIT® Bitumen Primer. Tested in compliance with AIB.

Colour: black

4 017228 003795
4 017228 003641
4 017228 003658
4 017228 003665
1 kg
2,5 kg
6 kg
12 kg
18 cans/box
99 bucket
75 bucket
45 bucket
approx. 1.2 kg/m² per mm layer thick-ness
 BORNIT®-Kaltspachtel - 12 kg

detailed information

Areas of application
BORNIT® Bitumen Mastic is used for repair and waterproofing of defects in roofing membranes of bituminous roof sheeting as well as junctions and edges of penetrations, installed components, etc. The product adheres well to mineral substrates (concrete, plaster, masonry), bituminous roof sheeting and coatings as well as fibre-cement surfaces. Application on non-absorbent substrates, like non-ferrous metals and steel, should only be undertaken after priming and with a maximum pitch of 25° (approx. 50 %) and maximum layer thicknesses of 4 mm in order to avoid running off.
Not suitable for plastic sheeting, polystyrene or rigid foam substrates as well as impregnated surfaces, e.g. treated with silicone-containing coatings.
Prior to application on concrete, masonry and plaster, the substrate must be primed with BORNIT® Bitumen Primer for dust binding.

Type and properties
BORNIT® Bitumen Mastic is a paste-like, fibre-reinforced bituminous sealing compound for cold application. The solvent-containing product is resistant to non-oxidising acids and contains stabilising additives to prevent settling. The material properties only become fully effective following complete and thorough drying. Then, the filling compound is water-impermeable and resistant to adverse weather conditions. It is not resistant to solvents, fuels, oils and oxidising acids. BORNIT® Bitumen Mastic is free from tar, asbestos, PCK and PCB. Tested according to AIB DS 835.

Product advantages
• Manufactured ready for processing
• Crack-bridging, waterproof and UV-resistant
• Universally applicable
• Low equipment and material costs and effort during processing

The substrate must be dry, clean, oil- and grease-free as well as stable. For better adhesion on concrete, masonry or plaster, BORNIT® Bitumen Primer is recommended for priming.
The primer must be completely dry before applying the filling compound.
The product contains solvents, which may damage synthetic materials, etc. Check compatibility with the substrate prior to application!

BORNIT® Bitumen Mastic is manufactured ready for processing and is applied directly as delivered with a trowel or spatula. In case of cold weather, store the filling compound in a heated room prior to processing.
BORNIT® Bitumen Mastic is best processable at temperatures between +5 °C and +35 °C. With previous warm storage, processing, however, is possible down to an outside temperature of -5 °C.
Intensively spread the product onto the substrate, tapering out at the edges.
In that, application thicknesses of up to 5 mm are possible. Only apply thicker compound layers in several work steps with a time interval inbetween, enabling secure and uniform evaporation of the solvent! Otherwise, blistering due to solar irradiation and very long (several weeks) drying times cannot be excluded. Do not apply to heated or easily heatable substrates.
During drying, protect the coating from moisture, rain or condensation water.

Approx. 1.2 kg/m² per mm of layer thickness

Product data in brief

Type Bituminous smoothing compound
Base bitumen, solvent, aggregates
Solvent white spirit
Colour black
Density approx. 1.20 - 1.30 g /cm³
Consistency pasty-like
Application With a spatula
Softening point of solids (SP) +160 °C
Heat resistance at +70 °C No running off
Water permeability 0.5 bar, 8 h Impermeable
Storage Not sensitive to frost
Shelf life In originally sealed containers 12 months. Keep away from ignition sources!
Cleaning BORNIT® MultiClean, BORNIT® Bitumen Cleaner
Acc. to. Industrial Safety Regulation (BetrSichV) flammable
GISBAU product code BBP 20
VOC content < 230 g/l


System products
BORNIT® Bitumen Primer

The product can be stored for 12 months in the original sealed container. Sensitive to frost!

Health and fire protection, occupational safety
For information on handling, safety and ecology, please refer to the current safety datasheet.

Forms of delivery
1.0 kg  can…………………………………………..    18 cans per box
2.5 kg   bucket…………………………………….    99 containers per pallet
 6.0 kg  bucket…………………………………….    75 containers per pallet
12.0 kg bucket…………………………………….    45 containers per pallet

Note on disposal
Only recycle completely empty containers. Material residues can be disposed of according to AVV-ASN: 080409* (adhesive and sealing compound residues containing organic solvents or other hazardous substances).

This datasheet replaces any previous technical information about the product. Thus, this information is no longer valid. The details have been compiled according to the latest state of application technology. Please observe, however, that, depending on the state of the construction object, deviations from the method of application suggested in the datasheet may be required. Unless agreed otherwise in individual contracts, any information contained in the datasheet shall be non-binding and thus does not represent an agreed product constitution. We reserve the right to changes in the information contained in this datasheet anytime.


Note technical rules!


Necessary information – particularly for the use and the use of our products – please refer our brochures. We are at your personal disposal.