BORNIT® Siloflex

bitumen | silo | silo protection | silo sealing | solvent-free | quick-drying | JGS
short information
  • reliable bitumen protection
  • without solvents
  • economical alternative to synthetic resin coatings
  • 1-component - no mixing necessary
  • with reduced surface tackiness
  • quick drying, brushable and sprayable
  • economical processing from large containers (180 kg barrel)
  • resistant to organic acids, salts and alkalis
180 kg / barrel
sufficient for:
EAN code
euro pallet
approx. 360 m²
4 017228 00311 5
2 barrel
25 kg / bucket
sufficient for:
EAN code
euro pallet
approx. 50 - 62.5 m²
4 017228 00310 8
18 bucket
approx. 0.45 kg/m² per coat (3 coats required)
storage note
  • sensitive to frost!
  • in originally sealed containers storable for 12 months


Wetting tools with water before and during use considerably extends their service life!

status technical data sheet
26 March 2021

areas of application
BORNIT® Siloflex protects mineral substrates, such as concrete, plaster and masonry, against moisture, and thus from destruction. BORNIT® Siloflex is used as a protective coating for concrete in feedstuff silos, septic tanks, manure channels and in stables (not for direct long-term contact with animals). BORNIT® Siloflex is a well-covering protective coating against aggressive wastewaters as well as numerous chemical substances, such as alkalis, organic acids and salts.
Not suitable for use in biogas plants. For better adhesion on mineral substrates, use BORNIT® Siloflex Primer or BORNIT® Siloflex diluted with water 1:1 (add water under stirring), resp., as a primer.

type and properties
BORNIT® Siloflex is a solvent-free, single-component bitumen coating, drying into a seamless, elastic and liquid-proof sealing layer. Due to its thixotropic consistency, BORNIT® Siloflex can be brushed or sprayed onto vertical surfaces without any problem. BORNIT® Siloflex is resistant to liquid manure and wastewaters from fermentation and sewage treatment processes. BORNIT® Siloflex has a building authority approval as a wall coating for slurry, liquid manure and silage effluent plants.

  • solvent-free
  • easiest handling because it is ready to use
  • universally applicable, therefore a multitude of possible uses
  • good adhesion and heat resistance
  • economical and cost-cutting, due to low equipment and material costs and effort
  • sprayable – fast and secure coating

BORNIT® Siloflex adheres to all substrates common in construction. The substrate must be dry, clean, grease-free and free from dust and separating agents. Fresh concrete must have thoroughly hardened for at least 28 days. The moisture content must not exceed 4 M% (measurement using CM equipment). Deposits, such as concrete slurry, must be removed using suitable measures. Build-up of aggregate, shrinkage cavities, cracks or ridges must be eliminated. The embedded aggregate particles at the surface must be exposed using suitable measures, such as, e.g., compressed-air jets with solid abrasives, high-pressure water jets or milling. Masonry surfaces must be smoothly and flushly jointed. Edges and fillets must be rounded off. The substrate should be dry. BORNIT® Siloflex must not be applied onto wet surfaces, since there, thorough drying is not given. Outgassing of concrete surfaces is a normal occurrence, which can result in so-called pinholes or bubbles, resp., in the coating. The risk of outgassing can be reduced by applying the material at dropping or constant surface temperatures. Therefore, it is an advantage to apply the first sealing layer in the afternoon. Until thorough drying, the coating must be protected from rain and strong solar irradiation. During the construction phase, no water must penetrate between substrate and coating. For better adhesion on mineral substrates, use BORNIT® Siloflex Primer or BORNIT® Siloflex diluted with water 1:1 (add water under stirring), resp., as a primer. In case of doubt concerning the substrate, test its compatibility with the material by applying it to a test surface.

BORNIT® Siloflex is spreadable and sprayable. Briefly stir up BORNIT® Siloflex prior to processing! For first-time coating or heavily strained surfaces, 3 coatings are required. With several coatings, each layer must dry thoroughly, the drying time depends on the weather conditions. The processing temperature (ambient and substrate temperatures) should not be below +5 °C and not above +30 °C. The surface temperature must be at least 3 Kelvin above the dew point temperature of the surrounding air. During application and until thorough drying, protect the coating from rain and direct solar irradiation. Filling of the silo must only be undertaken after complete and thorough hardening of BORNIT® Siloflex, after 7 days, at the earliest. For better processing of BORNIT® Siloflex, moisten the work equipment (roller, brush) with water beforehand. There must be no residues of solvents or diesel in the pumping equipment used. The pumps used should be large-volume pumps. The use of Pufas leaching agent has proven effective for cleaning and start-up.
In silage production management, it must be observed, in particular with grass silage, that the dry matter content per kilogramme of fresh matter is being complied with, the necessary degree of compaction is achieved, and the silage is correctly covered with vacuum film, gas-tight main film and silage protection grid in an air-tight manner immediately after termination of rerolling, in order to prevent reheating and butyric acid fermentation, which can result in damaging of the silo coating.

approx. 0.45 kg/m² per coat (3 coats required)

product data in brief
product type
polymer-modified bitumen coating
bitumen, additives
density at +20 °C
1.0 - 1.1 g/cm³
11.0 - 11.5
film-forming components
approx. 64 - 68 %
heat resistance
resistant up to +70 °C, according to AIB
fresh: brown/dried up: black
with roller, brush, sprayer, etc.
processing temperature (ambient and substrate)
min. +5 °C to +35 °C
when fresh with water, dried out with BORNIT® MultiClean Spray, BORNIT® MultiClean or BORNIT® Bitumen Cleaner
sensitive to frost!
shelf life
in originally sealed containers storable for 12 months
GISCODE link comp. A
substances hazardous to health in terms of the ordinance on hazardous materials
hazard class according to ADR
health and fire protection, occupational safety
For information on handling, safety and ecology, please refer to the current safety datasheet.

Can be stored for 12 months in original sealed containers. Protect from frost and direct solar irradiation!

disposal note
Only recycle completely empty containers. Only dispose of material residues according to AVV-ASN: 080410 (waste adhesives and sealing compounds except for those falling under 08409).

The above information replaces all 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 any changes in the information contained in this datasheet anytime.
BORNIT<sup class=® Siloflex, silo, coating, JGS, bitumen, solvent-free">
BORNIT<sup class=® Siloflex, silo, coating, JGS, bitumen, solvent-free">
recommended, personal protective equipment: