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Auro 396 Natural Cavity Filler

Currently out of stock

Prices Include VAT

Currently out of stock

Prices Include VAT

Auro 396 Cork Filler is an ecologically sound decorator's caulk and window and door gap filler. An environmentally friendly alternative to using construction foam. It fills cavities between brickwork and window and door frames providing excellent sound and heat insulation.

This natural, solvent free, breathable filler for gaps around window and door frames is the ideal choice for a truly environmentally conscious home. It can also be used between butted joints for example wooden boards, sheet metal, stone and masonry work where through gaps are closed off on one side.

It can be used inside and outside and can be overpainted. Once dry, the cork filler remains open-pored (breathable).

The solvent-free cork granulate with an elastic organic binding agent can be applied with the Auro Caulking Gun.


  • Manufactured from natural minerals and materials. Auro Raw Material Guide (opens in new tab)
  • Suitable for sealing gaps around windows and doors and the surrounding stone/brickwork, inside and out*.
  • Also suitable for butted joints between wood, sheet metal, stone and masonry work.
  • Very low VOC Level: 0 g/l
  • Solvent Free
  • Flexible
  • Easy to use (ideally with pressurised caulking gun - see options)
  • Breathable
  • Colour: Cork coloured
  • Vegan


  • Water
  • Natural latex
  • Cork
  • Xanthane
  • Rosemary oil
  • Thiazole

Drying time: Approx 1mm thickness per day.

Further Information:

*Please note: It is not weather resistant without an additional coating - see technical datasheet. Not suitable for application over lime - please consider Burnt Sand Mastic instead.

Natural products are neither odourless nor emission-free. The use of organic, natural and plant based ingredients means that allergy and asthma sufferers and people who are chemically sensitive are much more able to tolerate Auro products, however they may cause allergic reactions in some. If you wish to know about what raw ingredients Auro use in their products please visit our Auro Raw Materials Guide.

For more detailed information, download the 396 Technical Data Sheet and Safety Data Sheet (opens in new tab).


See the 396 Technical Data Sheet for full details, however in brief:

  • Remove any loose material.
  • Crumbling surfaces can be consolidated with Auro 301 Natural Plaster Primer.
  • Cut off the clip and equip the caulking gun with the plastic tube.
  • Screw on the closing cap with the nozzle, cut at an angle.
  • Fill the joints evenly with the cork filler.
  • Smooth the surface with a spatula.
  • Paint as required, carry out preliminary trials if necessary.

Cleaning tools

Optional Extras

Auro 06700 Caulking (Pressure) Gun

Ideal for squeezing out and applying Auro Cork filler No. 396, the ecological alternative to conventional sealing materials.

Comes with 1 x Caulking Gun Nozzle (Auro 06701)

Please note: The lead time for the caulking gun is 2-3 weeks.

Take a look at our Guide to fillers to see which product is best for your project.