Rudomal Duct Cement is an alternative to installation of flexible liners, when one wants to retain the whole of the existing area. Easy to use and ready to dilute with water.

Area of use
Internal sealing of masonry flues for hearths and existing masonry ventilation with self-induced draft and extration ducts for kitchens.

Rudomal is an easily worked mortar with good adhesion and consistency. For hardening to occur more slowly a delaying additive can be added if necessary.

Temperature range
For hearths with heat outputs of a maximum 120kW. Not recommended for use at air temperatures below +5°C.

Granule size
Granule size 0-1 mm

Type approval certificate: 0642

Westafix, Winch and draw pad.

Hack out a work hole in the bottom of the defective flue.
Clear/clean the flue with a sweep’s brush or rotating tool to create a brick contact surface.

Place the winch on the chimney top above the defective flue. Lower the wire down the flue. Install draw cloth, foam rubber cone and brush on the wire. Tension the wire so that the draw tool is just above the work hole. Cover the work hole with a foam rubber pad.

Mix a priming mortar (wet mortar) approx. 6-7 litres of water to 25 kg dry mortar. Mix well for approx. 3-4 minutes so that the air is mixed into the mortar. Let the mixture rest for 2-3 minutes and mix again.

Pour in the mortar from the top of the chimney so that the draw tool is thoroughly covered in mortar. Start to winch up the draw tool at an even speed. The draw tool must always be covered with mortar. For the best results fill the mortar continually from above without stopping the process.

When the priming is complete, draw the flue through once more in the same way (final draw). When drawing the final time the mortar can be a drier mix with 5-6 litres of water to 25 kg dry mortar. The procedure can be repeated if the flue needs to be drawn again with more mortar.

Close the work hole.

Contact an authorised inspector to approve the flue.

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