Roundtower Tanking Render

Factory blended mortar using a coarse kiln dried sand and Prompt Natural Cement, combined with carefully selected additives to improve the mortar’s physical and mechanical properties, whilst maintaining a waterproof and sulphate resistant coating.

For the majority of applications, we strongly advise against the use of tanking treatment on solid walls as the masonry should be allowed to breath, however in certain applications and locations, Tanking Render can be suitable.

Usage:

Tanking Render is designed for application where the presence of liquid water is constant, examples of this can be application underground such as basements or coastal applications where salts are present and have degraded the fabric.

Conventional tanking treatments usually rely on chemical based slurries, which firstly require a cementitious mortar to be applied, followed by numerous applications of a tanking slurry/treatment. Roundtower Tanking Render can be applied directly to the host surface as two 10mm coats, acting as both a render coating and a taking treatment.

Suitable for applications where the masonry is subject to constant/regular presence of liquid water and/or salt damage. Please contact the manufacturer for further technical information.

Setting Time:

The setting time of Tanking Render will be temperature dependant.

In warmer/summer conditions the setting time will be approximately 30-40 minutes.

In colder/winter conditions the setting time will be approximately 75-90 minutes.

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Colours:

Tanking Render is entirely natural in colour. No pigments or colourants are added.

For applications where colour is important (pointing, unpainted render finish), we strongly advise that sufficient quantities of mortar are purchased and all bags from the same batch to ensure consistency.

Preparation:

In general, this will be determined by the purpose and application of the mortar.

We would expect appropriate preparation in accordance with best practice; where the surface is clean, free of dust and other debris. Where necessary the background should be adequately dampened to promote adhesion/bond with the host surface. Dense impervious backgrounds/materials are unlikely to be very absorbent and require little to no dampening, whereas more absorbent backgrounds/materials require adequate dampening in order to prevent rapid drying.

When applying two coats, this should be carried out on the same day with two hours between coats.

We advise a base coat of 10mm that can be scratched, followed by a further 10mm coat. We would then advise a lime plaster is applied over the Tanking Render. As tanking solutions can be prone to sweating, a lime plaster will enable this excess moisture to be released.

Whilst Tanking Render includes additions to try and mitigate these issues, best practice still needs to be followed.

Mixing:

A 25kg bag of Tanking Render will require 4.5 to 5.5 litres of clean potable water. The water addition will vary according to the application and desired consistency/workability of the mortar. Always avoid making the mortar too wet, as this can promote shrinkage issues, especially when used as a render.

For drum type mixers, it is essential not to overfill the mixer.

As a dry mixed material, it is possible that some settlement or separation may occur in the bag during transit; when mixing part bags, it is especially important that the dry contents are thoroughly blended prior to mixing with water.

Best Practice/Advised Mixing - First add 60 to 70% water of the total water into the mixer, followed by the Tanking Render and turn the mixer on. Allow the mortar to mix until the water is thoroughly distributed, then add additional water to achieve desired consistency.

Mix for a maximum of 5 minutes.

Other mix methods - We accept that it is generally site practice to add the water to the mortar, providing the mortar is well mixed and not too wet, this method will be sufficient. Whisk mixers are also an appropriate mix method.

As Tanking Render is a fast setting mortar we recommend its use immediately after mixing.

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