Roundtower Wintermix

Roundtower Wintermix is a blend of Natural Hydraulic Lime and secret specially selected herbs and spices. This carefully formulated render rapidly develops enough strength to resist damage from any ice crystals forming in the render, while other work aids limit the size of any ice crystals that do form.

Binder Strength – NHL 3.5

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Usage:‍

Factory blended mortar using a coarse kiln dried sand and NHL, combined with carefully selected additives to improve the mortar’s physical and mechanical properties, whilst maintaining all of the virtues of a pure Natural Hydraulic Lime mortar.

The strength gain is designed to take place within the first 10 days of curing, once it has reached this point Wintermix performs and behaves in the same manner as a standard NHL3.5 render.

Roundtower Wintermix is designed specifically for use during colder months were an increased set and strength gain is required.

With carefully selected additions Wintermix is able to reach a strength that is resistant to frost damage within 4 to 5 days.

Predominately used as a base coat for render, Wintermix can also be used as a bedding mortar for building works.

Suitable for applications in building conservation where the binder strength is appropriate for the host background/surface.

Please note that whilst NHL 3.5 is the binder strength used, the strength of the mortar is closer to an NHL 5

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Colours:

Wintermix 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.

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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.

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

Mixing:

A 25kg bag of Wintermix 1:3 will require 4 to 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 Wintermix and turn the mixer on. Allow the mortar to mix until the water is thoroughly distributed, then add additional water to achieve desired consistency.

Mixing time - Mix for a minimum of 5 minutes, but for no longer than 10 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.

Quenching - Like most lime mortars Wintermix will benefit from Quenching; allow the mortar to stand for 10 to 20 minutes after mixing, before use. Should additional water be needed after quenching to maintain workability, this can be added and mixed thoroughly through the mortar.

Once water has been added, Wintermix 1:3 has an open time of at least 8 hours. Longer in colder weather

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