Ty-Mawr Lime Hemp Plaster

made from a natural, renewable fibre (instead of depleting a natural aggregate resource).

has thermal and acoustic properties.

can assist with the airtightness of old buildings.

can be a successful way of ‘patching’ old lime plasters e.g. where electricians have been ‘chasing out’.

is easier to use than conventional lime plaster (minimal shrinkage).

is more resilient for use on corners etc.

no requirement to use mesh or add hair.

can be applied in much thicker coats than traditional lime plaster therefore is especially useful for ‘dubbing out’ walls prior to further plaster coats.

What is Ty-Mawr Lime hemp plaster made from?

Ty – Mawr hemp lime plasters and renders are made from the chopped stem of the industrial hemp plant blended with high calcium lime (also known as a fat / putty or non-hydraulic lime). It is made entirely from British materials.

What are the benefits of using lime/hemp over a standard lime plaster?

•Ty-Mawr hemp lime Plasters and Renders require exposure to Carbon Dioxide in the presence of moisture to harden. Hemp/Lime is faster setting and can be applied in thicker coats than conventional lime plasters.

 •It is more environmentally friendly- Hemp is a renewable resource which as a plant locks in CO2 as it grows. Using hemp instead of sand also avoids the removal of natural resources from the ground.

What is lime hemp plaster suitable for?

Like all lime products, it is flexible and breathable which makes it suitable for use in the restoration of old 'solid wall' construction buildings as well as ecological new builds, it also provides additional insulation.

Lime hemp plaster is suitable for backing coats, textured finish coats and for external rendering. Your finished plaster will care for your building for years to come as well as helping to control the humidity of the internal environment.  

How much will I need?

• 25kg bag covers approx 0.75m2 at 25mm coat.

• 1 tonne covers approx 30m2 at 25mm coat.

Is lime hemp plaster applied in a similar way to regular plaster?

Hemp Lime plaster is easier to apply than conventional plaster because of its fibrous properties and minimal Shrinkage  

Detailed sheets and specialist tools are available from us for the application of this plaster.

How should the surface be prepared?

• Pre-wet the background - the stone/bricks/laths must be wetted to saturation by spraying (usually 2 or 3 times) before application. Lime plasters or renders will carbonate whilst moist, if they dry out before they carbonate, they will fail and turn to dust.

• Each coat must also be dampened down before applying the next coat.

How is the plaster applied?

• Unlike normal lime plasters, lime hemp plasters can be applied in single coats 10-50mm thick.

• Wet the surface before working it over with trowels or floats, by splashing with water. Over-wetting should be avoided.

How long does it take to dry?

It can take anything between 1 week to a month or more to completely dry depending upon the substrate, thickness of application, wetness of material and weather conditions.

• Do not use dehumidifiers and heaters to speed up the set. Accelerated drying will prevent carbonation and may cause the plaster/render to fail. Gentle heat may be used cautiously in cold, damp buildings.

• Protect new work with damp hessian; plastic sheeting may also be required to prevent rapid drying in hot weather, when windy or in direct sunlight. Gentle spraying may be necessary if areas of plaster or render are drying too quickly.

What protective precautions should be taken whilst drying?

• Protect new lime plaster or render from frost - external work, wherever possible should not be carried out when temperatures are likely to fall below 5°C before carbonation has taken place. If work must continue externally, although not advisable, the scaffold should be fully enclosed and well-circulated heating supplied. Internally, it may be appropriate to supply gentle heating.

• Protect from rain - heavy rain can wash the lime out, or at least, draw it to the surface before the render has carbonated. A new render should be protected until surface carbonation has taken place.

How should the plaster be stored?

• Store airtight and frost-free

• Premixed lime hemp plaster will become hard over time and require more ‘knocking-up’.

• Use within three months of purchase.

How can it be finished?

Lime hemp plaster gives a beautiful finish that no modern plaster can replicate. We highly recommend that you finish it with a ‘breathable’ and preferably a natural paint. Your choice will depend on the level of durability, required vapour control and desired aesthetic.

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