glaster Premixed Scratch/Base Coat Plaster - Wet

will help to control condensation and damp, thus creating a healthier building by controlling relative humidity
enable other sustainable building materials to be used such as wood, straw, woodfibre boards, clay and earth

can be recycled at the end of its useful life and will allow other building components to be reclaimed

technically excellent with some performance advantages over sand based equivalents

is versatile – it can be hand or spray applied to stone, brick, laths or wood wool boards

produces a unique aesthetic by combining different colours of glass with pigments

reduces the demand for sand (currently 2 million tonnes per annum are extracted depleting a natural resource). For every tonne of recycled glass used, 1.2 tonnes of raw materials are preserved.

reduces the amount of glass going to landfill. Although glass is not directly hazardous to the environment, it will remain there indefinitely, so it helps to develop a market for the 8% of household waste.

this product is made in our manufacturing yard that operates under our iso9001:2008 quality management system and the Green Dragon Level 2 environment standard.

“30 gallons of oil are saved for every tonne of glass which is recycled. “ Friends of the Earth

What is Glaster plaster suitable for?

Glastercan be used as a mortar for building or as aplaster/render for internal and external walls. It can be manually applied or spray applied, and can be trowelled to a polished finish if required or sponged to reveal more of the aggregate. It can be applied to most conventional substrates such as stone, brick, block and building boards. They can be used as a decorative finish for internal plasters and external renders, or as building mortars. They have undergone testing against European Standards (please call for further information).


What are the environmental benefits of Glaster?

The award-winning Glaster products are beneficial to the environment because they reduce the extraction of sand whilst developing a market for recycled bottles.


What sort of finish does Glaster give?

Glaster can be varied by adjusting the colour and size of the glass aggregate, to provide, for example, a fine all-blue finish or a coarse mixed green finish. Natural pigments can also be added to the lime plaster to vary the background tones. Alternatively, it can be painted like an ordinary lime plaster with any of Ty-Mawr’s vapour permeable paints.


How should the surface be prepared?

Thoroughly wet all stones/bricks and adjoining surfaces by spraying with water or immersing in water, otherwise they will ‘suck’ the moisture out of the mortar before it sets, causing it to fail and turn to dust.

Large holes should be packed with lumps of stone or bricks, as large volumes of mortar will shrink. (Please consult Ty-Mawr Building or Pointing Technical sheets for further information.)


Approximately how much Glaster will I need?

Base/Scratch Coats
1 x 25kg bag covers 1sqm @ 7-8mm thick
1 tonne covers 40sqm @ 7 – 8mm thick

Finish Coats
1 x 25kg bag covers 3sqm @ 3mm thick
1 tonne covers 120sqm @ 3 mm thick



What protective precautions should be taken whilst drying?

• Protect new work with dampened hessian first with plastic sheeting on the outside to prevent rapid drying in warm weather, particularly when windy or in direct sunlight. Gently spraying the render and hessian sheeting with water will help to slow the drying process.
• Do not use dehumidifiers and heaters to speed up the drying process. Accelerated drying will prevent carbonation (which takes place in the presence of air and moisture) and may cause the plaster / render to fail.
• Protect new work from frost. External work, wherever possible should not be carried out in temperatures of 5°C and falling. Internally, it may be appropriate to heat the room gently using a convection or gas on a ‘LOW’ setting. In winter, externally, the scaffold should be fully enclosed and well-circulated heating supplied.
• Protect new render from rain. Rain can wash the lime out, or at least draw it to the surface before carbonation has taken place. A new render should be protected until surface carbonation has taken place.


How should it be stored?

The premixed products cannot be stored and kept in the same way as their component parts.
They should be used within ONE month. Pre-mixed glaster (putty) given time will become solid in the bag and take more effort to chop up with a shovel and ‘knock up’ in the mixer, in which case a mortar mill can be more favourable.
Note: Premixed Dry glaster (Hydraulic Lime) should be stored indoors in a dry place.

This section is under development, please email tymawr@lime.org.uk for systems builds and NBS clauses.