Claytec Undercoat Plaster

clay and straw undercoat plaster
‘Clay undercoat plaster is a blend of clay, fine aggregate and plant fibres that is supplied as a dry powder. It has an indefinite shelf life if stored dry and requires only mixing with clean water to be ready for use. It hardens by drying - no chemical reaction takes place - and so remains workable for a long time and can be re-worked by the addition of water at any time.

Clay undercoat plaster is suitable for use on internal surfaces of walls and ceilings. It attaches by mechanical bonding to all stable and dry substrates, including masonry, clayboard, reedboard, timber lathing and lime undercoat plasters. Undercoat plasters are not recommended for use on plasterboards because during drying, water will be absorbed by the board which will then become unstable.

The versatility, flexibility, ease of application and cost-effectiveness of clay plasters makes them a practical alternative to gypsum based plasters. Clay plaster has excellent properties of regulating both temperature and humidity, making it ideal for ‘breathing’ constructions. Clay plaster also has the major advantage that it can be reworked at any time in the future.

• Clay plaster can take picture hooks, wallpaper and paints
• Clay surfaces are cool in summer and warm in winter
• Clay surfaces absorb and diffuse water vapour
• Clay absorbs odours
• Ideally suited for high comfort, modern buildings and historic building refurbishment
• Clay plaster can be reworked at any time
• Clay plasters are 100% natural’
  • Claytec Undercoat Plaster (image 1)
  • Claytec Undercoat Plaster (image 2)
  • Claytec Undercoat Plaster (image 3)
  • Claytec Undercoat Plaster (image 4)
  • Claytec Undercoat Plaster (image 5)

Environmental metrics

Company credentials

clay, washed sand and barley straw

Life expectancy

EPD to ISO 14025

Recycled content


3rd party product endorsement

Environmental labelling

Country of manufacture

Manufacture details


Nettetaler Strasse 113, 41751 Viersen-Boisheim, Germany

0049 (0) 2153/918-0


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