Hempcrete Australia stipulates the use of breathable Lime and Clay renders for healthy and natural wall finishes. This leads to an all natural home - hemp as an aggregate in the walls, lime as binder, and clay and lime as a finish. This breathability is what allows the hempcrete home to regulate humidity and temperature - providing not only a healthy, but also an extremely comfortable home.
Exterior Render
The last coat on the exterior of the building must be a Lime Render, which has water repellant properties.
Internal Render
Hempcrete can be coated with any of the lime or clay renders including lime washes (see list below). You may also leave the hempcrete wall surface un-rendered or coated with a clear breathable finish.
HEMPCRETE AUSTRALIA SUPPLIES THE FOLLOWING RENDERS:
ROCKCOTE (Australian) has a range of Earthen Renders and Lime Renders which are made from pure ingredients and are free from synthetic additives and toxins.
ST ASTIER (Imported) manufactures EcoMortar Premixed natural hydraulic lime building mortars.
Please see below for a summary of the breathable renders:
1. ROCKCOTE CLAY PLASTERS
1.1 Rockcote Clay Plaster Decor - Technical Date Sheet here
ROCKCOTE Clay Plaster Decor is composed of high quality natural earth materials manufactured to exacting specifications, composed of high quality washed and graded Sands, various Clays and proprietary additives. ROCKCOTE Clay Plaster Decor is designed as a decorative finishing Render that can be tinted to a range of earth tones using natural oxides. Dry, clean, hemp, chopped wheat straw, rice husks, quartz chips, marble chips and shells can be added to create beautiful and unique effects.
1.2 Clayset - Technical Date Sheet here
ROCKCOTE Clayset is a traditional clay plaster comprised of pure mineral components and a natural gypsum setting agent. Supplied as a dry blended powder containing no VOCs or harmful chemicals, Clayset requires only the addition of clean water prior to application. Clayset is an extremely versatile product that allows the skilled artisan the potential to achieve a wide range of stunning decorative effects as well as the option of a textured or polished and smooth finish for internal walls and ceilings. Clayset can be tinted to a wide variety of colours, however it is neither possible nor desirable to achieve an exact colour match due to the uniqueness and variations in a natural mineral product. Clayset is fully recyclable and easily incorporated back into the environment.
*Please note: Bathrooms in a hempcrete house have specific design requirements.
1.3 Earthen Render Coarse - Technical Date Sheet here
ROCKCOTE Earthen Render Coarse is composed of high quality natural earth materials, washed and graded sands, various clays and proprietary additives. It is designed to be used as a base coat render which can be overcoated with finish coats of ROCKCOTE clay products if desired. ROCKCOTE Earthen Render Coarse is a versatile product that is suitable for application over properly prepared substrates ranging from plasterboard to straw bale and hempcrete.
1.4 Earthen Render Medium - Technical Date Sheet here
ROCKCOTE Earthen Render Medium is a completely natural product composed of high quality natural earth materials, washed and graded sands, various clays and proprietary additives. ROCKCOTE Earthen Render Medium is designed to be sponge finished and painted, or left in its natural state. It is also suitable to be overcoated with other ROCKCOTE Clay products or alternatively, can be tinted to a range of Earth tones with the use of oxides. ROCKCOTE Earthen Render Medium is a versatile product that is suitable for application over properly prepared substrates ranging from plasterboard to straw bale and hempcrete, as well as previously painted surfaces.
2. ROCKCOTE LIME BASED
2.1 Lime Wash - Technical Date Sheet here
ROCKCOTE Lime Wash is based on a traditional coating with just enough modern ingredients to perform in the modern world. ROCKCOTE Lime wash provides a breathable decorative finish that penetrates into the underlying substrate to which it is applied. ROCKCOTE Lime Wash is primarily composed of slaked lime (calcium hydroxide) and a low proportion of binder to ensure that it performs in the modern world. The calcium hydroxide sets by slowly combining with carbondioxide to form calcium carbonate.
2.2 Lime Plaster Basecoat - Technical Date Sheet here
ROCKCOTE Lime Plaster Basecoat is a fine grained lime plaster that can be used both interior and exterior including areas of high humidity*. It is composed of hydrated lime, natural aggregates and additives.
3. ROCKCOTE NATURAL CLAY PAINT
3.1 Clay Paint - Technical Date Sheet here
ROCKCOTE Clay Paint is a premium quality, Flat Clay finish that is user friendly and environmentally friendly. This zero V.O.C. (Volatile Organic Compound) paint is ideal for users who are health conscious and concerned about environmental air pollution and indoor air quality. Areas painted with ROCKCOTE Clay Paint have no lingering Paint fumes and no off-gassing of VOCs. ROCKCOTE Clay Paint is made from high grade components, including Australian sourced refined kaolin clay. ROCKCOTE Clay Paint provides excellent opacity and will not support the growth of mould, mildew or fungi.
4. ST ASTIER NATURAL HYDRAULIC LIMES (imported)
4.1 EcoMortar Premixed natural hydraulic lime building mortars - Technical Date Sheet here
St Astier Natural Hydraulic Limes (NHL) Premixed natural hydraulic lime mortars for building, rendering and finishing coats in a variety of colours.
The absence of cement, ashes and other pozzolanic additions together with its other qualities, make EcoMortar highly suitable for repair and conservation work on traditional, vernacular and historic buildings. In new build the properties of EcoMortar will allow joint free construction, dispersion of condensation and will accommodate small settlement movements.
Ecofriendly characteristics:
- High vapour exchange qualities
- Produced with lower energy than cementitious mixes
- Re-absorption of CO2 in curing
- Will not deteriorate timber
- Possibility of recycling the materials used in building
- Elimination of painted finishes