Plaster is the coating of a surface with cement render or plaster finish on an internal or external wall. Plaster is for decoration and protection of every building.
The role of external plaster is not only to primarily protect the covering structures of the building against the impacts of the external environment (rain, wind, sunshine), but also to provide thermal and sound protection of interior areas.
Please see below our step-by-step guide to rendering; alternatively you can download our printable copy here:
Clean the surface you intend to render, removing any dirt, dust, oil, grease or paint.
Smooth or polished surfaces may require a bonding agent (primer). This should be available from most hardware stores. If you are unsure, seek professional advice.
Highly absorbent surfaces such as sandstone or porous blocks should be well dampened immediately prior to rendering.
If required, nail the wooden battens at each end of the wall to act as a thickness guide for your render, and to give you a clear edge to work to.
Using the following table, calculate how much DryPak® Render Coat™ you will need for your project.
Mixing the render
Do not mix more render than you can use within one hour.
Pour three litres of water into a clean container such as a 20 litre bucket, for each 20 kg bag of DryPak® Render Coat™ used.
Using a suitable mixing device, agitate the water while steadily adding the DryPak® Render Coat™ powder.
Once all DryPak® Render Coat™ has been added, mix thoroughly until an even consistency and colour is obtained.
Do not add too much water in the following step as this will cause shrinkage, cracking and low strengths. No more than four litres of water should be used for each 20 kg bag of DryPak® Render Coat™.
If necessary, add a small quantity of clean water (maximum of one litre) while mixing to achieve the desired consistency.
Spillage or partially set material should not be re-tempered with water, and must be discarded.
Clean your tools and equipment as soon as possible to prevent further applications from being contaminated with old material.
Applying the render
Apply a heaped amount of DryPak® Render Coat™ to the steel float.
Righthanders should begin from the left of the work area, lefthanders should begin from the right.
Starting at the bottom of the work area, move the float upwards along the wall in an arc, scraping the material onto the surface at the desired thickness (wooden battens nailed to the edges of the work area are good for gauging the thickness of the coat).
Continue applying the DryPak® Render Coat™ to your wall using this technique until the area is covered to the required thickness.
Remove wooden battens if used, and apply DryPak® Render Coat™ to the edges.
Once the surface is completely covered, rub the float over the wall in a wide circular motion to ensure an even coverage. If you notice that the float is ‘pulling’ at the surface of the render, it may not be ready to be floated. Wait for 10 minutes and try again.
If you are applying a second coat, wait at least 24 hours between coats.
Finishing the Render
There are a wide variety of finishes that can be achieved. Rub different types of floats and materials over the surface to achieve the desired finish. Try the following floats and materials:
- Smooth Finish – Float the surface with a steel trowel
- Standard Finish – Use a foam float for a traditional finish
- Bagged Finish – Use a ball of wet hessian
- Brushed Finish – Drag a stiff brush over the surface
- Sponge Finish – Mop the surface with a damp sponge
- Painted Finish – Use an oil or alkali based paint
DryPak® Render Coat™ should not be allowed to dry our for at least three days to ensure proper strength is achieved.
DryPak® Render Coat™ must be protected from the hot weather direct sunlight, drying winds and rain.