Rendering a brick or block wall
Follow these simple step-by-step instructions to render a brick or block wall with Cement Australia Render It™ Multisurface.
Tools you will need:
- Metal trowel
- Wooden trowel
- Polystyrene float
- Plasterers hawk
- Steel brush
- Soft brush
- Tape measure
- Measuring jug
- Masking tape
- Access to clean water
Tip: If multiple batches of render are required to complete your job, it is worthwhile considering using a heavy duty drill and stirring attachment to make mixing easier and more consistent across batches.
Materials you will need:
- Bags of Render It™ Multisurface Grey or Off White
- Cement Australia Oxide
(if you are colouring your render)
- Black plastic sheeting
- Moulded corner beading
- Suitable adhesive
For an easy-to-use, one part render mix we recommend Cement Australia Render It™ Multisurface Grey or Off White.
Use on many surfaces, cure for 7 days before painting with water based paint
Select where light colour base is required
Before you get started
- Read the Hints & Tips section
- Plan to complete your rendering project in the early morning before the surface to be rendered is in full sun.
- Coverage: One 20kg bag of Render It™ will cover approximately 2.5 square metres at 5mm thickness.
- Use our simple Calculator to work out how much Render It™ product you will need for your project.
- Render It™ is suitable for both interior and exterior application.
Before you begin any project, please ensure you protect yourself with the following:
Look after yourself properly
- Protect your skin and eyes. Cement based products are alkaline and can cause burns to exposed skin or eyes.
- When working outdoors, be SunSmart - Slip on some sun-protective clothing – Slop on sunscreen - Slap on a hat - Seek shade - Slide on some sunglasses.
- All 20kg bags of cement products require 2 people to lift them safely. Always follow safe lifting procedures to avoid injury. You will need a friend to help you handle the 20kg bags and they can assist you in mixing the render and keeping the surface to be coated moist.
How to use Render It™ Multisurface one part render to cover a brick or block wall
Step 1: Preparing the surface
Remove any paint, laitance, plaster or any other loose material that may prevent good adhesion with a steel brush. Remove any brittle mortar in the joints of brick or block walls.
To protect the area from spilt render, cover paths or driveways with black plastic sheets and mask any other exposed surfaces you wish to keep clean.
Fix the corner beading to the external corners of the surface to be rendered using an approved adhesive ensuring it is straight and plumb to provide a neat rendered finish. You can use Render It™ Multisurface to attach the beading to the external corner if you don't have an approved adhesive available. Apply a small amount of render to the inside of the beading, press it firmly to the corner and clean off the excess render that is squeezed out.
Thoroughly wet the surface to be rendered with a hose on a light spray setting or using a wet brush.
Tip: If you are rendering a new brick or block wall ensure that the mortar has been cured for at least 7 days to prevent hairline cracks from appearing in your rendered surface as the mortar dries.
Step 2: Mixing the render
Only mix one bag of Render It™ Multisurface at a time.
Add 4 litres of clean water to a wheelbarrow and slowly pour one bag of render into the water. Mix thoroughly ensuring that the render is lump free and is stiff so that it will sit on a trowel. Allow the mix to stand for 5 minutes so that the polymer chemicals are activated and then quickly stir the mix again. Render It™ needs to be applied within 30 minutes of final mixing and any spilt render should be discarded.
Tip: A heavy duty drill mixer is recommended for large rendering jobs providing a more consistent mix, where manual mixing in a bucket or wheelbarrow is suitable for smaller projects.
Step 3: Applying the render
If you are rendering an existing brick or block wall, work the render into the mortar joints to provide a relatively flat surface, making it easier to apply a subsequent coat of render.
Start at the bottom of the surface to be rendered and apply the render with a steel trowel in an upward pushing motion. Ensure that you use long, even spreads upward and across the surface achieving a consistent and even thickness as you go. Fill any holes or divots with the render as you go. Do not overwork the surface as too much fine material will be brought to the surface increasing the likelihood of crazing (fine cracking).
Render It™ Multisurface can be applied in a thickness ranging from 2mm to 10mm in a single application. If subsequent coats of render are to be applied, the surface should be raked or scratched within 30 minutes of application to provide a rough surface for the next coat to adhere to. A minimum of 3 days must be left between coats to allow the render to develop maximum strength and prevent shrinkage cracks.
Step 4: Finishing the rendered surface
Allow the the final layer of render to become firm and finish off with a wooden trowel or polystyrene float to smooth and finish the surface to the desired texture.
To achieve a different texture a damp sponge can be used to provide a swirl or use a fine brush to provide a swept finish ensuring that not too much pressure is applied to the rendered surface.
Tip: If these techniques are not giving you the definition you want in your finish, wait until the render becomes firmer and finish the surface again.
Step 5: Curing the rendered surface
To prevent cracking, keep the rendered surface moist by spraying it with a mist spray 24 hours after the wall is finished and repeat this for 5 days.
Tip: Where the newly rendered surface is in full sun, it is vital to cover the surface to prevent rapid moisture loss. Failure to do so could result in cracking. If using plastic sheeting to cover the render, prevent the plastic from touching the surface as contact may lead the rendered surface to discolour unevenly.
Step 6: Painting the render
The rendered surfaced can be painted with water based paints after 14 days or after a minimum of 28 days where oil based paints are used.
Hints & tips
- To ensure a professional finish it is recommended to place moulded strips (called beads) on the corners of the surface to be rendered. These strips are available from any leading hardware store.
- In warm conditions when the render begins to stiffen, it is suggested to mist spray the applied render to maintain its finishability.
- Render It™ Multisurface should not bridge the damp course and rendering below the level of the damp course is not recommended. Weep holes should carry through the render.
- If you have expansion joints in your surface, cut matching joints through the render after finishing the surface to prevent cracking at these joints.
- Rendering a large surface requires a high level of skill and we recommend that you call in the professionals if you are not an experienced renderer.