How to paint over render (and why!)

So you've decided to paint over existing render on your home's facade?

Refreshing the exterior of your rendered home can make sense both practically and visually, allowing upkeep of the home and staying on trend with popular colour schemes. It achieves two main goals: to protect walls from the damaging effects of the weather and to satisfy aesthetic needs.

However, the type of paint used for render is different than your average wall paint. Here we discuss the benefits of painting render, types of paint to consider and tips on how to apply it.

 

  1. Why should I paint my rendered home?

Protection

When applied, paint forms a protective film layer over render. This layer resists the UV component of sunlight, water penetration, fungus, lichens and microorganisms, surface erosion, freezing and premature aging. These are essential for the longevity of your home's facade and to keep it looking in tip top shape for years to come.

 

Adapting to changing trends

The use of colour is a major component in architectural design trends, and paint offers to opportunity to adapt and transform your home accordingly. Want your home to stand out from the crowd? Or perhaps to be one with its surrounds? A choice in colour will be an important step to achieving your vision.

If a change of colour isn't on the cards and the existing finish is simply looking a bit tired, a lick of paint can give it a nice refresh.

 

  1. Which paint should I use?

Paint for a rendered wall, otherwise known as top coat membrane, must be waterproof and vapour permeable. This is to seal the rendered surface and prevent moisture from entering while allow underlying materials to breathe. A quality paint will also boast good coverage and will conceal existing small cracks resulting from render shrinkage.

Some important characteristics of paint include:

  • resistance to the elements;

  • hydrophobicity;

  • degree of vapour permeability;

  • rheology and viscosity (ability to apply a paint layer evenly);

  • adhesiveness (adhesion strength of paint to the surface);

  • drying speed;

  • crack resistance or elasticity (ability to withstand expansion and shrinkage due to changes in external temperatures);

  • consumption (for rough surfaces the consumption will be higher);

  • safety (toxicity, for example, when using an organic solvent, fire hazard);

  • binder content (a low content, which can occur in low-cost compositions, reduces the service life);

  • durability.

At Render Supply Co, we stock quality top coat membranes manufactured here in Australia. A product we recommend using for your render painting project is the Unitex Uni-PTC. You can explore our range further here, or give us a call or visit.

 

  1. How do I paint over render?

Tools and supplies

Firstly, you want to ensure you have the right tools and supplies for the job.

You can choose to either apply paint by hand or use a paint spray gun. While we recommend painting render by hand, the latter can be a quicker way to paint large areas. Just be sure to appropriately prepare the area with masking tape and protective film (to protect windows), use ample drop sheets and cover all surrounds as you will get overspray! If painting by hand, invest in good quality rollers, poles/handles and brushes. You will also need a paint tray. Using thick paint on rough surfaces like render will require rollers with a higher nap (i.e., longer fibres). If applying a primer or sealer, foam rollers will be most ideal. Also consider having a couple of different roller handles at your disposal, as these come in various sizes which can greatly assist in your work. For example, shorter handles are suitable for easy to reach areas whilst long handles are incredibly useful for large and high walls, saving the need to access these difficult areas. Of course, you will need to appropriately cover and protect your surrounds when hand painting.

For both methods you will need a manual or electric mixer for preparing the paint before use. You'll also need a stepladder or scaffold for painting higher areas of the house, and protective equipment such as masks, goggles and gloves.

 

Preparation

Many people skip the preparation step and jump straight into the main event. However, a job done properly is a job done well, and skipping over preparation will likely be evident in the final finish. Key steps to take in preparation for the job will be:

  • Ensuring the surface to be painted is clean and dry;

  • Surrounding structures are protected with masking tape (e.g., window frames) and windows and other necessary structures are covered with protective film;

  • Surrounding ground areas are covered with drop sheets;

  • Furniture is removed from the area or covered with drop sheets; and

  • The paint is adequately stirred with a manual or electrical mixer (follow the instructions on the product label!). This is because the ingredients and pigment that make up the paint can separate, therefore mixing them together will ensure a consistent finish on the wall.

Further, it is essential to plan ahead and know what the weather will be before you start your painting project. Avoiding rainy weather, very hot days, or freezing temperatures will be necessary.

 

Application

Don’t apply the paint way too thick, rather work in multiple layers. Start from one end and work your way up and down, and across the wall quickly, ensuring to roll back the lines as you go. A rule of thumb is to always keep a “wet edge” to prevent the paint from drying and consequent lines showing through. You’ll also want to use a medium to firm touch – enough to apply adequate paint but not too much that lines begin to show over the wall. Further, try not to go over an area too many times while the paint is still wet or during drying. This will cause the paint to separate and stick to the roller, leaving behind an uneven texture. Finally, allow adequate time between coats, ensuring to following the manufacturer’s instructions.

 

After-care

Caring for your newly painted wall is essential for both longevity and aesthetics. Ensure it is regularly cleaned and free from dirt and grime to prevent bacterial and fungi growth.

Also, ensure to keep a record of the colour you used in case of any touch ups down the track!