Master Painters Australia

How to Prepare Exterior Surfaces for Painting

Do you want brilliant paint on your home or building’s exteriors that will stay vivid for months and years?

Before grabbing those painting tools, take some time to prepare the surface. Surface prepping is critical for treating metal and other substrates before being painted, coated or lined. Chemical or mechanical surface preparation clears the surface of pre-existing coatings, residue, imperfections, organic matter, oxidation and other contaminants. While there are different ways to prep the surface of different materials, they all tend to follow similar processes.

Complete surface preparation involves cleaning, repairing, sanding, patching, masking and priming. These processes may seem tedious and take a lot of time, but they are a critical step. It is estimated that 80% of paint failures result from improper preparation of the surface.

Painting Exterior Surfaces: 7 Steps

You can uplift your home’s curb appeal with a fresh coat of paint. The following discusses how to prime the outside of your home, application techniques and painting solutions.

Step 1

Both home painting contractors and commercial building painting contractors know that cleaning the surface is a core step for a good painting job. A pressure washer combined with the proper detergent is the most effective way to clean exteriors thoroughly. 

However, extreme caution must be practised when choosing the pressure washer’s nozzle. A strong and concentrated stream of water can damage wood, seep under sidings and break windows. A standard garden hose and scrub brush will do the job for surfaces with no excessive peeling or flaking.

For preventing mildew:

  • Use a detergent with mildewcide or a combination of household bleach and water.
  • Follow the manufacturer’s instructions for any cleaning product you use.
  • Rinse the surface thoroughly after cleaning.

Step 2

Using a wire brush or scraping tool, remove loose paint or flaking in areas the pressure washer cannot reach. If the old paint is intact, scraping to the bare wood isn’t necessary. These areas can be painted over after sanding.

Step 3

When there are surface flaws, painting contractors in Sydney first repair them by utilising surface repair products rated for outdoor use. The area should then be dried, and the surface is sanded after.

Step 4

Worn and old caulk should be removed. So, apply caulk to critical areas, such as door trim, windowsills and other parts that need to be sealed.

Step 5

Repair and apply putty on windows. Scrape off the old putty and paint with new glazing. Completely dry the area before painting.

Step 6

With a drop cloth, protect nearby bushes, flowerbeds and footpaths. Tie and cover shrubs to prevent them from rubbing against the fresh paint.

Step 7

Prime bare wood and other areas once repairs have been made.

How to Prepare Surfaces for a Paint Job

Not all surfaces are the same. This section explains how to prep each surface type for a successful paint job.


Although metal surfaces can be coated, the challenge with coating metal is that rust forms almost immediately once the surface is prepped. To make sure the paint adheres to the metal, use a drill with a wire wheel brush and scratch the metal surface aggressively. Afterwards, apply a coat of primer.

Wood [H3]

Wood is porous and flexible. These features present a challenge when coating. Wood must be sanded to clean the surface and establish a bond profile for the next layer. After firmly attaching and sanding the wood, it can be primed and coated.


Similar to wood, drywall is highly porous. Moreover, it has a paper covering called gypsum. These elements severely mitigate coverage rates.

To properly prep drywalls, check the surface for nicks and gouges. Fill these gaps with drywall mud or make your own with three parts soda and one-part white glue.

Afterwards, run a pole sander using light pressure—sand the area in circular motions to avoid scratching the drywall.

Vacuum and remove dust by running a dark-coloured rag over the drywall. If you see specks of white dust on the rag, vacuum the drywall again. Wash the wall using a vinegar solution and dry thoroughly.

Ceramic and Quarry Tile

For vertical tiles, clean the surface and sand it with a grit palm sander, ideally, a 16 grit. Using a microfiber cloth, wipe the tiles and make sure small particles that fell away during the sanding process are completely removed.

For quarry tiles often found in commercial kitchens, the best prepping method is to diamond grind or shot blast the surface. The most critical step is cleaning the grout lines. Once done, clean the surface with hot water and a degreaser.


Painting contractors in Sydney know that concrete material poses a unique challenge because 99% of all concrete projects have a thin film curing agent applied on the surface. This curing agent helps the concrete dry without cracking, but it conflicts with epoxy coatings.

Therefore, it is crucial to remove this thin layer of silicon-based compound. Aggressively sand, diamond grind or shot blast the surface. The goal is to create a surface with the smoothness of 36 grit sandpaper, otherwise called Concrete Surface Profile (CSP 3).

Once you have completed this process, the long-term adherence of coatings and systems will be increased by ten times.

Exterior surfaces are exposed and constantly blasted by harsh weather elements. For this reason, you need to prep surfaces carefully so as not to waste your efforts and materials.

Many homeowners and building owners hire a contractor to prepare and paint their exteriors. Painting contractors in Sydney know well that surface preparation involves various methods to treat the surface of the material before applying the coating, adhesives and other procedures. 

To find the right person for the job and get high-quality results, consider asking for recommendations. Excellent reference sources are friends and family. Once you’ve got a list of the potential home painting contractors or commercial building contractors, check their credentials. You must also verify whether they have appropriate licenses.

In Australia, commercial building painting contractors and decorators commissioned for domestic and strata projects must be backed by a license from the NSW Office of Fair Trading. So, you should see proof of their license and a Certificate of Currency for their workers’ compensation and public liability insurances. Bear in mind that for projects that cost $20,000 and above, they must present a Home Warranty Insurance Certificate.

Finding a Master Painter in Australia

If you’re looking for a colour consultant or a master painter, we can help you.

Master Painters Australia is a not for profit industry association representing painting and decorating contractors and employers in NSW. Our members are backed by proper licenses to ensure quality work and warranties. Call us on (02) 9758 8877 for more details.