Exterior painting looks straightforward from the outside:
prepare the walls,
apply the paint
and deliver a clean, professional finish.
In reality, a successful exterior painting project starts long before the first roller or spray gun touches the wall.
Weather exposure, surface condition, moisture, previous coatings, substrate type, preparation requirements and product selection can all affect the final result. If these factors aren't assessed properly, contractors can face peeling paint, cracking, uneven coverage, callbacks, additional labour and unexpected costs.
For contractors, the most important question isn't simply
"What paint are we using?"
It's:
"Is the surface and project ready for the coating system we're planning to apply?"
Here are the key things contractors should check before painting exterior walls.
1. Inspect the Condition of the Existing Surface
Before choosing a coating, inspect the wall carefully.
Look for:
Cracks
Flaking or peeling paint
Powdery or chalking surfaces
Blistering
Damp areas
Staining
Algae or mould
Efflorescence
Loose or damaged plaster
Uneven or previously repaired areas
Don't assume that because a wall looks acceptable from a distance, it is ready for painting.A closer inspection can reveal problems that will affect adhesion and the appearance of the finished coating.
Why this matters
Painting over a failing substrate doesn't solve the underlying problem.If loose material remains beneath the new coating, the new paint may eventually fail along with the old surface.
For larger projects, identifying these problems before work begins gives you an opportunity to plan the required preparation and discuss additional work with the client before it becomes a problem.
2. Check for Moisture
Moisture is one of the most important factors to investigate before exterior painting.
Look for:
Damp patches
Water stains
Leaking gutters
Downpipes discharging against walls
Roof leaks
Cracks allowing water penetration
Poor drainage
Rising damp
Areas exposed to persistent moisture
If moisture is entering or becoming trapped within the wall system, applying a new coating may not address the underlying problem.
Ask yourself:
Where is the moisture coming from?
Has the source been corrected?
Is the surface sufficiently dry for the planned coating system?
A beautiful paint finish won't remain beautiful if water is continually entering the substrate.
3. Identify the Substrate
Not all exterior walls are the same.
You may be working with:
Cement plaster
Concrete
Brick
Previously painted masonry
Fibre cement
Other specialist substrates
The substrate can influence preparation, priming and product selection.
Before ordering materials, establish exactly what you are painting and whether there are different substrates on the same project.
A new plastered section may require a different preparation approach from an older previously painted wall.
Don't treat every wall the same.The coating system should be appropriate for the substrate and the conditions in which it will be exposed.
4. Test Existing Paint and Coatings
If the building has already been painted, investigate the existing coating.
Check for:
Peeling
Poor adhesion
Chalking
Multiple old coatings
Incompatible coatings
Excessive gloss
Powdery surfaces
Previous repairs
A new coating applied over a weak or unsuitable existing coating may eventually fail because the problem is underneath the new paint.
Where appropriate, adhesion and surface-condition testing can help determine whether the existing coating can remain or whether more extensive preparation is necessary.
For larger commercial and development projects, documenting the condition of existing surfaces can also help establish realistic project expectations.
5. Check for Cracks and Structural Movement
Small cracks aren't necessarily the same as major structural defects.
However, every significant crack should be investigated before painting.
Determine:
Is the crack superficial?
Is it caused by movement?
Is water entering through it?
Does it require repair before painting?
Simply filling a crack and painting over it without understanding the cause can result in the crack returning.
Where structural movement or significant building defects are suspected, the appropriate building professional should assess the issue before coating work proceeds.
6. Assess the Level of Surface Preparation Required
One of the biggest mistakes contractors can make is underestimating preparation.
Depending on the condition of the wall, preparation could include:
Cleaning
Pressure washing
Scraping
Sanding
Removing loose coatings
Treating mould or algae
Repairing cracks
Filling imperfections
Priming
Allowing repairs to cure
Removing contaminants
The preparation required should be determined before the quotation is finalised. Otherwise, you may discover halfway through the project that substantially more labour is required than originally estimated.
7. Consider the Local Environment
Exterior walls are exposed to the elements every day.
Consider the conditions affecting the building:
Sun exposure
Rain
Humidity
Wind
Coastal conditions
Pollution
Dust
Temperature
fluctuations
Biological growth
A building in a harsh environment may have very different coating requirements from a protected residential property.
Understanding the environment helps you determine what performance characteristics are important for the project.
8. Check the Weather Before Painting
Even when the surface is properly prepared, weather conditions can affect the application and drying of exterior coatings.
Before starting work,
consider:
Rain forecast
Temperature
Humidity
Wind
Direct sunlight
Surface temperature
Overnight conditions
Don't simply look at whether it is raining at the moment.The conditions before, during and after application can all be relevant.
Always follow the specific manufacturer's technical data and application requirements for the product being used.
9. Calculate the Paint Requirement Properly
Before ordering materials, calculate the actual area to be coated.
Consider:
Wall dimensions
Doors
Windows
Number of coats
Product coverage
Surface texture
Porosity
Wastage
Application method
Highly textured or porous surfaces may require more material than a smooth, well-sealed surface.
Don't base the order purely on building floor area.
A 300m² building does not necessarily have 300m² of paintable exterior wall.
Measure the actual surfaces.
Accurate calculations help reduce both shortages and unnecessary surplus.
10. Decide on the Appropriate Coating System
The final colour is only one part of the decision.
A complete exterior coating system may involve:
Surface preparation → primer/sealer where required → appropriate topcoat → correct application
The correct system depends on the substrate, surface condition, environment and performance requirements.
Before recommending a product, make sure you understand the manufacturer's technical recommendations.
For larger or technically demanding projects, professional technical assistance can be extremely valuable.
11. Check Access and Safety Requirements
Before the painting crew arrives, determine how the painters will safely reach every area that needs to be coated.
Depending on the building, this could involve:
Ladders
Scaffolding
Mobile elevated work platforms
Harness systems
Edge protection
Restricted areas
Traffic management
Access isn't just a safety consideration.It also affects:Labour → productivity → project duration → cost.
If access requirements aren't considered when quoting the project, your original estimate can quickly become inaccurate.
12. Protect Finished Areas
Exterior painting can affect more than the walls.
Plan for the protection of:
Windows
Doors
Paving
Landscaping
Vehicles
Lighting
Signage
Outdoor equipment
Finished surfaces
Overspray, splashes and spills can create additional cleaning and repair costs.
A professional contractor should include protection and cleanup in the project plan.
13. Don't Ignore the Client's Expectations
Before starting, make sure everyone understands what the finished project is expected to look like.
Discuss:
Colour
Finish
Number of coats
Areas included
Areas excluded
Repairs
Preparation requirements
Expected completion date
Access requirements
Weather-related delays
A clear scope of work protects both the contractor and the client.
The Exterior Painting Checklist
Before starting an exterior project, ask:
Surface
☐ What substrate are we painting?
☐ What condition is it in?
☐ Are there cracks or damaged areas?
☐ Is the existing coating sound?
Moisture
☐ Is there evidence of damp?
☐ Have leaks been corrected?
☐ Is the surface adequately dry?
Preparation
☐ What cleaning is required?
☐ What repairs are required?
☐ Is scraping or sanding necessary?
☐ Is a primer/sealer required?
Product
☐ Is the coating suitable for the substrate?
☐ Is it appropriate for the environment?
☐ How many coats are required?
☐ What coverage can realistically be expected?
Project
☐ How much material is required?
☐ What access equipment is needed?
☐ What areas require protection?
☐ What weather conditions are expected?
☐ Has the client approved the colour and scope?
If you can answer these questions before the first coat is applied, you are already reducing many of the risks associated with exterior painting.
The Bottom Line
A professional exterior painting project begins with assessment and preparation—not paint.
The best contractors understand that the quality of the final finish depends on what happens before the paint is applied.
Take the time to inspect the substrate, identify moisture problems, understand the environment, calculate the material requirements and select an appropriate coating system.
And
if you're unsure about an important paint decision, get advice before the materials are ordered or the first coat is applied.
Have an Exterior Painting Project Coming Up?
If you're a contractor, builder or property developer planning an exterior painting project, I can help you work through the important paint decisions before you commit your budget.
Let's discuss your project.
Fabian Drurie-Brewer
Paint Project Specialist
Call / WhatsApp: 068 252 1619
Always consult the relevant manufacturer's technical data sheets and application instructions for the specific coating system being used. Project conditions and substrate requirements should be assessed individually.