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Painting Advice

Surface Preparation & Repairs

Good painting starts well before the first coat goes on. Cleaning, sanding, patching, filling, sealing, priming, and repairing damaged areas all play an important role in achieving a smooth, durable and professional finish.

1. Why Surface Preparation Matters

Surface preparation is one of the most important parts of any painting project. Even quality paint will struggle to perform properly if it is applied over dust, grease, loose paint, damaged plaster, damp areas, or unstable surfaces.

Proper preparation helps improve adhesion, coverage, finish consistency, and long-term durability. It can also reduce the risk of peeling, patchiness, bubbling, flashing, rough texture, and visible defects after painting is complete.

Whether the project involves interior walls, ceilings, timber, render, brick, repaired plaster, or previously painted surfaces, the condition of the substrate should be checked before top coats are applied.

2. Cleaning and Washing Before Painting

Some surfaces only need light dusting, while others need proper washing before painting can begin. Dirt, grease, mould, chalking, cooking residue, smoke stains, and weather exposure can all affect paint adhesion.

Interior Cleaning

Interior areas may need sugar soap, light washing, or simple wipe-down cleaning where surfaces have grease, fingerprints, kitchen residue, bathroom build-up, or general dirt.

Exterior Washing

Exterior walls, eaves, fascia, gutters, weatherboards, fences, and roofs often need more thorough cleaning due to dust, mould, cobwebs, chalking, moss, or weather-related build-up.

When It Matters Most

Washing is especially important before repainting glossy surfaces, wet areas, smoke-affected areas, mould-prone ceilings, and exterior areas exposed to Melbourne’s changing weather.

3. Sanding, Scraping and Paint Removal

Sanding and scraping are often required to smooth rough patches, remove loose material, dull glossy finishes, and prepare the surface for better bond.

If old paint is peeling, flaking, blistering, or lifting at the edges, those loose sections usually need to be scraped back and feather sanded before recoating. Painting over unstable paint often leads to further failure later on.

Sanding is also commonly used on patch repairs, timber trims, doors, skirting boards, frames, and glossy surfaces where extra key is needed. The aim is not just to remove defects, but to create a sound and even base for the next stage.

4. Filling, Patching and Minor Repairs

Small holes, dents, chips, surface damage, and uneven sections often need filling or patching before paint is applied. This helps improve both the appearance and uniformity of the final finish.

Minor Filling
Small nail holes, light dents, shallow damage, and minor surface marks often need filling before sanding and painting.
Patching
Larger damaged areas may require patching, rebuilding corners, repairing loose sections, or replacing damaged surface material before coating.
Correct Product Choice
Different fillers may be better suited to interior, exterior, dry, wet, flexible, or weather-exposed areas depending on the substrate and repair size.

5. Priming and Sealing

Not every surface needs the same primer or sealer. Some areas can be painted directly after preparation, while others require specific products to improve adhesion, reduce absorbency, or isolate stains.

Bare and Porous Surfaces

New plaster, repaired sections, bare timber, masonry, and fresh render often need a suitable primer or sealer before finish coats go on.

Stains and Problem Areas

Water stains, nicotine, smoke, tannin bleed, or repaired sections may need sealing before repainting to help prevent marks showing back through the finish.

Better Finish Consistency

Primers and sealers can help reduce patchiness, improve top coat coverage, and create a more consistent final appearance across repaired or mixed surfaces.

6. Plaster Repairs and Crack Treatment

Plaster repair work often requires more than simply filling a hole. Cracks, joint movement, separated areas, damaged corners, patch marks, and old repairs may need a more careful process before painting.

Some cracks are only cosmetic, while others may indicate movement or previous repair failure. Depending on the area, proper treatment may involve opening the crack slightly, filling, jointing, sanding, sealing, and allowing suitable drying time before recoating.

Damaged plaster around sockets, corners, joins, or repaired wall sections can also require more than one stage of preparation. The goal is to restore the surface so the repair blends in properly once painted.

7. New and Unpainted Surfaces

New surfaces often need a different approach from standard repainting. A surface may look ready, but still require curing time, light sanding, primer, or sealing before finish coats are applied.

New Plaster

Fresh plaster can be very porous and may need proper sealing before finish coats. Without correct preparation, the paint system may not bond or cover consistently.

Unpainted Timber

Bare timber may require sanding, dust removal, stain blocking where needed, and a suitable undercoat or primer depending on the final coating system.

Fresh Render or Masonry

New render, cement-based surfaces, or other mineral substrates may require drying time and appropriate sealing before painting.

8. Interior vs Exterior Preparation

Interior and exterior preparation are often quite different. Internal areas usually focus on cleanliness, repair quality, stain treatment, and finish consistency, while external areas must also account for weather, moisture, movement, and long-term exposure.

Interior preparation often includes patching, sanding, caulking, stain sealing, dust removal, and correcting visible defects under lighting. Exterior preparation may involve washing, mould removal, scraping, weather checking, sealing bare sections, repairing timber, and choosing products suited to Melbourne’s temperature changes and exposure.

Because exterior coatings are exposed to sun, rain, wind, and seasonal changes, preparation quality is especially important for long-term performance.

9. Common Preparation Mistakes

Many coating problems start before the first finish coat. Some of the most common issues happen when preparation is rushed, skipped, or the wrong materials are used.

Painting Over Dust or Grease
This can reduce adhesion and lead to premature failure, especially on glossy, damp, or contaminated surfaces.
Skipping Primer Where Needed
Bare or repaired areas may absorb top coat differently, causing patchiness, flashing, or poor bond if not sealed correctly.
Ignoring Loose Paint or Damage
Painting over unstable surfaces often leaves the underlying problem in place and can shorten the life of the whole system.

10. What Can Affect Time and Scope

Preparation time depends on more than just the size of the area. Surface condition, repairs, coating failure, access, previous paint type, moisture, drying time, and weather can all affect how much work is required.

A simple repaint on a sound surface is very different from a job involving peeling paint, damaged plaster, exterior weathering, mould, stains, or timber repairs. This is one reason quotes may vary depending on surface condition and access.

The better the surface is prepared, the stronger the base for the finish coats and the better the long-term result is likely to be.

11. When to Get Professional Advice

Some areas are straightforward, while others benefit from experienced assessment before painting starts. This is especially true where there is peeling paint, old water damage, cracking, mould, damaged plaster, weathered timber, or uncertain surface condition.

Before a Repaint

If the surface is uneven, glossy, stained, patched many times, or affected by old paint failure, it is worth checking what preparation is needed first.

Before Using New Products

Different surfaces and coatings do not always work the same way. Advice on primer, filler, sealer, and top coat compatibility can help avoid issues later.

Before Exterior Work

Exterior areas exposed to weather, moisture, sun, or movement often need more planning than they first appear to.

12. Get a Free Quote

If your project needs cleaning, sanding, patching, filling, sealing, priming, plaster repairs, repainting, or general surface preparation, Rasa Painting Service can help.

We can provide practical advice based on the condition of your surfaces and help you understand what is needed before painting starts. A well-prepared surface gives the best chance of a cleaner finish and a longer-lasting result.

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