Ask any good painter and they will tell you the same thing: preparation is about 80% of a quality paint job. The actual painting is the easy part — it is the prep that decides whether the finish looks flawless or average, and whether it lasts. That is especially true in Melbourne’s period homes, like the ones we paint across Malvern, where decades of patchwork, old plaster and oil-based trim all need handling before a brush touches the wall. Here is how we prep an interior properly.
| Prep step | Why it matters |
|---|---|
| Sand every surface | Removes dust, debris and rough spots so paint sits smooth |
| Fill & smooth patches | Imperfections show in raking light if left |
| Spot-prime patches | Sealed plaster won’t soak up and dull the paint |
| Convert oil-based trim | Water-based won’t stick to old oil paint without it |
| Protect the room | Dropsheets everywhere — paint damages what it lands on |
Prep is 80% of the job
It surprises people how much of a paint job happens before any colour goes on. But cutting corners on prep is the single biggest reason a paint job looks average or fails early. Every step below is about one thing: giving the paint a clean, smooth, sealed surface to grip — so the finish is flawless and it lasts.
Step 1 — Sand every surface
Sanding is the first step to anything. Every wall, surface and area gets sanded back completely, which clears away dust and debris and knocks back any rough spots in the surface. In old Malvern homes especially, walls have had a lot of patchwork over the years, so there is almost always texture and unevenness to smooth out first. Skip the sanding and every one of those rough spots telegraphs through the fresh paint.
Step 2 — Fill and smooth every rough patch
Once it is sanded, any rough patches or imperfections need to be filled and smoothed — because if they are left, they will show. In hallways and sunlit rooms especially, when direct light hits a wall at an angle and refracts across it, every lump and dip becomes obvious. For small, minor imperfections a topping coat is the best way to go: it is a good filling agent, and once it is primed and painted over, those imperfections simply disappear. For anything bigger — cracks or failed plaster — see our guide on what causes cracks and how we repair them.
Step 3 — Spot-prime the patches
Anywhere a topping, base or final coat of plaster has been applied, we spot-prime it before painting. This does two things: it seals the plaster, and — just as importantly — it stops the fresh plaster soaking up the paint. Unprimed plaster drinks the paint straight in, leaving that spot dry, flat and standing out from the rest of the wall. A quick spot-prime is what keeps the whole finish even.
Step 4 — Converting oil-based trim to water-based
Older homes often have oil-based paint on the trim — doors, skirting boards and architraves. You cannot just put water-based paint straight over oil-based; it will not stick. To convert it, we sand the surface back and then apply Dulux Precision Maximum Adhesion Primer, which is designed exactly for this — it lets a water-based topcoat bond properly to the old oil-based trim. Miss this step and the new paint will peel.
Step 5 — Protect everything before you paint
Preparation takes a lot of time, and protecting the space is a non-negotiable part of it. Everything that is not being painted gets covered, and dropsheets go down everywhere paint could drip or land. It sounds obvious, but it is a must-do — anything left uncovered can be damaged by paint, and no one wants speckles on the floorboards or furniture. Good painters treat the room as carefully as the walls.
Why prep matters even more in a period home
Malvern and Melbourne’s other period suburbs are full of beautiful old homes — solid plaster, decades of previous paint, original oil-based trim and years of patch repairs. All of that has to be handled in the prep, or it shows in the finish. Getting it right is exactly what we do on our Malvern painting and property maintenance jobs, and it is why proper prep is worth the time.
Why Melbourne homeowners choose 4P Collective
We treat prep as the job, not the boring bit before it. We sand, fill, prime and protect properly, we use the right products, and we finish so the paint looks flawless and lasts. We are one reliable team across painting, plastering and handyman work, with a 4.9-star rating from 55+ Google reviews. If you want an interior painted properly, call 4P Collective on 0409 215 215.
Frequently Asked Questions
Why is prep so important before interior painting?
Because preparation is roughly 80% of a quality paint job. The painting itself is the easy part — it is the sanding, filling, priming and protecting that decide whether the finish looks flawless and lasts, or looks average and fails early.
Do I need to sand the walls before painting?
Yes. Sanding is the first step to anything — it clears dust and debris and knocks back rough spots so the paint sits smooth. In older homes with a lot of previous patchwork it matters even more, because unsanded texture telegraphs straight through the new paint.
Why do my old patches show through the new paint?
Usually because they were not sanded and filled smooth, or not spot-primed. Unprimed plaster soaks up the paint and dries flat and dull, and any lump or dip shows up when light rakes across the wall. Filling, sanding and spot-priming fix both problems.
Can I paint water-based over oil-based trim?
Not directly — water-based paint will not stick to old oil-based trim. Sand the surface back and apply Dulux Precision Maximum Adhesion Primer first, which is made to let a water-based topcoat bond to oil-based doors, skirting and architraves.
What is a topping coat and when do you use it?
A topping coat is a plastering product that works as a good filling agent for small, minor imperfections. Applied, sanded, primed and painted over, it makes those imperfections disappear — ideal for smoothing a wall before painting.
How long does painting prep take?
It is the biggest part of the job — around 80% of the total time on a quality repaint. Sanding, filling, priming and protecting the room properly takes time, but it is exactly what produces a flawless, long-lasting finish.
A great paint job is made before the first coat goes on. If you would like your Melbourne home painted properly — prep and all — call 4P Collective on 0409 215 215.
