Usually yes — but almost never straight away, and not on every driveway. Sealing traps whatever is underneath it, so the decision is really about two things: whether your concrete is dry enough, and whether sealing suits the surface you actually have.
Most advice you’ll find on this question is written for North America. That matters more than it sounds, because the single biggest variable is how long concrete takes to dry — and Brisbane’s humidity changes that answer considerably.
Why you can’t seal a freshly cleaned driveway
Pressure cleaning drives a surprising amount of water into concrete. Concrete is porous; it behaves a bit like a very dense sponge. After a thorough clean, moisture sits in the top few millimetres of the slab and takes days to leave.
Seal over that moisture and it has nowhere to go. The result is a milky white haze under the sealer — sometimes called blushing or blooming — and it is not a surface problem you can buff out. Once the sealer has cured over trapped moisture, fixing it means stripping the sealer off and starting again, which costs more than the original job.
The second problem is biological. If any mould, algae or lichen survived the clean, sealing puts a clear coat over living organic matter. It keeps growing underneath, and you end up with dark patches suspended under a glossy finish. This is why a proper clean matters before sealing — we cover what that involves in removing mould from concrete.
How long to wait in Brisbane
Generic guidance says 24 to 48 hours. In Brisbane that is often not enough.
What actually governs it is how quickly moisture can leave the slab, and that depends on humidity, temperature, sun exposure and how deep the water went. A north-facing driveway in dry winter conditions might genuinely be ready in two days. The same driveway in February, after a humid week, can still be holding moisture after five.
A practical test beats counting days. Tape a square of clear plastic sheet — around 400mm x 400mm — flat to the concrete, sealing all four edges with masking tape. Leave it for 24 hours in the shade. If condensation forms underneath, or the concrete beneath it darkens, the slab is still releasing moisture and is not ready. Repeat daily until the plastic stays dry.
It is a slow test, and it is far cheaper than stripping a failed seal.
When sealing is worth doing
- Exposed aggregate and decorative concrete. These have more surface area and more places for dirt to lodge. Sealing genuinely reduces how quickly they re-soil, and brings back the colour depth in the stone.
- Driveways that see oil. A sealed surface gives you time to lift a drip before it penetrates. On unsealed concrete, oil is into the pores within minutes.
- Concrete that has just been cleaned properly. Cleaning opens the pores. That is the moment the surface is most receptive to a sealer, and also the moment it is most vulnerable to staining if you leave it bare.
- Shaded, damp areas. The south side of a house, under trees, anywhere that stays wet — these are where mould returns fastest, and where a sealer buys you the most time.
When it is not the right call
- The slab is already sealed. Applying a new sealer over an old one that is failing will lift and flake. Old sealer needs stripping first, which is a separate job.
- There is a drainage problem. If water pools on the driveway, sealing does not fix it — it just makes a pooling area slippery. Fix the fall first.
- The concrete is spalling or cracking badly. Sealing over structural deterioration hides it rather than addressing it, and you will be looking at the same problem with a shiny finish.
Penetrating or topical — the trade-off nobody explains
Sealers fall into two broad families and they behave completely differently.
Penetrating sealers soak into the concrete and work from within. They leave the surface looking essentially unchanged — matte, natural, no shine — and they do not peel, because there is no film sitting on top. They are more forgiving of slight moisture and they keep the surface slip-resistant. For a plain concrete driveway in a wet climate, this is usually the sensible choice.
Topical sealers form a film on the surface. They give you the wet-look or gloss finish people often want on exposed aggregate, and they resist staining well. The trade-offs are real: they can be slippery when wet, they show wear where tyres turn, and when they eventually fail they fail visibly, flaking rather than fading.
Neither is objectively better. The gloss finish that looks superb on a decorative entertaining area is a poor decision on a steep, shaded driveway that gets wet.
How often it needs redoing
Sealers are consumables, not permanent. Penetrating sealers typically hold for several years; topical sealers usually need attention sooner, particularly in the wheel tracks where tyres scrub the film.
Brisbane’s conditions are harder on sealers than most of Australia — intense UV through summer, then months of humidity and rain. Plan on periodic reapplication rather than treating it as done once. The practical signal is simple: when water stops beading and starts soaking in, the sealer has stopped working.
The order that works
- Clean the surface properly, including treating any mould or algae rather than just blasting it
- Let it dry fully — test with plastic sheet rather than guessing
- Address oil stains separately; sealer will not hide them
- Choose the sealer type to suit the surface and how the area is used
- Apply in dry, mild conditions, not in direct summer heat and not with rain forecast
Skipping straight from step one to step five is how most sealing jobs fail, and it is why so many people conclude that sealing “doesn’t work”. It usually did work — it was just applied to a slab that wasn’t ready.
Not sure which applies to your driveway?
If you’re weighing this up, the honest first step is finding out what condition the concrete is actually in — whether it’s previously been sealed, how porous it is, and whether there’s mould that needs treating first. That’s a look, not a guess. Read more about what driveway cleaning involves, or request a free quote and we’ll tell you plainly whether sealing is worth it on your surface — including when it isn’t.
