Crack Sealing vs Leave It — When Small Cracks Become Potholes
- PotholeExpert
- 4 days ago
- 5 min read
Every pothole we patch started as a crack 12 to 24 months earlier. The decision committees and owners face is rarely "seal or not seal" — it's "seal now or seal next year". And every winter you wait, the maths gets worse. This is the honest framework.
Crack sealing is a Rapidpatch preventative-maintenance service. Auckland direct service is available now — we'll come back to you within 24 hours with a fixed-price quote from a few photos.
Outside Auckland, we're onboarding approved-partner specialists region by region. 5-business-day response with quote and ETA. Same Rapidpatch fixed-price discipline, same 12-month workmanship guarantee on Rapidpatch-installed work. Urgent or large jobs — phone (027) 737 2858.
Fair Trading Act backup: if we can't match you with a vetted partner in your region, we'll refer you to an independent specialist or return your photos and quote at no cost, no obligation.
The lifecycle: crack → water → base softening → pothole
A 2 mm surface crack in March looks harmless. By May, the autumn rain has been running into it for two months. By July, the granular base material immediately under the crack has saturated and softened. By the first heavy traffic event after that — a delivery truck, a removal van — the softened base displaces under load and the surface above it starts to fragment. By the following March you have a pothole.
That's the entire mechanism. Crack sealing breaks it at step one by stopping the water getting in. It does not strengthen the asphalt. It does not fix anything cosmetic. It just stops the water.
Decision framework: seal now, monitor, or patch later
Hairline cracks under 2 mm wide, no pattern: monitor. Photograph the worst spots and check again in 12 months. If they've widened, seal next spring.
Linear cracks 2–6 mm wide following wheel paths, kerb lines, or seal joins: seal now. This is the highest-ROI window for crack sealing — enough crack to bond into, not so much that water has already done damage.
Cracks 6–10 mm wide: still seal-able, but timing matters. If there's no edge crumbling and the surface is otherwise sound, seal this season. If you wait through another winter you're likely past the seal-able window.
Cracks wider than 10 mm or with edges that crumble when pressed: past seal-able. Plan a patch.
Alligator pattern (interconnected polygons in wheel paths): structural failure, not surface ageing. Sealing won't help — the base underneath is already compromised. Patch now or plan a relay.
Block cracking (whole-surface rectangular pattern): seal-able if the cracks are still narrow, but at this stage you're often within 2–3 years of a full reseal decision anyway.
What "leave it" actually costs
A 5–10 metre run of linear cracking that costs a few hundred dollars to seal today becomes a patch job in 12–18 months, and a patch job is typically several multiples of the seal cost. If the patch is missed and the failure progresses, the same area can become a multi-thousand-dollar full-depth repair within another year.
The compounding only stops when someone patches it. Until then, every winter widens the failure zone, and the cost steps up at each transition: crack → patch → multi-patch → partial resurface → full relay.
When NOT to seal
Sealing the wrong cracking is wasted money. The two clearest "don't seal" cases:
Alligator cracking in wheel paths — the base is gone. Sealing the surface won't reverse base failure.
Cracking around an area where the asphalt visibly moves under load — you have structural failure, not surface ageing. Patching with base remediation is the only honest fix.
Whole-of-surface cracking on asphalt aged 15+ years where a full reseal is already on the LTMP within the next 2–3 years — spend the money on the reseal, not a holding-pattern seal.
The body-corp and commercial maintenance angle
Year 3 to year 5 of an asphalt surface's life is the sweet spot for proactive crack sealing. The substrate has settled, any defects-liability period is done, and the first linear cracks are starting to show at drainage joints, kerb edges, and seal lines. A single afternoon of crack sealing in this window typically extends the surface life by 3–5 years and defers the first patch into year 8–10 instead of year 5–6.
For body-corp committees: this is the cheapest line item in the entire asphalt lifecycle. It almost always falls under delegated authority and should not require an AGM resolution. Build it into the long-term maintenance plan as a recurring year-3-and-year-6 line, not as an ad-hoc reaction.
Pricing
Pricing depends on the linear metres of cracking, the surface type (asphalt vs chipseal), and site access. Crack sealing is a fast service to deliver, so it's usually significantly cheaper than the patching costs it prevents. Send a few photos and we'll come back with a fixed price within 24 hours.
Common questions
How wide is too wide for crack sealing?
Anything wider than about 10 mm, or anything with edges that crumble when you press them with a finger. Past that, hot-pour sealant can't bond properly and you're better spending the money on patching.
How often should I crack-seal my carpark?
A good crack seal lasts 5–8 years. A typical body-corp asphalt cycle gets two seal passes — one at year 3–5, another at year 9–11. Anything more frequent than that and you're spending money on cosmetic touch-ups; anything less frequent and you're paying the gap in patch costs.
Will the seal lines be visible after?
Yes — sealed cracks stay visible. They look like dark lines roughly 10–15 mm wide along the original crack path. It's functional, not cosmetic. If appearance matters, sealcoating or fog-sealing the whole surface 6 weeks after crack sealing evens out the look.
Is it worth sealing one or two cracks, or only worth it on a bigger run?
There's a minimum-job cost — we have to mobilise the gear regardless. For very small jobs we may quote a higher per-metre rate, or we may suggest you wait until there's a 10–metre-plus run to do at once. Honest answer comes back with the quote.
Can I crack-seal chipseal as well as asphalt?
Yes — hot-pour sealant works on both. Chipseal cracking is often broader and shallower than asphalt cracking so the sealant volume per metre is higher, which we factor into the quote.
Do you do this nationwide?
Auckland direct, the rest of NZ via our approved-partner network. 5-business-day quote turnaround outside Auckland. If we can't match you with a partner in your region we'll refer or return your quote at no cost.
Get a fixed-price quote
Send us a few photos from your phone and we'll get a fixed-price crack-seal quote back within 24 hours during business hours. Phone (027) 737 2858 or fix@rapidpatch.co.nz.
Want more context? Read the Crack Seal & Repair service overview or the body-corp 12-year maintenance roadmap.
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