PAVEMENT PROBLEMS
Alligator Cracking: What It Means and Whether Sealcoating Will Help
The pavement has broken into a web of small interconnected cracks that look like the back of an alligator.
What alligator cracking actually is
Alligator cracking is a fatigue failure. The asphalt surface has flexed under load more times than it can take, and it has broken into small connected pieces. You will usually see it in wheel paths, at driveway entrances, in turnarounds, and anywhere heavy trucks stop and turn. The pieces get smaller as the problem gets worse.
Here is the part most people miss. The crack pattern is on the surface, but the problem is underneath it. Asphalt that is properly supported does not fatigue like that. When the gravel base or the soil below it gets soft, the pavement above it has nothing to lean on. It bends, and eventually it breaks.
Why it shows up faster in Truckee and North Tahoe
Water is the whole story at this elevation. Snowmelt runs into cracks, gets into the base, and sits there. Then the temperature drops overnight and that water freezes and expands. It does that over and over from October through May. A base that was tight in September can be loose and pumping by June.
Add the load side of it. Garbage trucks, delivery trucks, propane trucks, and plow rigs all run the same lines on an HOA road. Spring is the worst time for that traffic because the base is saturated and weak right after thaw. That combination is why mountain pavement alligators sooner than pavement down in the valley.
Section thickness plays into it. A driveway built to carry cars will alligator fast if a propane truck or a moving van starts using it regularly. The asphalt did not change. The load overwhelmed what was underneath it.
Can sealcoating fix it? No.
We will give you the straight answer. Sealer is a coating. It is roughly the thickness of a business card. It protects good asphalt from sun, water, and oxidation. It has no structural value at all. Putting sealer over alligator cracking hides the pattern for a few weeks and then the cracks telegraph right back through.
Crack sealing will not solve it either. Hot rubberized crack sealant works beautifully on single cracks with two clean faces. Alligator cracking has dozens of intersecting faces and loose pieces between them. There is nothing solid to bond to. Any contractor who offers to seal an alligatored area and calls it a repair is selling you a paint job.
What actually fixes it, and what we do instead
Real repair means removing the failed pavement, digging out and rebuilding the base underneath, compacting it, and paving back over the top. That is called a dig-out or a remove and replace. It is paving work. Robert E. Sutton Co. does not pave, patch, or overlay. We are a maintenance company. So we will tell you plainly that this one is not ours.
What we can do is protect everything around it. If eighty percent of your lot or road is still sound and twenty percent is alligatored, the smart move is to have a paving contractor rebuild the failed sections, then keep the rest sealed and crack sealed so it never gets there. That sequence saves the most money over time. Call (530) 587-4161 and we will look at it and tell you which parts are worth maintaining and which parts need a paving contractor.
Quick answers
Can I just seal over the alligatored area for now to keep water out?
It will not keep water out. Sealer bridges hairline cracks, not a broken web with loose pieces in it. Water goes right through the joints and into the base. You are better off spending that money on the sound pavement and planning the dig-out.
How fast does alligator cracking spread up here?
Faster than most people expect, because our freeze-thaw season is long and the base stays wet. A small patch that shows up in one spring can double by the next. It depends on drainage and traffic, so call (530) 587-4161 and we will look at it.
Is it worth sealcoating the rest of the lot if one area is failing?
Usually yes. The sound pavement is what you are trying to keep. Letting it oxidize while you wait on a repair budget just means a bigger paving bill later. Maintain what is good, rebuild what is gone.
More in the pavement guides and the FAQ, or see every pavement problem we get asked about.
Not sure what you are looking at?
Send a photo or call (530) 587-4161. We reply within one business day and we will tell you straight whether it is something we can maintain or something that needs a paving contractor.