Sunken asphalt repair in Edmonton, with the base rebuilt
A dip means something underneath moved or disappeared. Pouring asphalt into it restores the level and leaves the cause in place, which is why these come back and why we do not repair them that way.
What a sunken area in Edmonton asphalt is telling you
Three things cause almost all of them. A service trench that was backfilled loosely and has been consolidating ever since. Granular that water has carried away from under the surface. Or subgrade that was never strong enough and has compressed under traffic.
The shape is a clue. A long narrow depression running across a drive is nearly always a trench. A rounded dish near an edge or a downspout is usually washed base. A broad shallow area under where vehicles sit is compressed subgrade.
Filling the dip with asphalt treats none of these. The new material adds weight to ground that is already failing and the depression reappears, usually deeper. The base has to be opened and rebuilt, which is why this is quoted as a patch rather than a fill, and why the economics change when there are several.
Lifted section
How it runs
How a sunken Edmonton asphalt section is repaired
Work out what moved
Shape, position and history point at a trench, washed granular or weak subgrade, and each one needs something different done about it.
Cut and lift the section
The depressed area is saw-cut past its edges and removed, which exposes the void or the soft material that caused it.
Rebuild the layer below
Loose backfill is removed and replaced with compacted granular in lifts. Where the subgrade itself is the problem it is dug deeper and stabilised.
Relay to the correct level
New asphalt is placed and compacted to the surrounding grade, with the finished level checked against where water needs to run rather than against the old dip.
After the repair
Will a repaired Edmonton sunken area settle again
If the cause was a trench and the backfill has been replaced and compacted properly, no. The material that was consolidating has gone, and what replaced it was compacted in layers rather than shovelled in and driven over.
If the cause was water, the repair only holds once the water is dealt with. Rebuilding the base under a spot that is still being washed is a slower version of the same failure, so the drainage comes first.
Weak subgrade is the hardest of the three. Sometimes it needs digging deeper than the asphalt job suggests, and occasionally the honest answer is that the area needs rebuilding properly rather than repaired. Getting the fall right is part of either.
FixableTrench
Fix that firstWater
Dig deeperSubgrade
Related repairs
Repairs connected to settlement in Edmonton
A dip is usually a symptom of something on this list.
It restores the level for a while and leaves the cause untouched. The added weight on ground that is already moving usually means the depression returns deeper than before.
That shape almost always means a service trench. Backfill that was not compacted in layers consolidates for years afterwards, and the surface above it simply follows the ground down as it goes.
It is both a symptom and an accelerant. Water collects because the area sank, then it softens the base further, so the dip deepens faster than it otherwise would.
As deep as the loose or saturated material goes. A trench may be most of a metre; a washed area under a downspout is often much shallower than people expect.
Yes, as a rectangle of darker asphalt with sealed joints. It fades through the first season and a coat over the whole surface afterwards evens it out.
Then the base is likely to be the problem across the surface rather than in spots, and rebuilding the area properly usually costs less than repairing each dip in turn.
Get a sunken Edmonton driveway or lot section looked at
We will work out what moved underneath, rebuild it rather than cover it, and tell you if the pattern across the surface means something larger is going on.
