The short version A tired paver or interlock surface usually has three problems: ground-in dirt and stains on the stones, weeds and moss in the joints, and white efflorescence hazing the surface. All three are fixable without lifting and relaying the whole area. Controlled, low-pressure blasting cleans the stones and clears the joints without dislodging pavers, the efflorescence is removed rather than sealed in, and fresh jointing sand and a sealer finish the job. High-pressure washing is what damages pavers; matched blasting is the safer route.
Interlocking pavers make a beautiful driveway or patio, and after a few Alberta seasons they make a tired-looking one: grey with grime, green in the joints, and hazed with white powder. The instinct is to hit them with a pressure washer on full power, which is exactly what strips the jointing sand, erodes the stones, and leaves a lumpy, loose surface. This guide explains what is actually wrong with a worn paver surface, and how it is brought back without trading one kind of damage for another.
What is actually wrong with a tired paver surface
A worn paver driveway or patio almost always has three separate problems, and it helps to name them, because they call for different steps. The first is on the stones themselves: ground-in dirt, oil and tire marks, and organic staining that has dulled the colour. The second is in the joints: weeds and moss have taken hold, and the jointing sand that locks the pavers together has washed and blown out over the years. The third is efflorescence, the white or cloudy haze that blooms across the surface. A proper restoration deals with all three rather than just hosing the top.
The stones are usually fine. What has failed is the sand in the joints and the finish on the surface, and both can be renewed.
Why efflorescence appears, and why sealing over it makes it worse
That white haze is efflorescence, mineral salts that migrate to the surface of concrete pavers as moisture moves through them and are left behind as a powdery bloom when the water evaporates. It is common on new and aging interlock alike in our climate. The mistake is to seal or coat over it, which locks the cloudiness in permanently, or to attack it with high pressure, which drives it around without removing it. Efflorescence has to be lifted off the surface before anything else is done, which is something controlled blasting does cleanly.
Why high-pressure washing damages pavers
A pressure washer turned up high enough to clean stained pavers is also strong enough to blast the jointing sand out from between them and to erode the face of the stones. Losing the joint sand is the real damage, because that sand is what locks an interlocking system together: once it is gone, individual pavers begin to shift, rock, and heave, and the tidy surface turns lumpy and loose. The cleaning that was meant to renew the driveway ends up loosening it. The answer is a method whose aggression can be controlled and matched to the surface rather than a single blunt setting.
Cleaning without dislodging the stones
Controlled, low-pressure blasting with matched media cleans the faces of the pavers and clears organic growth and old, spent sand from the joints without the blunt force that pops stones loose. The pressure and media are dialled to lift the grime, stains, and efflorescence while leaving the pavers seated, and a test area confirms the setting before the whole surface is done. The media choice is covered in our guide to the right blasting media for every surface, and the wider method in our comparison of dustless blasting and sandblasting.
Re-sanding the joints
Cleaning is only half of a paver restoration. Once the joints are cleared and the surface is dry, they are refilled with fresh jointing sand, and a polymeric sand that hardens in place is often the better choice because it resists washing out and discourages weeds from returning. Refilling and setting the joints is what restores the interlock, locking the pavers back together so the surface stays flat and stable. Skipping this step leaves a clean but loose driveway that will shift again within a season.
Sealing pavers for our climate
With the pavers clean and the joints re-sanded, a sealer protects the finish and helps stabilise the joint sand. A penetrating sealer suits our freeze-thaw climate, soaking in to protect the stone and resist staining without forming a glossy film that can cloud or peel, and it slows the return of efflorescence and organic growth. As with concrete, the sealing is timed to a dry, warm stretch so it cures properly. The same reasoning is covered in our guide to restoring exposed-aggregate and decorative concrete.
Weeds, moss, and why they came back
Weeds and moss in the joints are a symptom as much as a problem. They take hold where old sand has broken down and where shade and moisture let them, so clearing them is part of the clean, and re-sanding with a stabilising sand and improving drainage is what keeps them from marching straight back. A restoration that only pulls the weeds without renewing the joints is a short-lived one.
How we approach a paver restoration
We start by assessing the surface and running a test spot to set the gentlest media and pressure that clean the stones and clear the joints without unseating pavers. The surface is cleaned with controlled blasting, the efflorescence and old sand are removed, the area is allowed to dry, and the joints are refilled and the surface sealed, or handed back clean and ready if you prefer to finish it yourself. Throughout, the work is contained so the property is left tidy. For homeowners restoring poured concrete alongside their pavers, our guide to restoring a spalling concrete driveway covers that surface.
Frequently asked questions
Can you clean pavers without loosening or dislodging them?
Yes, with a method whose aggression is controlled. Low-pressure blasting with matched media cleans the stones and clears the joints without the blunt force of a high-pressure washer, which blasts out the jointing sand and lets pavers shift. A test spot confirms the setting first.
What is the white haze on my pavers, and can it be removed?
It is efflorescence, mineral salts drawn to the surface as moisture moves through the pavers. It can be removed, but it has to be lifted off rather than sealed over, because coating over it locks the cloudiness in. Controlled blasting removes it cleanly.
Should pavers be re-sanded after cleaning?
Yes. The jointing sand locks an interlocking system together, and cleaning removes the old, spent sand. Refilling the joints, often with a polymeric sand that hardens in place, restores the interlock so the pavers stay flat and stable and weeds are discouraged.
Is pressure washing bad for interlock?
High-pressure washing is the most common way pavers get damaged. It blasts the joint sand out and erodes the stone faces, which lets pavers shift, rock, and heave. Controlled blasting cleans without that blunt force.
Do interlock pavers need to be sealed in Alberta?
Sealing is not mandatory, but it helps. A penetrating sealer protects the stone, stabilises the joint sand, and slows efflorescence and staining, and it holds up to our freeze-thaw better than a glossy film sealer. It is applied once the surface is clean, re-sanded, and dry.