Interlock questions, answered straight.

Almost always the base under them, not the pavers themselves. Over time the bedding can wash out, a tree root can lift and then decay under a section, or a base that was not properly compacted during the original install finally gives. In St. Catharines, clay soil holding water through a freeze-thaw winter accelerates all of these. The pavers are usually perfectly reusable once the base is rebuilt properly. See the re-leveling guide for a full breakdown.

No. Weeds in the joints mean the joint sand washed out and left a gap where soil and seeds can accumulate. The fix is clearing the joints and refilling them with polymeric sand, which hardens and leaves no hospitable gap for weed germination. It is the least expensive restoration job on this guide. More detail on the joint sand page.

Roughly 3 to 5 years in St. Catharines and Niagara before the sealer wants refreshing, depending on traffic, sun exposure, and winter salt. A driveway that takes daily vehicle traffic and road salt is at the shorter end; a shaded patio with foot traffic only is at the longer end. The refresh cycle is lighter than the original seal job because the cleaning pass is less intensive the second time around. More on the cleaning and sealing page.

For most properties, yes, by a wide margin. A full restoration, re-leveling the settled spots, re-sanding the joints, cleaning and sealing the surface, illustratively runs around a third to a half of what tearing out and laying new interlock costs, because the pavers you already paid for are almost always reusable. The cost guide has a worked example comparing a typical 500 sq ft St. Catharines driveway either way.

For the odd cracked or spalled paver, a good contractor will check whether the style is still in production and source the closest available match. When pavers are being re-laid back into the existing field, a replacement blends in better than most homeowners expect because the whole surface goes through the same cleaning and sealing pass. For a discontinued style, the honest options include sourcing the closest current match, pulling matching pavers from a less visible part of the same surface, or a combination of both. Ask the contractor to explain the plan before work starts.

Late spring through early fall, during dry stretches. Polymeric sand and sealer both need a dry surface and a clear forecast to cure correctly. Summer dry periods are the prime window and also when contractor calendars fill. If restoration is on the list for the season, reaching out to contractors early gives better odds of a date that works.