How do I refresh polymeric sand in my Vancouver paver joints?

Refreshing polymeric sand in Metro Vancouver is one of the most valuable DIY maintenance tasks you can do for your interlock — and in this climate, you'll likely need to do it every 3-5 years.

Vancouver's 1,200mm+ of annual rainfall (and significantly more on the North Shore) is relentless on paver joints. Even quality polymeric sand breaks down over time from rain erosion, UV exposure, and the freeze-thaw cycles we do get. When joints start looking hollow, moss is creeping in, or pavers are rocking slightly underfoot, it's time to refresh.

Step 1: Clean the Surface Thoroughly

Start with a thorough pressure wash — 1,500 to 2,500 PSI with a rotating surface cleaner attachment works well on concrete pavers. The rotating head prevents the striping pattern you get from a standard wand. This removes moss, algae, dirt, and the remnants of old degraded sand. If you have significant moss growth (very common on north-facing or shaded patios in Metro Vancouver), treat with an iron sulphate or zinc sulphate-based moss killer a week before washing, let it die off, then pressure wash. Do not use chlorine bleach — it damages polymeric sand, discolours pavers, and kills surrounding plants.

After washing, let the surface dry completely. In Metro Vancouver, this means watching the forecast and waiting for a genuine dry window — ideally 48 hours of dry weather before you apply new sand.

Step 2: Remove Old Sand from the Joints

Use a stiff-bristled broom, a joint scraper, or even a flat-head screwdriver to clear out the top portion of degraded old sand. You don't need to excavate the full joint depth — just remove enough to create 1 to 1.5 inches of empty joint space for the new polymeric sand to fill and bond properly. If you leave a thick layer of old broken-down sand, the new material won't bond well and will fail prematurely.

Step 3: Choose the Right Polymeric Sand

This is not the place to cut corners. In Metro Vancouver's wet climate, budget polymeric sand from a big-box store performs noticeably worse than professional-grade products. Techniseal HP Polymeric Sand, Alliance Gator Maxx G2, and Sakrete PermaSand are the products local installers trust. Choose a colour that matches your existing joints — typically beige/tan for most concrete pavers, or grey for darker pavers.

Step 4: Apply and Sweep In

Pour the polymeric sand onto the dry paver surface and sweep it into the joints with a stiff push broom, working in multiple directions to fill every joint completely. You want joints filled to within about 1/8 inch of the top of the paver — not flush, not overflowing. After sweeping in, run a plate compactor over the surface (with a rubber protective pad underneath — never run a compactor directly on bare pavers) to settle the sand and vibrate it deep into the joints. Sweep in a second pass to top up any joints that settled during compaction.

Blow or brush off all excess sand from the paver surface before activating. Any polymeric sand left sitting on the surface when you add water will haze and bond to the pavers — this is one of the most common mistakes and it's very difficult to fix once cured.

Step 5: Activate with Water — Carefully

This is the step most DIYers rush. Use a garden hose with a gentle spray setting — not a pressure washer, not a hard jet. You want to wet the joints thoroughly without blasting sand back out. Make two or three passes over the entire area, letting the water soak in between passes. The sand will visibly darken and begin to firm up. Follow the manufacturer's instructions for your specific product — most require the surface to stay dry for 24 hours after activation to cure properly.

Check the forecast before you activate. If rain is coming within 24 hours, wait. Activating polymeric sand and then getting rained on before it cures washes the binder out and you're back to square one. In Metro Vancouver between October and March, this means watching Environment Canada closely and picking your window carefully.

Once cured, the joints should feel firm — not rock-hard like concrete, but noticeably more stable than loose sand. Properly applied polymeric sand in Metro Vancouver should last 3-5 years before needing another refresh.

If your joints are deeply eroded, pavers are shifting, or you're seeing widespread settling across a large area, that points to a base drainage issue beneath the surface — at that point, it's worth having a professional assess whether relevelling is needed rather than just resanding.