SRW WetLok Jointing Sand: Rain Day Install Guide, 1/8 in to 5 in

SRW WetLok is the SRW Products jointing sand for jobs where the weather will not cooperate. Instead of a dry polymeric sand that has to be activated on a dry surface, WetLok comes premixed in a 36 lb tub, air cures on its own schedule, and can go in during a light rain. Once it sets, the joint is permeable, so water drains through instead of ponding. SRW rates it for joints from 1/8 in all the way to 5 in, which covers tight paver joints and wide flagstone gaps with one product.

This guide covers what WetLok is, the surfaces and bases SRW lists for it, the limits from the SRW data sheet, the four step installation, coverage per tub and the questions we hear most, using figures from the SRW WetLok product page and technical data sheet.

What SRW WetLok is

SRW WetLok Permeable Jointing Sand is not a polymeric sand, and it behaves differently at every stage of the job. Here is how it compares with a typical water activated polymeric sand:

Feature	Typical polymeric sand	SRW WetLok
How it sets	Dry sand, activated with water after it is in the joint	Premixed, air cures on its own schedule
Weather	Damp joints, surprise showers and cold snaps can ruin the cure	Light rain during installation is fine; cover it in heavy rain
Water through the joint	Water sheds off the joint	Permeable after set, water drains through
Joint range	Varies by product	1/8 in to 5 in with one product
Leftovers	Opened bags need dry, covered storage	Keep in the original tub under 2 in of water, lid sealed
Packaging	Usually 50 lb bags	36 lb tub, five colors

SRW's pitch is simple: polymeric sand punishes bad timing, and the redo costs more than the sand did. WetLok takes timing out of the equation. For a broader look at the two categories, read our comparison of polymeric sand vs resin sand.

SRW WetLok specifications

Specification	Per SRW
Joint width	1/8 in to 5 in
Installation temperature	Above 37°F
Rain during or after installation	Light rain is fine; cover the install in heavy rain so fresh sand does not wash out before curing
Plate compactor	Not recommended
Pressure washing	Not for at least 14 days after installation
Drainage	Required; overlays without proper slope or drainage can keep WetLok from curing properly
Shelf life	12 months with proper storage and undamaged packaging
Tub size	36 lb
Colors	Tan, Granite, Black, Platinum, Beach
Uses	Patios, walkways, pool decks, light duty residential interlocking paver driveways, residential and commercial

SRW does not publish a walk on or full cure time on the product page, so we do not state one here; check the manufacturer data sheet in our TDS and SDS library. SRW also notes that actual color varies by geographic location and every monitor shows color differently, so compare the WetLok color samples on your own stone before ordering full tubs.

Where to use it (and where not to)

SRW Products recommends WetLok for joints from 1/8 in to 5 in in residential and commercial installations on:

• Concrete and clay pavers, wetcast, natural stone and terracotta
• Porcelain tile, for pedestrian use, following SRW's porcelain instructions
• Light duty residential interlocking paver driveways
• Patios, walkways and pool decks
• Traditional, hybrid or open graded bases, including HexaBase installs

Because WetLok is permeable and air cures, it needs drainage to cure against. Per the SRW technical data sheet, overlays without proper slope or drainage can keep it from curing properly, and standing water with no drainage is the one thing that slows the cure. Two more limits from the data sheet: a plate compactor is not recommended with WetLok, and the joints should not be pressure washed for at least 14 days after installation. Install with temperatures staying above 37°F.

For heavier vehicle traffic than a light duty residential driveway, SRW's directions do not cover WetLok. Call (856) 418-4895 and we will point you to a polymeric sand instead, such as SRW Pavermate Z3, which SRW lists for driveways.

How to install SRW WetLok

The full procedure is in the SRW technical data sheet. This is the shape of the job as SRW describes it in the data sheet. Install above 37°F, give the joints drainage to cure against, and always test in a small, discrete area first.

1. Wet. Wet the surface and keep it saturated through the entire process, so the resin does not bind to the paver face.
2. Fill. Pour WetLok in a pile on the wet surface, then immediately wet it down while a second person pushes it diagonally across the joints until each joint is full.
3. Rinse. Rinse the surface until the water runs clean. Do not use a plate compactor.
4. Store. Save the original tub for leftovers: fill it until the water is 2 in over the top of the material and seal the lid. Any exposure to air starts the cure.

Light rain during installation is fine; in heavy rain, cover the installation so fresh sand does not wash out of the joints before it cures. If temperatures can drop below freezing during the install, SRW allows a dry installation, but it raises the chance of enhancement or resin deposits on the surface. Wear gloves and eye protection, follow the label, and keep the product away from children and pets until it is placed or cured. Full precautions are in the SDS. If you are building the base at the same time, our guide on bedding layer and joint sand installation covers the layers underneath.

How much SRW WetLok you need

Joint width drives everything with a product rated from 1/8 in to 5 in. Per the SRW technical data sheet, one 36 lb tub covers:

Surface or joint	Coverage per 36 lb tub
Pavers	45 to 65 sq ft
Larger flagstone	75 to 110 sq ft
1/8 in joints	About 65 sq ft
3/4 in joints	About 13.5 sq ft
1 in joints	About 10.6 sq ft

For an exact tub count, run your paver size and joint width through our polymeric sand calculator, or call (856) 418-4895. Order before our daily cutoff and WetLok ships same day from our New Jersey warehouse. Local pickup is also available: call first, pick up at 1287 Glassboro Road, Williamstown, NJ 08094. Details are on our local pickup page.

Watch the manufacturer's video

Frequently asked questions

Can I really install WetLok in the rain?

In light rain, yes. SRW says installation during a light rain can be done without issue, but a heavy rain may call for covering the installation so fresh sand does not wash out of the joints before curing. Standing water with no drainage also delays the air cure.

Is WetLok OK for porcelain?

Yes, for pedestrian areas, following SRW's porcelain instructions.

Can WetLok go on a driveway?

Light duty residential interlocking paver driveways, per SRW's directions. For heavier vehicle use, ask us about a polymeric sand instead.

When can I pressure wash WetLok joints?

Not for at least 14 days after installation, per the SRW technical data sheet.

What do I do with the leftover material?

Save the original tub, fill it until the water is 2 in over the top of the material and seal the lid, since any exposure to air starts the cure. Stored with care in undamaged packaging, WetLok has a 12 month shelf life, so you can keep it for repairs and touch ups.