Nurserymen's Preferred® Weed-Blocker


Weed-Blocker Paver Locking Sand (BOM #109551) is a specially formulated polymer modified joint sand for use with pavement systems utilizing segmental concrete pavers, clay pavers or natural stone; concrete slab joint applications or filling gaps between segmental retaining wall blocks. Designed for average joint widths of 1/4" to 3/8" wide, Paver Locking Sand becomes activated when combined with water, and needs to be applied as a dry polymeric sand to dry surfaces.

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50 lb. bag 50 lb. 56 2800 lb. Pallet

**Product production varies by plant. Please contact your salesperson for product availability in your location**

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Frequently Asked Questions

What is Weed-Blocker Paver Locking Sand?
Nurserymen’s Preferred Weed-Blocker Paver Locking Sand is a specially-formulated, polymer-modified joint sand used to lock together the units of pavement systems including segmental concrete pavers, clay pavers, and natural stone. Weed-Blocker is also used for filling gaps between concrete slabs or segmental retaining wall units.  Weed-Blocker locks pavers in place while resisting the growth of weeds, insect infestation, and sand erosion due to rain, wind, aggressive cleaning, tire action, and freeze-thaw movement.

How does Weed-Blocker work?
Weed-Blocker Paver Locking Sand is installed by sweeping the dry Weed-Blocker sand into the joints of pavers or stone.  Once in place, the area should be sprayed by a light wide spray of water which will activate the polymeric latex additive to hold the sand in place. 
 
Does Weed-Blocker still allow water drainage?
Yes, however it is very important to have a good drainage bed under the pavers for best performance of Weed-Blocker Paver Locking Sand.  A wet joint must be able to dry out in order for the product to perform as designed.  If your patio/walkway is   continuously exposed to a sprinkler or water source that keeps the joints moist, the joint will remain soft until it has the ability to fully dry out.

Can I use Weed-Blocker for the base or bedding sand?
No, a 1-2” layer of coarse bedding sand is recommended (ASTM C33) for the base material. Nurserymen’s Preferred Paver Base is ideal for forming the base for brick, pavers, and natural stone.

Will Weed-Blocker prevent weeds and insects?
Weed-Blocker Paver Locking Sand will restrict and resist growth of weeds and insect infestation. It performs best when it fills the joint completely to the full depth of the pavers. We can’t guarantee weeds won’t grow, but it will help considerably.

What joint widths should I use?
Weed-Blocker Paver Locking Sand is designed for a ¼” joint width, but has been used in wider joint applications up to ½”.

Can I use Weed-Blocker with flagstone or other irregular-shaped natural stones?
It can be used with the wider joints in flagstone or other irregular-shaped natural stones, but is prone to washing out of those joints more easily. Much will depend upon the drainage patterns. A good drainage bed below the pavers will help prevent the joints from eroding.

Can I use Weed-Blocker with clay brick pavers?
Yes, it is recommended to apply the product working in small areas at one time to reduce the amount of fine particles that get trapped in the pores of the surface of the brick. Fines that get trapped in the surface can leave a white film after wetting the  material.  A leaf blower on a low setting works well to remove the fines from the pores of the brick surface. If a white film becomes visible on the brick surface, you may try a light-steam pressure washer on the brick to remove the film.

Do I have to do any special preparation before installing the Weed-Blocker Paver Locking Sand?
Always clean the surface and depth by blowing or sweeping the pavers prior to spreading the Weed-Blocker. Do not apply this product in cool weather, under 50°F (10°C). Paver surface must be completely dry when applying Weed-Blocker and no rain in the forecast for at least 12 hours after application.

My pavers are wet, can I still apply Weed-Blocker?
No, moisture should not be present on the surface prior to applying Weed-Blocker Paver Locking Sand.  Any moisture could lead to early activation of the polymer and result in staining of the paver surface.

The bags of Weed-Blocker got wet before I got to use the product, is it still usable?
The Weed-Blocker Paver Locking Sand polymer is activated with water. Once wet, the polymer will “ball-up” product in the bag which would make it unusable. It is recommended you protect the bags from rain or moisture.

How do I make sure Weed-Blocker Paver Locking Sand has filled each joint?
Filling often requires two applications. Start by dividing the area into sections of about 200 sq. ft. Spread the Weed-Blocker over the surface of the first section then sweep into joints with a broom. Fill the joints up to 1/8” from the top. If the paver design has a beveled edge, do not fill the beveled section. If possible, run a powered plate compactor or vibratory compactor over the pavers once the joints have been filled. This vibration process will cause the sand to drop into the joints. Refill the joints by sweeping in a different direction perpendicular to the first, and repeat the compacting process. Use a leaf blower at low speed to blow  excess dust from the top of the pavers. It is very important to remove all dust from the surface prior to wetting down to prevent staining from the latex polymer in Weed-Blocker.

How much water should I use to spray down the surface after installation of Weed-Blocker Paver Locking Sand?
Apply a light, wide spray of water to the surface of the pavers and allow the joints to collect and soak up the water to full depth. Hard or narrow sprays of water could knock loose Weed-Blocker from the joints or cause the polymer to run off and prevent the sand from hardening. Using a low-pressure sprayer, evenly moisten the joints with a light spray in three applications at 10-minute intervals. Do not over-spray or flood the surface of your application. Spray in an upward direction in order for the water to fall lightly on the complete surface without displacing Weed-Blocker Paver Locking Sand from the joints. Do not allow water to splash Weed-Blocker onto the pavers. This wetting process should be done without interruption. Do not allow too much time to elapse.  If the surface of the joint sets and prevents water from reaching the bottom of the joint, the Weed-Blocker Paver Locking Sand can eventually fail.

How long does it take to set-up?
Allow a drying time of 4-6 hours before light traffic and 18-24 hours before heavy traffic depending upon temperature,
humidity, wind, and thickness of the joints.  Complete curing takes 30 days.

The Weed-Blocker don’t seem to be hardening, is there anything I can do?
The hardening is dependent on its ability to thoroughly dry out.  Excess water, rain, high humidity, or cool temperatures may slow the hardening process. Porous pavers that hold water longer or wider joints may take longer to harden. If your patio or walkway is continuously exposed to a sprinkler or water source that keeps the joints moist, the joint will remain soft until it has the ability to fully dry out. Weed-Blocker should be thumbprint hard before using the surface. It is not a cement product and will not harden like a cement-based grout. (Weed Blocker does not contain cement, nor should it be added). It will soften when it is wet & firms up when it dries. To increase the hardness and stability of the Weed-Blocker, a topping layer of Akona® Bonding Additive can be carefully applied to the surface of the sand (being careful to not apply to the pavers).  An inexpensive “turkey baster” can be used to apply the Bonding Additive full strength to the joints only, letting it soak into the joints.  Another option for increasing the hardness is to apply Nurserymen’s Preferred Landscape Loc Mulch & Rock Bond to the joints.  This takes 24-48 hours to dry and should not be disturbed until it is cured (no longer “tacky”).

The surface of my pavers were not completely clean before it got wet, what can I do?
When this happens, a white residue or latex film will often harden on the surface of the pavers. It is always best to try any removal method first in an inconspicuous area, and always rinse well after application.  Wet the pavers down with hot water and scrub with a wire brush. If film persists, wet pavers and apply a cleaning solution of TSP (tri-sodium phosphate) to the pavers. Scrub the pavers with a soft brush broom, then rinse thoroughly with clean water to remove the cleaner from the paver surface.

Can I seal my pavers after using Weed-Blocker Paver Locking Sand?
Yes, sealers can be applied over the Weed-Blocker Paver Locking Sand, always check with the paver manufacturer for sealer compatibility, recommendations and application instructions.

Are there different colors of Weed-Blocker Paver Locking Sand?
No, Weed-Blocker is not colored so it is available only in the color of natural sand.

Why choose Weed-Blocker Paver Locking Sand, can’t I get the same results with plain sand?
The polymer enriched Weed-Blocker has several advantages over plain sand: ants and insects will find it much harder to get through and into homes, weeds are deterred from growing through joints, the polymer helps keep the sand from washing out of  joints, and the overall joint strength is increased.

How should I store unused bags for later use?
Keep unused sand in tightly closed containers to protect from moisture. Does not require freeze protection.

What is the coverage for a bag of Weed-Blocker Paver Locking Sand?
The typical yield of one 50 lb. (22.7 kg.) bag is approximately 50-75 sq. ft. for a thin joint (clay paver brick) or approximately 20-35 sq. ft. for a wide joint (concrete paver).  Coverage estimates depend on various sizes of pavers or slabs and the size of the joint gap.

 

 

 

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