GFTK VDW 520 Xtreme Gravel Lock:


Enhance the beauty and durability of your outdoor spaces with the Xtreme Gravel Lock! The VDW 520 Xtreme Gravel Lock is a 2-component epoxy to be mixed with any clean aggregate to provide solutions for pathways, wide paver joints, tree pits, and more.

The following are a few specific details about the product:

  • Highly water-permeable
  • Suitable for extra-wide joints
  • Can be designed to accommodate up to light vehicular traffic loads
  • Pressure washer friendly
  • High UV resistance
  • Very high resistance to yellowing
  • Suitable for clean aggregates 1/16″ to 1″ in diameter
  • Suitable for glass chippings
  • Suitable for damp aggregates

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SKU: VDW 520 Categories: , , Brand:


Pressure washer friendly

Pressure washer Friendly

Easily Cleanable!
Epoxy Mortar is known for its exceptional strength and durability. It forms a robust and resilient bond between tiles, providing superior resistance to cracking, staining, and other forms of damage. With this gravel lock, your project can last the test of time!


Highly Water – permeable

Epoxy mortar is an environmentally friendly choice for tile installations. It is made with eco-friendly materials that reduce its impact on the environment. This allows water to pass through. This is important in freeze/thaw climates where durability is normally affected.

Resistant to yellowing

Very High Resistance to yellowing

It can withstand anything from heavy foot traffic and moisture to UV exposure and chemicals. This makes it ideal for high-traffic areas and outdoor applications. With this gravel lock, your project will stay beautiful for years to come!

High UV Resistance

High UV Resistance

Included in its strengths is that the epoxy has the ability to avoid degradation caused by the absorption of UV radiation. This will allow your project to stand the test of time for much longer. Especially while being in consistent sunshine.

Technical Data

Application Time

Approx. 30 minutes at 20°C | 68°F* application temp.

* Quick hardening at higher temperatures and slow hardening at lower temperatures.

Minimum Depth Requirements

1.5” for aggregates less than 1/2” diameter
For aggregates greater than 1/2” in diameter: depth must equal min. 3x avg. Diameter.
For vehicular traffic: The product must be laid on a permeable concrete or mortar bed (we recommend PHNA Xtreme Bedding Compound / VDW 480)

Water Permeability

Very High

Application Temperature

2-26°C | 37-80°F (Do not lay onto frozen ground.)

Mixing Ratios

The contents of one unit (5 kg) can bind a maximum of about 240 lbs. of aggregate (~160 lbs. glass chippings)
(Both bottles of A & B components have 1/4 delineation markings to accommodate mixing in smaller batches)

Storage Life

12 months, dry, and in an original sealed container. Do
not store at temperatures above 20°C / 68°F

Installation Instructions for GFTK VDW 520 Xtreme Gravel Lock

1. Construction Site Requirements

For pedestrian areas:

  • A stable and well-compacted gravel/sandbedding layer.
  • The depth of the PHNA Xtreme Gravel Lock should be a minimum of 1.5” after compaction and finishing.

For vehicular traffic:

  • The product must be laid on a permeable concrete or mortar bed – we recommend the PHNA Xtreme Trass Bedding Compound (vdw 480).
  • All elements must be correctly designed and installed for the anticipated traffic loads and in accordance with ASTM. The Xtreme Gravel Lock cannot be used to compensate for any settlement of the substructure.

2. Preparation

  • Clean the base material and any joint sides to ensure no contaminants or uncompacted materials are present.
  • Mask any adjacent areas not to be jointed to prevent any spots or staining from the epoxy.
  • Prior to Installation, we recommend a test area be prepared, particularly with any sensitive materials.

Material Preparation:

  • Any dirty or dusty aggregates should be washed thoroughly and dried prior to mixing to avoid discoloration and/or loss of strength.
  • Aggregate may be damp but cannot be wet.

3. Mixing

Tools Needed:

  • Heavy-duty paddle/drill mixer or suitable gravity mixer, large mixing tub, shovel, screeding tolls, and trowels.


  • Add the appropriate amount of aggregate into the mixing tub or gravity mixer.
  • Followed by the appropriate amount of both A & B components of the Xtreme Gravel Lock.
    • (The 5kg units of Xtreme Gravel Lock will have 1/4 markings on each bottle, each 1/4 to be mixed with a maximum of 60 lbs. aggregate.)
  • Mix for 5 minutes until homogeneous.

4. Application

  • Apply the freshly mixed material onto the prepared substrate.
  • Spread and level off with appropriate screeding tools or a trowel, then compact and smooth the surface with a trowel.
  • Material may get sticky and more difficult to work with after 30 minutes or in higher temperatures.

5. Important Instruction

  • Remain off the freshly applied areas and protect them from heavy rain for a period of min. 24 hours. Then the areas can be walked over carefully.
    • In general, a strength test should be carried out before final clearance of the area after 7 days.
  • The practice has shown that there are minerals for which the epoxy used can produce special effects such as darkening.
    • Over time, this weathers off, and the mineral substance regains its natural color.
  • In covered areas, the weathering process takes longer.
  • With bright white minerals, a slightly yellowish color change may occur.
    • Color differences may occur until curing is complete, especially with strongly varying UV radiation.
    • These phenomena result from the contact between Xtreme Gravel Lock epoxy and mineral aggregate and are not a design defect.
  • The gloss effect remaining after application will degrade over time from exposure to natural UV light.
  • Despite careful processing, marginal detachment of individual grains cannot be ruled out.

Additional information

Weight 12 lbs

Epoxy Only, Earthtone, Charcoal

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