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Construction Tips: Using Waterfall Foam [Video]

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Ed Beaulieu from Aquascape shows us some best practices for using waterfall foam.  Waterfall foam is used to fill in the gaps between the rocks and boulders in your waterfall.

You want the water in your falls going over the rocks, not under them.  Without some type of sealant, the water will flow back behind and under the rocks and you’ll seem to loose a lot of your water flow.  A couple tips that Ed will show you in the video include:

  1. Start off with tight joints between the rocks to minimize the amount of foam you need to use.
  2. Use small stones and gravel to fill in the larger gaps between your rocks.
  3. You’ll have 30 minutes from when you crack open the waterfall foam to apply it.
  4. It will cure in about 20 minutes once it’s out of the can.
  5. Use an applicator gun!


Hi, this is ED Beaulieu with Aquascape bringing you construction tips from the field. Today, I want to talk to you about how to get the most out of your waterfall pump using the Aquascape Black Waterfall Foam.

Aquascape’s expandable black waterfall foam is a water sealant used to fill the gaps and voids between the rocks in your waterfall, while most of the flow in a dry-stacked waterfall will naturally be lost behind the stones, a properly foamed waterfall will keep the water flowing over the top, where you want it. Aquascape offers a family of black waterfall foam products to choose from. Our DIY foam is an easy-to-use, single use, disposable can for the beginner or do-it-yourselfer. Also sold as part of our installation kit, it’s convenient and economical for small water features or as a quick touch-up on a larger project.

Aquascape’s Pro-Foam is designed for professional pond builders. Equivalent to five DIY cans, the 24 ounce can of Pro-Foam works with an adjustable applicator gun that provides exact dispersion of foam for sealing waterfalls. The Pro-Foam gun is reusable from one project to the next and is sold in a convenient kit that includes a carrying case for storage and protection.

An economy model of our popular, professional foam gun is also available. This lower price foam gun provides an attractive price point, so even if you build one or two water features a year, you can still afford to add a foam gun to you pond-building tool kit.

The goal when building waterfalls is to have tight joints between the stones, leaving only small voids to be filled with waterfall foam. Start by filling the larger voids with a mixture of small stones and gravel. Prepare the DIY foam for use by threading on the applicator trigger and attaching the dispensing straw. Once the seal is broken, you will have roughly 30 minutes to use the entire can. Shake well and hold the can upside down to apply the DIY foam over the rock and gravel fill, understanding that the foam will expand once dispensed. Continue to foam between the waterfall framing rocks, along the stream edges, and anywhere else you feel that the water may be lost. Strategically place larger stones and gravel on top of the wet joints to help disguise it and allow roughly 20 minutes for curing. Once the shell of the DIY foam is cured enough to manipulate by hand, hide any excess foam by molding it down into the joints.

The use of an applicator gun makes all the difference when foaming a waterfall in front of a Biofalls filter. Once the waterfall is dry-stacked and any voids filled with gravel, shake the Pro-Foam and open the nozzle by turning the knob on the back of the gun. Insert the applicator and deep-foam the interior of the waterfall. Set the keystones into the wet foam and backfill the rest of the area with gravel. This will lock the stones in place while creating a watertight seal that forces the water over the rocks. Be sure to close the nozzle of the gun when finished to avoid any clogging. As a general rule, a can of foam should always remain on the gun with the nozzle closed, even if the can is empty. For long-term storage of the applicator without foam, a can of foam cleaner is included with the kit. To swap an empty foam can, simply close the nozzle and unthread the empty can. Thread on a new can of foam and reopen the nozzle to continue foaming where you left off. Let the foam set for a couple of minutes, while allowing it to expand into the voids and then dust the wet joints with rock dust or sand to help blend it into the surroundings. Allow 15 minutes for the foam to cure and you’re ready for water.

What a difference a little black waterfall foam makes. You can see how the foam actually diverts the water where you want it. That’s the beauty of using expanding black waterfall foam. I hope these tips will help you on your next waterfall project. We’ll see you next time.

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