Must-do Steps for The Perfect Polyurea Pond

Polyurea is a two-part system delivered to the surface to be coated at approximately 200 degrees Fahrenheit and 2,000 psi by a specialized set of pumping equipment, heated hoses, and a spray gun. The two parts are heated and metered together by the pumping system, reaching the spray gun through heated hoses that can be several hundred feet in length.

Polyurea allows waterproofing of shapes like islands and steps that cannot be accomplished with liner. There are many polyurea formulas on the market for use in different situations and applications such as truck bed liners, roofing, decking, blast protection and armor plating, waterproofing, water containment, structural protection, and more. Many of these formulas have plasticizers that provide specific chemistry for a particular application. The formulas used for water containment are generally pure polyurea formulas with no plasticizers.

The beauty of using polyurea in pond construction is that it can be applied to virtually any shape or structure within reason, without any wrinkles or folds, and has approximately 400 percent elasticity. It can support tons of boulders without a puncture, and roots can't grow through it.

First, an underlayment is laid down first with the polyurea applied over it. Polyurea is also a perfect surface coating when cold joints between different concrete sections come together or when other structural materials such as piers or islands are in play. Indoor water features and features that come close to or incorporate the foundation of a building are prime uses. 

Polyurea is not glued! It has a "Band-Aid stick" to most surfaces and must be mechanically clamped to all penetrations, just as you would when using an EPDM liner. Pond-type skimmers, bottom drains, mid-water drains, and returns are all produced with clamping flange faces for liner. These are perfect for polyurea. Top edges can overlap and be captured by the top cap or stone, just as you would with liner. Edge treatments can be accomplished with a ledge around the top, just as you would a plant ledge with stacked rocks and boulders hiding and securing the edge.

Almost nothing sticks to polyurea. In installations where tile or vertical stone needs to be applied up the face of a surface or wall, stainless steel lath is fused onto the face to create a grid surface for the mortar to bond to.

Designing for Polyurea

Water and plants put the finishing touches on the island and waterfall. When considering polyurea, think, and design around what the technician needs to accomplish your goal. Construct in a "polyurea-friendly" manner. Corners should be radiused and not left as a sharp, 90-degree shape. It can be difficult to shoot into sharp corners, so even a slight radius of a half-inch is an improvement. Penetrations should be 10 to 12 inches away from corners, floors, or other formations to allow room for the spray gun assembly to be maneuvered. Columns and constructions should be at least 18 inches apart, and shallow troughs should be at least 18 inches wide for clearance. If a deep trough is created, it needs to be even wider so the technician can manipulate the equipment properly.

Polyurea is usually applied in several passes to achieve a thickness of approximately 80 mils. The spray gun needs to shoot at 90 degrees to the surface, spraying "head-on" and not an angle, to get an even coat. Spraying at an angle can cause runs, drips, and an uneven coating.

Concrete Prep

When applying polyurea over cement, the surface should have a "sidewalk" finish. Trowel the concrete surface as smooth as possible or parge the surface afterward to fill all the holes, gaps, and imperfections. Polyurea will look like the surface it is applied to, so make it look nice, just as you would "Bondo" the bodywork on a car before painting. Use a product that will become very hard and not powdery or weak when applied thin. Some parge coatings can have a bad chemical reaction with polyurea and pinhole, causing an immense amount of extra time to deal with. 

Your penetrations of choice's flanged surfaces will have several screw holes that you will need to find later to attach the clamp ring. Place a finish nail in one or two holes, leaving the others open. Filling all the holes with nails makes removal and preparation for the ring difficult because polyurea is tough and difficult to cut. Cutting just one or two nails out with a razor knife is easier, and once the first couple of screws are in place, the other holes are indexed through the holes in the clamp ring. The screws will go right through the poly and into the holes in the flange easily. If the skimmer face is supplied with nuts and bolts or machine screws, place a pair of screws in for indexing and cover the other holes with tape or paper dots. Install the first two and mark the other holes to be cut out afterward to connect the faceplate.

Communicate for Best Results

Preparing for polyurea means creating a project that the applicator can coat without a great deal of trouble. You are less likely to be charged for extra prep time by the polyurea technician if you do your job correctly. Make sure you allow for the prep time in your bid. On gunite or shotcrete ponds, let the crew know ahead of time what you expect from them. They are used to shooting around protruding piping that gets cut off later by the pool plaster crew. They will assume you want a rough surface for a plaster coat unless you specify otherwise. Ask if they can have a couple of cement finishers on hand to trowel the surface as smooth as they can and be prepared to pay for that. Otherwise, you will be parging the whole surface yourself after leaving to get the finished surface smooth enough for polyurea. This will be expensive and time-consuming. No matter how nice they make the surface, there will always be some prep to do around the penetrations and some nitpicking of tiny imperfections.

Once finished, the project will be waterproofed for some time, far longer than any other coating currently available. After you've experienced polyurea, you'll begin finding projects to use it on and expand the way you design.

If you would like to contact a Polyurea technician, we recommend calling or messaging ArmorThane via their website. They have been around for over 30 years, have technicians all over the world and specialize in industrial projects.