Winter safety covers
Once the outside temperature has reached a point where pool usage is low, and energy costs related to water maintenance becomes impractical, the annual winterization process begins. A tarp-type cover with water tubes/water bags was the standard when it came to covering most pools. However, tarp covers have their downsides, as they tend to be full of wrinkles, collect surface debris and stagnant water, and until the water in the pool freezes, they pose a major entrapment concern for children, pets, and wild animals.
With the growing scale of residential watershapes, it makes little sense to install an unattractive cover on a pool that was designed to be esthetically pleasing. A winter safety cover provides a clean, sleek, and attractive look to any backyard and is the most secure system for pool winterization. These covers can be manufactured to fit any pool type and/or shape and are available in a number of colours.
Mesh safety covers
These safety covers are constructed with a strong woven polypropylene mesh. All of these covers must conform to the standard performance specification set by the American Society for Testing and Materials (ASTM). Most manufacturers provide a 15-year pro-rated warranty with their covers, while some safety covers may even qualify for reductions in home liability insurance.
To install these cover systems, anchor points are drilled into the surface of the pool patio, raised wall, boulders, or water features. They can be fastened and anchored into most forms of decking, including concrete, interlocking pavers, natural stone, wood, composite materials, and lawn or garden bed areas. These anchors generally comprise a brass sleeve that is hammered into the drilled hole and have a screw-type fastener with a hex head to attach the steel springs, using tension to keep the cover tight and in place. Further, the springs allow the cover to flex as ice and snow accumulate, or to support the weight of a child, adult, or family pet. Upon opening the pool for the season, a technician will remove the cover springs from the anchors and screw in the fastener so it is flush with the deck.
As the mesh allows water, ice, and snow to penetrate, there is no need to pump accumulated winter precipitation off of the cover. This conserves water, which is required to re-fill the pool to operating level and makes the spring start-up procedure quicker and more efficient. That said, it should be expressed to clients that some fine surface debris will pass through the cover mesh, which will leave some sediment in the water upon start-up; however, this can be easily resolved with a quick pool vacuuming.
Solid safety covers
Solid safety covers share identical cover components and installation methods as mesh systems. The difference, however, is standing water cannot pass through the cover; nor can light, which aids in the prevention of algae growth. Due to the former, these covers require a sump pump or drainage holes positioned throughout the cover to allow water to drain freely.
Measuring
Manufacturers of mesh safety covers rely heavily on the accuracy of the measurements provided by the cover installer. Standard shapes such as a rectangle can be easily measured by providing the length and width of the pool. Freeform- or lagoon-shaped pools require the use of A-B point triangulation. This method requires the installer to establish a point from A to B followed by measurements at intervals of approximately 305 mm (12 in.) (or smaller) along the entire pool perimeter. Any obstruction within 305 mm (12 in.) of the pool’s edge should be noted so the manufacturer can make the correct cut-outs for the cover.
The greater the accuracy, the easier it becomes for the cover designer to scale out the drawing using computer-aided design (CAD) software. This allows the designer to accurately map out the entire layout of the pool with all its decking and potential obstructions. As much details as possible should be forwarded to the manufacturer (e.g. pool construction plans, project photographs from multiple angles, etc.). These methods enable the manufacturer to not only provide the installer with the safest and strongest anchoring points, but also an accurately fitted cover.
With the ever growing ingenuity of watershape designers and builders, and the addition of complicated water features, raised walls, zero-edge (perimeter overflow) and vanishing-edge designs, even greater accuracy is necessary when measuring for safety covers. Certain areas pertaining to the accurate fit and support of these covers also need to be taken into consideration. For instance, anchors may need to be fastened into wall surfaces or with steel cables to achieve the necessary strength to handle the required load. Therefore, any peripheral materials being drilled into need to be structurally sound. Projects using imported stone, glass tiles, or other foreign materials may not be suitable to support anchoring and should be assessed prior to cover selection.
As designers and builders in colder climates, it is important to explain to the homeowner the benefits and options that suit their particular project. Extending the usability, efficiency, and safety of a watershape should always be the end goal of any project. At the end of the day, a satisfied homeowner with a dream backyard is the added bonus.
Michael Willis is an aquatic designer and partner at Roger Willis Contracting Ltd., which specializes in unique, custom aquatic projects based in Ottawa, Ont. He works
in various fields—from project design to completion—and builds throughout eastern Ontario and the Caribbean. He is a member of the Master Pools Guild, Pool & Hot Tub Council of Canada (PHTCC), and Landscape Ontario Horticulture Trades Association. He can be reached via e-mail at michael@rogerwilliscontracting.com.
