What Makes a Strong Winter Pool Cover?

There are many types of solid swimming pool covers on the market today. This article will focus on solid polyethylene (poly) covers for above ground and inground pools. In this category of covers there are many weights, thicknesses, and qualities to choose from. There are two basic qualities that determines the relative strength of solid “poly” covers: inner scrim & outer coating.

Inner scrim – polyethylene solid covers are made up of a woven inner scrim sandwiched between a top and bottom layer of polyethylene coating. The inner scrim is made of woven polyethylene tapes. The individual tapes can be made with 100% pure polyethylene or combined with filler and recycled materials is much cheaper but weakens the strength of the inner scrim.

The strength of each woven tape is measured by the weight and thickness called “dernier”. Generally, the heavier and thicker a dernier tape, the stronger the tape. However, a heavy dernier tape will be weakened by using fillers or regrind material in its manufacture. The best/strongest winter covers have a scrim that is high dernier and is made from 100% pure polyethylene.

The inner scrim is responsible for the tear strength of the cover. Winter covers made of high dernier, and100% polyethylene are almost unrippable and will hold up to high winds and winter conditions much better than low dernier covers or ones loaded with fillers and regrind.

Beware of covers that display high weave counts like 12x12 & 14x14. This is referring to the number of woven tapes in the inner scrim per inch. The high thread count is an attempt to mislead the consumer and hide the low dernier and relative weakness of their covers. The strongest winter covers have high denier and 100% polyethylene without fillers or regrind. The strongest winter covers are made with the strongest scrims.

The scrims are coated with polyethylene on the top and bottom. The “poly” coating makes the cover waterproof. The bottom “poly” coating is black to help deter algae from growing and the top coating can be various colors depending on consumer preference. While the “poly” coating does little to enhance the strength of the cover, it does provide the cover with important protection from sunlight damage. The strongest winter covers are coated with poly coating that is loaded with UV (ultraviolet) inhibitors. This means these covers will remain strong and protective for many seasons. Sunlight can damage untreated polyethylene quickly! Inferior covers attempt to fool customers with thick “poly” coatings. While the cover feels thick, its poly cover lacks protective UV inhibitors and will break down quickly in sunlight.

Frostguard™ covers from Freetime Fun combine a high dernier inner scrim made of 100% pure polyethylene, that is coated with UV stabilizers to insure many years of pool protection. Our covers cost a little more, but they will last for years and years.