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A full 6" to 4" thick tapered foam!
Roberts Extreme Spa Covers are some of the thickest, most insulating spa covers made. A full 6" thick foam core provides not only additional insulation value, but added strength as well.

Roberts Extreme Spa Covers foam core is the "back bone" of every spa cover. Not only is it the main insulating factor, it also provides a majority of the strength needed for years of use. One of the important features of our foam is that it's a virgin foam, rather than recycled. While both may have the same insulating value, recycled foam doesn't have nearly the strength as the virgin foam we use.

The foam core of the Roberts Deluxe Spa Cover is a 1.5 pound density, metal reinforced, EPS (expanded polystyrene) foam , tapered from 4" to 2". The foam core of the Roberts Extreme Spa Cover is a 1 pound density, metal reinforced, EPS (expanded polystyrene) foam , tapered from 6" to 4".

Please note, these measurements are the true measurement of the foam itself. It is not a nominal measurement, nor does it include the thickness of the vinyl or vapor wrap (you'd be surprised how many others don't use a "true" measurement, and add in thickness of the other materials used). The taper is necessary to allow accumulated water to easily run off. Many older, and some cheap covers are made of a flat foam which will allow water to puddle,causing the cover to sag, allowing more water to puddle, eventually breaking the cover.

Foam density refers to the weight of a cubic foot of foam. A 1.5 lb. density is generally the ideal for a 4" thick cover. It has excellent strength and insulating ability, yet is light enough to maneuver on and off your spa. Lesser densities are NOT advised for a cover of this thickness due to their lack of strength. With our 6" thick cover, a 1 pound density is more than enough. It provide almost 50% more insulation value over our 4" cover, is stronger, yet is the same weight. Higher foam densities have additional strength, but only slightly more insulating ability. One of the many options we offer is upgrading to a higher density foam if additional strength is needed.

High insulating R-value value!

With the standard 1 pound density foam cores, Roberts Extreme Spa Covers have a minimum R value of R-21. The optional 1-1/2 pound density foam achieves an even higher R-value!

The insulating core of almost all spa covers is EPS (Expanded Polystyrene). The insulating value of this product is very specific, and is listed in the table below. Please note, the R-value shown is for 1 inch of thickness.

Foam Density R-Value/in.

1.0 3.85

1.25 4.0

1.5 4.17

2.0 4.35

Remember, all EPS foam of equal density has the same R-value!

"What is the R-value of your cover"? While this is the most common question asked when comparing covers, the answer can be the most deceptive. The following, though rather lengthy, explains insulation and R-value. The short answer to the R-value of our covers though, is R-14½ with the Deluxe Spa Cover and R-21¼ with the Extreme Spa Cover.

R-value describes a material's resistance to the flow of heat. The higher the R-value, the slower heat will travel or conduct through a material. Better insulating materials tend to have better R-values.

Heat flows by three mechanisms: conduction, convection, and radiation;

Conduction is the molecule-to-molecule transfer of kinetic energy (one molecule becomes energized and, in turn, energizes adjacent molecules). A cast-iron skillet handle heats up because of conduction through the metal.

Convection is the transfer of heat by physically moving the molecules from one place to another. Hot air rises; heated water thermosiphons; forced-air heating systems work by moving hot air from one place to another.

Radiation is the transfer of heat through space via electromagnetic waves (radiant energy). A campfire can warm you even if there is wind between you and the fire, because radiation is not affected by air.

R-values by definition, only measures an insulation's ability to resist heat loss by CONDUCTION.

The above's relationship to spas is this; heat from the spa water rises by convection and radiation. As it rises it heats the underside of the cover, then moves through the cover by conduction. Increasing the covers R-value reduces, or slows the rate of conduction. There are also two ways to reduce the rate of convection, the first being a floating blanket, the second being our optional exclusive Reflex Energy Shield used for the covers underside material.

R-value is a term coined by the FTC in response to a need for a way to compare the relative effectiveness of various forms of insulation. R-values are measured by testing laboratories (ASTM), usually in something called a guarded hot box. As air within the test hot box is heated, convection takes place, causing the heat to rise. As the heat rises it warms the underside of the test object where upon conduction of the heat through the object begins. The R-value is the ability of the object (in this case the foam core of the spa cover) to slow this conduction. Heat flow through the object is calculated by keeping one side of the material at a constant temperature, say 90°F (32 °C), and measuring how much supplemental energy is required to keep the other side of the material at a different constant temperature, say 50°F (10°.C)--

Various industries are required to have their products R-value tested using ASTM standards under very exact testing perimeters. One of the parameters of this test is the temperature at which guarded hot box is heated to, AND the temperature the other side of the test material is kept at. Changing either of these temperatures will result in different R-value results. Once again, certain industries are required to use ASTM testing procedure and parameters. For these industries, when they list their products R-value (such as R-20) it's generally understood that the difference in temperatures of the testing procedure is 40 degrees. It's also acceptable to list another R-value AS LONG as the temperature difference is ALSO listed (i.e. R-40 @ 20º). Here's the relationship to spa covers. SPA COVERS ARE NOT IN AN INDUSTRY REQUIRED TO HAVE R-VALUES TESTED ACCORDING TO ASTM STANDARDS! When comparing the R-value of a hot tub or spa covers it's important to ask what temperature difference the R-value was calculated at. Our covers are insulation value, as per ASTM standards are R-14 (tested at the ASTM standard of 40º temperature difference).

Reinforcing metal C-channel!
The foam cores are further strengthened with a full 20 gauge, 2½" wide C-channel running the entire length of the cover.

Running the entire length of each piece of foam, along the hinge is a 2½" wide, 20 gauge galvanized steel C-channel support beam. This is the heaviest gauge (thickest) reinforcement beam used in the industry, others tend to be 22 to 26 gauge. Galvanized steel is used for it's increases strength over aluminum, and also because of it's greater resistance to chemicals (chlorine and bromine). C-channel is much stronger than lesser expensive T-bar others may use.

If the possibility of this C-channel rusting has been made a concern to you, it really shouldn't be. The only way for this C-channel to rust is if the vapor barrier surrounding the foam is broken. If this happens the foam core of a cover will absorb water (getting heavier and heavier) long before the C-channel loses any integrity.

6 mil vapor barrier!
The vapor barrier surrounding the foam is the most important aspect in protecting the cores from absorbing water. Not only is the vapor barrier of Roberts Extreme Spa Cover's the thickest, but the option of adding a second layer make it the most protective!

One of the most important features of an insulating cover is the vapor barrier surrounding the foam. The barrier used in Roberts Extreme Spa Covers is a 6 mil. single-extruded, polyethylene sheeting. This extra thick sheeting is then double heat sealed around the foam core. As an added feature the sheeting is vacuumed of air during the sealing process. This prevents the cover from "bloating" from any trapped air expanding, when the sun beats down on it.

One of the options offered on Roberts Extreme Spa Covers is to double wrap the foam core with a second layer polyethylene sheeting. This is something few other manufacturer offers and we highly recommend it due to the following; Covers have a small hole on the bottom side of the vinyl covering to allow any accumulated water and condensation to drain out. As much as this is an absolute necessity, it also allows evaporating chemicals to rise up into the covers interior (needless to say covers with an open mesh bottom are the worst). Over a long period of time these chemicals can start deteriorating the vapor barrier to a point where it becomes porous. The porosity then allows steam and evaporating water to penetrate into the foam insulating cores. One day science will probably develop a better vapor barrier (although those wanting to sell lots of covers may not use it), but until then doubling up the polyethylene sheeting can greatly extend the life of your cover.

Optional continuous hinge seal!
Rather than just "fingers" or "steam sealers" that seal the very ends on the hinge, Roberts Extreme Spa Covers have an optional insulating flap running the entire length of the hinge!

Roberts Extreme Spa Covers have an optional continuous insulated "hinge seal" to prevent heat from escaping from an area most people don't even think about. Most other covers have what are called "fingers" or "steam sealers" (fig. 1 below). These are two pads that are placed on the underside of the cover, at the ends, between the two halves to prevent steam and heat from escaping when the cover is installed on your spa. If you turn one of these covers upsidedown you'll actually see that they also push the two insulating halves apart (fig. 2), leaving as large as a one inch gap between the two halves. This is equal to having a hole the size of a basket ball in your cover, your INSULATING cover!

Figure 1

Figure 2

The optional continuous "hinge seal" also has two handles to make maneuvering the cover on and off the spa in tight areas easier.

seam-seal1.jpg (9593 bytes)

The heaviest and most durable vinyl!
With a weight of 30oz. (per lineal yard), the vinyl of Roberts Extreme Spa Covers is the heaviest available. It also exceeds the specifications of "Marine Grade Vinyl", and "Premium Grade Vinyl".
"Marine Grade Vinyl" was developed for the harsh climates of boating and the awning industry. To be classified as a marine grade, the vinyl has to meet certain requirements (whether these requirements are exceeded or not is another story). The vinyl used in Roberts Extreme Spa Covers exceed all specified requirements of both "Marine Grade Vinyl", and "Premium Grade Vinyl"!

The following are the specifications of the vinyl used in our covers (helpful for making any comparisons);
- UV Rating & Weather Resistance : 1500+ hours
- Stabilized Pigment Rating : 500 hours
- Weight : 30oz
- Thickness : .040
- Cold Crack Rating : -20°
- Abrasion Resistance : 200 Cycles
Unlike some covers where the vinyl cover is heat sealed together, another important feature of Roberts Extreme Spa Covers is that they are completely double sewn together with the highest quality thread. Heat sealed seams become very brittle in the hot sun and freezing cold.

The vinyl in Roberts Extreme Spa Covers, besides being the thickest in the industry, also has mildew inhibitors, UV stabilized coloring to prevent fading, increased resistance to chlorine and bromine and is available in 10 colors.

Continuous one-piece reinforced hinge!

Roberts Extreme Spa Covers solid one piece, multiple layered hinge is optionally reinforced with nylon webbing making it the strongest part of the cover!

With the current trend of cover lifting devises (which we highly believe in) the hinge is one of the most worked parts of a cover. The Roberts Extreme Spa Covers hinge is constructed of the same high quality vinyl as the rest of the outer cover. It is not simply two halves of the cover sewn together, but is a one piece hinge, double stitched into each half of the cover. There's also a unique hinge-seal on the underside of the cover to fully insulate this normally uninsulated area. One of the options available is additionally reinforcing the hinge by adding an extra layer consisting of the same 1-1/2" wide nylon webbing the handles are made from. This upgrade consists of a strip of nylon webbing running the entire length of the hinge! While other covers hinges are their weakest point, this nylon webbing reinforcement makes the Roberts Extreme Spa Covers hinge the best possible!

Large corrosion proof zippers!

The zippers are one of the lesser important parts of a cover. However if anyone ever steps on your cover causing the foam to bow you'll want to remove and turn over the inner foam core. For this reason Roberts Extreme Spa Covers use zippers designed to maintain their "zipping" ability for years. The large teeth (6mm) prevent debris from causing them to stick and they're rust and chemical corrosion proof. And of course they're double stitched for added strength.

Super strong reinforced tie-down straps!

With so many covers in areas of high winds, Roberts Extreme Spa Covers use exceptionally strong nylon webbing for the tie-downs. These are the strongest tie-downs possible.

Just like the handles, the tie-downs of Roberts Extreme Spa Covers are also made of exceptionally strong nylon webbing . Each cover comes standard with four tie-downs equipped with locking child resistant safety latches. To assure the integrity and prevent the straps from ripping out (perhaps from high winds), the straps are sewn into the cover in four places, including the skirt. This makes them virtually tear-proof.

Besides aiding in keeping out unwanted visitors, the tie-downs, when properly used help to prevent strong winds from blowing off the cover. There is also the option of additional tie-downs.

The "locking latches" are molded after the quick release buckles found on sports equipment and have been specifically designed for spas! Each NMF Fastener may be locked down individually. They are quickly installed with three stainless steel screws (provided).

Gusseted, double stitched skirt!

Expertly designed to protect the outer edge of your spa, the skirt of Roberts Extreme Spa Covers are also strong enough to lift the cover!

The skirt of a cover is another of the many important parts. It needs to properly protect the lip of your spa from the damaging rays of the sun, and be strong enough to use for lifting your cover. Roberts Extreme Spa Covers skirts are double stitched into the cover for strength, and gusseted to provide the best protection! One piece continuous skirts, which are easier to manufacture, have many inherent problems as compared to skirts that are gusseted (also called "slited"). Gusseted skirts hang much straighter and have much less tendency to bunch-up under the cover, preventing a proper seal between the cover and the spa. As the sun beats down on a cover, extreme heat can build up between the skirt and the outer lip of the spa. This intense heat can actually damage the outer lip of the spa. A gusseted skirt allows this heat to escape, preventing heat damage from occurring. The skirts are double sewn into the cover for extra strength and strong enough to lift even the heaviest of covers.

Heavy duty handles!

Unlike the handles on many covers which tend to be a great weak point, Roberts Extreme Spa Covers handles have been designed and engineered to be one of the strongest! Handles are great when the cover is new, but over a long period of time most covers eventually get a bit heavier. Cover handles, having such a small attachment area can be easily torn off, sometimes tearing the cover. Our cover's handles are made of extremely strong, 1-1/2" wide nylon webbing. Additional stitching, and internal reinforcing make them some of the strongest available. One of the many options offered, is to have the nylon handles vinyl covered. It should also be noted that you can also lift this cover by the skirts. Our skirts are reinforced and designed for lifting the cover.

Standard nylon webbing handle
Optional vinyl covered handle.

On the underside of the cover there are two additional handles attached to the continuous "hinge seal". These handles help in maneuvering the cover on and off the spa in tight areas.

Double laminated polyester scrim underside.

12oz double laminated, tight mesh reinforced, chemical and ozone resistant scrim underside. Optional Reflex Energy Shield adds even more insulating ability!

The underside material of the cover that faces the spa's water takes the most abuse. It's also the first line of defense in preventing chemical damage and moisture infiltration, and must be durable enough to withstand the constant dragging from removing the cover from the spa. Roberts Extreme Spa Covers use a12oz double laminated, tight mesh reinforced, chemical and ozone resistant scrim. This material is so strong (it's constructed similarly to rip-stop- nylon) that it's used internally throughout the cover to reinforce the double stitching.

As an option, the scrim can be substituted with Reflex Energy Shield, a 12 oz scrim coated with a highly reflective, woven metallic material. One of the ways heat is lost is that it radiates out in waves (see above on R-value for a full explanation on insulation value and heat loss). The Reflex Energy Shield gives our spa cover a great advantages over other spa covers. The reflective nature of the Reflex Energy Shield yields a reflecting dish effect that bounces these heat waves back down into the water thereby increasing the cover's insulating ability.

Please note, excessive chemical use in the spa can lead to the woven metallic material "blistering" from the scrim. Excessive chemicals are the only thing to cause this, and blistering or bubbling is not covered under warranty. Covers with Reflex Energy Shield should be removed from the spa for a minimum of 20 minutes when shocking.

Moisture drains!

Specifically located to prevent water from accumulating inside the cover, and designed to not scratch the spa when the cover is removed.

Color matched thread!

The thread used in Roberts Extreme Spa Covers is a 93#, UV resistant, bonded, Dacron Polyester thread. Covers are completely double stitched and this thread will not mildew or rot, nor will sunlight degrade it over time.

With the entire cover being double stitched together, the thread is also an important aspect to consider (some cover manufacturers heat seal their vinyl together, but the seams tend to become very brittle in the hot sun and freezing cold).

The thread used in Roberts Extreme Spa Covers is a 93#, UV resistant, bonded, Dacron Polyester thread. The polyester part is what's important, unlike cotton thread (or cotton wound polyester) it won't rot out in a short period of time, and the UV resistance prevents any degradation form the sun. "Bonded" means that it's actually water tight and can't absorb mildew causing moisture. The 93# is the weight of the thread and the entire Roberts Extreme Spa Cover is completely double stitched.

Ten colors!

Please note, colors may vary slightly from how they appear on your computer

Meets or exceeds ASTM F1346-91 standards!

ASTM (American Society of Testing: and Materials) has developed a standard for Pool & Spa Covers intended to protect children under the age of five. This Standard, ASTM F 1346-91, establishes three cover classifications:

Power Safety Covers, typically found on swimming pools.

Manual Safety Covers, such as the Roberts Extreme Spa Covers.

Other Covers, which do not serve as a barrier for children under the age of five and do not qualify as a safety cover.

While Roberts Extreme Spa Covers have been tested to not only meet, but exceed the "ASTM F1346-91 Manual Safety Cover Standard" (when used according to instructions), adult supervision is the only way to prevent accidents. Be sure to maintain constant eye contact with children whenever they are near or could get near any body of water.

The ASTM Standard includes specific performance tests and labeling requirements. Covers must be able to pass tests such as static load tests for weight support, perimeter deflection tests for entry or entrapment between the cover and the side of the spa, and surface drainage tests to see if a dangerous amount of water could collect on the cover's surface. There are also requirements to include labeling in consumer information and on the cover itself. Labeling must contain the proper warnings (as described by the Standard) and identify the product as a safety cover.

ASTM PERFORMANCE REQUIREMENTS:

Static Load: In the case of a spa with a width or diameter not greater than 8' the cover shall withstand the weight of 275 pounds. In the case of spas with a width or diameter greater than 8' from the periphery, the cover shall be able to hold a weight of 485 pounds to permit a rescue operation.
Perimeter Deflection: The covers shall be designed in such a way that when it is tested (installed according to directions), deflection of the cover does not allow the test object (sized to simulate a child's head) to pass between the cover and the side of the spa, or to gain access to the water.
Other Requirements: Special labeling, fastening (locking down), surface drainage and conformance on literature and notifications standards.

Four year warranty!

Roberts Extreme Spa Covers four year warranty is one of the most comprehensive warranties in the industry.


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