Insulating Hot Tub & Spa Cover FAQs

Q.  What is the importance of a gusseted skirt?

A.  One piece continuous skirts, which are easier to manufacture, have many inherent problems as compared to skirts that are gusseted (also called “slits”). Gusseted skirts not only hang much straighter, but also have less of a tendency to bunch-up under the cover when putting it on your spa. If the skirt folds under the cover it prevents a proper seal between the cover and spa, greatly reducing the covers insulating ability.

More importantly though, 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 excessive heat to escape, preventing heat damage from occurring.

Q.  Is heat sealing the inner wrapping important?

A.  The most common cause of spa cover failure is due to the foam cores absorbing moisture. Besides the moisture causing the cover to gain excessive weight, the saturation also greatly reduces the insulating ability of the cover.

One of the most important features of an insulating is the vapor barrier surrounding the foam. Not only is the type of material and it’s thickness important, but how it’s sealed is also important.

The simplest way to seal the foam is to simply wrap it in plastic sheeting and tape it closed. Unfortunately the tape will fail rather quickly thereby allowing moisture to penetrate into the foam. The preferred method for sealing the plastic sheeting is to properly heat seal it.

Special care must be taken when heat sealing, otherwise failure can occur prematurely. Just the right temperature must be applied to the plastic sheeting to achieve a proper seal.  Too hot and it will become brittle and crack open, too cool and it wont remain sealed. The ideal temperature will literally “weld” the polyethylene together.

Single-extruded, polyethylene sheeting has proven to be the best type of plastic to use for sealing the foam. Our machinery used for heat sealing is thermostatically controlled to maintain exact temperature tolerances.

We also use a very heavy, 6 mil polyethylene and seal it extra wide, to assure years of performance. One of the options we offer is to double wrap the foam core with the polyethylene sheeting, which further extends to covers lifespan.

Q.  Why don’t you have a grommet in the drain hole on the bottom of the cover?

A.  All spa covers must have a drain hole on the underside. This is too allow moisture and condensed water vapor to drain out of the cover. Due to the properties of the two materials we use for the underside, scrim and Reflex´ Energy Shield, they do not require anything to strengthen this hole or prevent the fabric from fraying. All a grommet would do is cause scratches in the spa as the cover is slid off and on.

Q.  What are the ASTM standards for a spa cover and why are they important?

A.  ASTM developed standards which include a category intended to protect children five years of age and under. ASTM Standard F1346-91 for spa covers includes specific performance tests and labeling requirements. Covers must be able to pass certain tests.

The first is Static Load. “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. In the case of a spa with a width or diameter not greater than 8′ the cover shall withstand the weight of 275 pounds”.

Second is Perimeter Deflection. “The covers shall be designed in such a way that when tested, deflection of the cover does not allow the test object to pass between the cover and the side of the spa, or to gain access to the water”. Additionally, testing for surface drainage is conducted to see if a dangerous amount of rain 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 proper warnings (as described by the Standard) and identify the product as a safety cover.

Q.  How long should I expect a spa cover to last?

A.  The life-span of a spa cover is dependent upon many different things. How much direct sunlight it gets, how well it’s cared for or abused, how extreme weather conditions are and how the chemicals in the spa are dealt with all have an effect on life-span. Generally though, if reasonably cared for a spa cover should last five to eight years.

Q.  What can I do to extend the life of my spa cover?

A.  Although very durable, a small amount of general care and maintenance can help extend the life of any spa cover.

• Do not over sanitize the water, and remove the cover when shocking. This is the most important thing. As excessive sanitizers evaporate, they can actually deteriorate many of the plastic materials a spa cover is constructed from.
• Periodically cleaning, treating and protecting the outer vinyl from the elements is the most important thing. 303 Protectant is the best thing for treating and protecting the cover from sun damage. Stay away from any petroleum based products that claim to condition vinyl. They actually do much more harm than good.
• Remove excessive snow to prevent the cover from sagging and possibly breaking.
• Never sit of stand on a spa cover.

Q.  How important is the warranty?

A.  As with any product, a comprehensive warranty is important. It’s important however, to look closely at, and understand the warranty. Warranties are frequently used as a marketing tool and can be very deceptive. While the warranty may state an extremely long time frame, the exclusions can make it virtually worthless.

Some retailers are adding an extremely long extended warranty, to the actual manufacturers warranty, as a marketing ploy. It should be interesting to see if they’re still in business (or have any happy customers) towards the end of this time frame.

Most warranties exclude damages caused by animals, fire, vandalism, excessive chemicals, improper installation, excessive weight load, acts of God and possibly more. Almost certainly, they also have an exclusion for “normal wear and tear”. What exactly is “normal wear and tear”, and who makes the determination on this?

The most important exclusion in all spa cover warranties is “shipping and handling”. The customer is ALWAYS responsible for this, and the cover has to be shipped back to the manufacturer and then again back to you.

Unless you can personally deliver the cover to the manufacturer, almost certainly the cost of shipping will be MORE than the cost of a brand new cover.

Prorated warranties are some of the most deceptive! It makes it look like the warranty has an even longer time frame, but now you’re paying not only for the shipping costs (in both directions, which can be more than the cost of a new cover), but also a percentage of the retail cost.

We have been in the manufacturing business since 1976, and though it’s rare, what few warranty problems we’ve seen, have never occurred after the first year! In fact, almost all have occurred within the first month.

Since we started double stitching every aspect of our spa covers, we have never had a warranty problem. While it is stated in our warranty that the cover must be returned to us for repair, we have never required the actual return of an entire cover at the customers expense for repair.

Q.  How is the R value of a cover determined?

This is an interesting question, that even we have had to wonder about sometimes. We’ve seen different retailers offering the same exact spa cover, yet the R-value “claimed” can vary by as much as 30%.

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 DensityR-Value/Insulation

The average spa cover cores, tapered 4″ to 2″, made of 1 pound density foam, have a total R-value of R-10.74 (calculated by averaging the thickness). Going to a 2 pound foam increases the R-value to R-13.05.

Additionally, some R-value can be added for the vinyl and poly wrap that seals the foam cores. But only about R-2. The R-value of a 1 pound density spa cover only calculates to, at most, R-13 (2 pound = R-15).

Q.  Can I order my spa cover from the make and model of my spa?

A.  Preferably not. Unlike cars, spa manufacturers are constantly modifying the spas. Sometimes twice a year!!!! Your measured dimensions are the most accurate and ensure a proper fit.

There are a number of reasons we prefer your actual measurements over our measurements on file:

1. Your spa may have warped slightly out of shape over time.
2. Manufacturers may have supplied us with fictitious measurements.
3. You may want a cover different from the original.
4. Your year or model may actually differ from what you believe it is.
5. We have a typo, or are simply wrong.

There are some exceptions to this. For spas in which the sides are bowed out and not straight, we most likely have a template. We also are working at acquiring templates for spas that have raised speakers in the corners that require “pockets” in the cover to properly cover them.

For these types of spa cover, please call us to check if we have the template and to place an order. We’ll need you to tell us the exact brand and model of your spa, and the year of production.

Q.  How long till I receive my cover after it’s ordered?

Please note due to Covid-19 lead time has been extended 12-14 weeks

A.  Depending upon your location, typical delivery time is 4 to 6 weeks after time of order. During busy times such as holidays shipping times may be slightly longer. Usually most covers will be manufactured and shipped within  4 weeks.

Q.  Do you keep covers in stock to order from?

A.  There are literally thousands of different shapes and sizes of spas and hot tubs in existence today, and with all of the manufacturing options we offer, cost and storage space make stocking covers impossible.

The one exception is some round sizes which are only available for in store pick up, please call to check for availability.

Q.  Can I just replace the foam in my existing cover?

A. No, over time the sun shrinks the outer vinyl covering slightly compressing the foam. A cover can actually shrink up to 1/2″ over it’s life.

Though a new foam core may seem reasonably priced, when you add in shipping both ways, it can cost almost as much as a whole NEW cover for just a single foam core.

Q. Can I replace only the outer covering on my existing cover?

A.  Just like trying to replace the foam cores, replacing just the vinyl outer covering usually isn’t cost effective. Our entire process for making spa covers, including patterns, cutting the vinyl and other fabrics, and cutting the foam cores, is completely computerized. The additional work involved to make a proper fitting vinyl covering could cost as much or more than a complete new spa cover. Although we can replace vinyl jackets we do not warranty it and we will only do this for Roberts Hot Tub Covers that were purchased from us directly.

Q.  What causes the underside of some covers to sag and droop into the water?

A.  Besides the obvious reason of a loosely fitted vinyl covering, the frequent cause of sagging is excessive air inside the polyethylene that seals the foam cores. Manufactured at cool temperatures, once on your spa the additional heat of the water will cause any trapped air in a cover to expand. It’s important (though difficult) to vacuum out any air that might be trapped during the process of sealing the foam cores in the polyethylene.

Q.  Why do some spa covers get so heavy as they get older?

A.  The foam a cover’s cores are made of is called Expanded Polystyrene and is made of small beads that are expanded with steam. Once expanded they are dried and then “attached together” simply by compressing them.

The more pressure they are compressed under, the high the density of the foam. The individual “beads” are waterproof! HOWEVER, water can saturate between the beads.
To reduce water absorption, the foam cores are “sealed” in polyethylene.

The most obvious cause of water absorption would be a small hole punctured through the cover. Even the smallest hole will allow a large amount of water to enter the foam over time.

The most common cause of water absorption is the “natural degradation of the polyethylene”. Over time, chlorine, bromine, non-chlorine shock and ozone will break down the polyethylene causing it to become porous.

The thicker the polyethylene (we use a 6 mil thick polyethylene), the longer it will resist this chemical degradation.  At some point however, it will become porous enough to allow evaporation and steam to penetrate through it. It WILL NOT be porous enough to allow the steam that has condensed back into water to drip back out.
Since eliminating all the chemicals isn’t possible (and still have a safe spa) the best preventative measure is a floating blanket. The blanket will greatly reduce both chemical off gassing, and more importantly evaporation.

It’s also important to completely remove the cover for a minimum of 20 minutes when shocking the water. This will allow the off-gassing chemicals to freely escape without penetrating into the cover itself.

Q.  Why do some covers use a welt cording?

A.  Welt cording is a feature that is typically used to “straighten” out crookedly sewn seams. The down side is that it gives dirt and mold a place to attach, and gives an extra ‘ridge’ to get hung or torn when handling the cover. We prefer to simply work a little harder and sew straight seams.