How to Choose the Right Oversized Spa Cover

ChrisG December 20, 2025

An oversized spa cover is any cover larger than 96 inches in length or width.

Once a spa goes beyond standard cover dimensions, you need to plan the construction, panel layout, measuring process, and final fit more carefully.

At Spa Covers Etc., we build oversized spa covers with panels up to 120 inches wide. Length is much more flexible because we can add additional panels as needed.

As a result, we can build covers for very large spas, swim spas, built-in plaster spas, fiberglass spas, and unusual installations that cannot use a standard two-panel cover.

What Is Considered an Oversized Spa Cover?

For our covers, anything larger than 96 inches in either direction falls into the oversized category.

Examples include:

A spa that is 108″ x 108″
A swim spa that is 90″ x 192″
A large built-in plaster spa
A wide fiberglass spa
An unusually shaped spa that requires multiple panels

We use Heavy Duty 2.0 lb foam for oversized covers because larger panels require additional strength.

Depending on the total size, we may build the cover in three pieces, four pieces, or with additional sections.

How Large Can an Oversized Spa Cover Be?

We can build oversized spa covers with panels up to 120 inches wide.

Length gives us more flexibility because we can add extra panels for very long spas and swim spas.

The final number of panels depends on:

Overall length
Overall width
Shape of the spa
Where the cover needs to fold
How the cover will be handled
How the spa is installed

In some cases, a three-piece layout works well. Larger spas may require four pieces or more.

We may also use a special center panel when the overall dimensions call for it.

Start With How the Spa Is Installed

Choosing the right oversized spa cover starts with understanding how the spa is installed.

For example, you do not measure a built-in plaster spa the same way you measure a raised fiberglass spa.

That difference becomes especially important with oversized covers because the cover must fit the installation as well as the spa itself.

Built-In Plaster Spas

For a built-in plaster or Gunite spa, the cover normally needs to rest securely on the surrounding coping.

Therefore, you should not make the cover only to the size of the water opening.

Instead, we look at the water span and determine how much extra coverage the cover needs so it can rest properly on the coping.

In many cases, this means adding approximately 3 to 4 inches per side, or 6 to 8 inches overall, beyond the water opening.

However, the exact amount depends on the coping, shape, surrounding deck, and where the cover can sit securely.

With oversized built-in spas, proper support on the coping matters just as much as the overall dimensions.

Raised Fiberglass Spas

A fiberglass spa may sit several inches above the deck.

In that situation, we can often build the cover to fit the spa shell itself and use a skirt to cover the exposed side of the spa.

The skirt hangs around the outside edge and gives the installation a cleaner finished appearance.

Because the cover fits the raised shell, it may not need to extend onto the deck at all.

Recessed Fiberglass Spas Require a Judgment Call

Recessed fiberglass spas can be more complicated.

When the spa shell sits close to deck level, more than one cover design may work.

For example:

Build the cover to fit the fiberglass spa itself and use little or no skirt
Make the cover larger so it rests on the surrounding deck
Adjust the size around raised controls, trim, or uneven deck areas
Use a combination of overlap and skirt depending on the installation

This is where experience matters.

Ultimately, the right choice depends on how the spa sits in the deck and where the cover will receive proper support.

Should the Cover Fit the Spa or Rest on the Deck?

There is no single answer for every oversized spa because each installation is different.

A built-in plaster spa usually needs a cover that rests on the coping.

By contrast, a raised fiberglass spa often works better with a cover that fits the shell and uses a skirt.

A recessed fiberglass spa may require more planning. In that case, we may need to decide whether the better solution is to:

Fit the spa closely
Make the cover larger
Let the cover rest on the deck
Use a skirt
Avoid a skirt entirely

The goal is to create a cover that has proper support, fits the installation, and remains practical to handle.

Panel Layout Matters

Large covers need sections that make sense for the size and shape of the spa.

A poorly planned panel layout can make the cover difficult to move or create awkward folding points.

When we choose the layout, we consider:

The total dimensions
Which direction the cover should fold
How the sections will be removed
Where handles are needed
Whether the cover will use a lifter
Whether walls, railings, landscaping, or structures limit access

For that reason, the largest possible panel is not always the most practical choice.

Unusual Shapes and Templates

Oversized spas are often more complicated than simple rectangles.

Common shapes include:

Rounded ends
Oval sections
Large radius
Cut corners
Angled sides
Free-form shapes

We can build some shapes from measurements alone.

More complicated shapes, however, may require a full-size template.

A template becomes especially important when small differences in shape could affect where the cover rests or how the sections line up.

Heavy Duty Construction Is Standard Over 96 Inches

We build all of our oversized spa covers over 96 inches with Heavy Duty 2.0 lb foam.

Larger panels need stronger construction than a standard spa cover.

In addition, the total span and number of panels affect the final design.

For oversized covers, the complete construction matters, including:

Foam density
Panel size
Reinforcement
Hinge layout
Vapor barrier
Exterior material
Proper fit

Locking Tie-Downs Are Available

We can add locking tie-downs to oversized and swim spa covers.

These tie-downs help secure the cover when the spa is not in use.

However, oversized covers over 96 inches do not carry an ASTM child-safety rating.

That distinction is important when choosing a cover for a spa used around children or pets.