Carronite: Is It Designed to Last a Lifetime?

Often regarded as the gold standard in heavy-duty bath production, the patent for the world famous Carronite reinforcement system celebrates its 40th anniversary in 2026. We take a look at how it all began and celebrate the storied history of the company behind the process that changed bath manufacturing forever.

Founders & Foundries

A British brand with proud origins in Stirlingshire, Scotland, The Carron Company can trace its roots back over 250 years, to an ironworks on the banks of the river that the company is named after. After some initial struggles to get a foothold in an emerging manufacturing industry, Carron eventually won a contract to supply the British armed forces with their high-quality iron, to be used in the manufacture of weaponry.

In 1765, the Carronade, a short-range naval cannon pioneered by The Carron Company, was so beloved by the Duke of Wellington that he only allowed Carron-manufactured cannons to be used by the army. The Carronade even went on to play a key role in the Battle of Trafalgar. 

As the years went on, Carron turned their hand to a less-deadly suite of products, including stoves, engines, telephone boxes and the iconic red post boxes for The Post Office. Incredibly, some of these models are still in use today; a testament to their skill that has persisted over multiple centuries.

Making a Splash on the BBC

Carron began manufacturing cast iron baths in the mid-1860s, a decade after the novelty of a marbled private bath was shown off at The Great Exhibition in London. However, bath orders were few and far between; most Victorian homes did not have piped hot water.

Fast-forward to the 1950's and Carron products were making waves once more - a BBC documentary showcased their rich manufacturing history, including their cast iron baths and stories of people connected to the ironworks. The show drew a large audience and reaffirmed the Carron brand to a new generation of consumers.

By the 1970s, Carron had begun manufacturing baths from acrylic on a regular basis, as the popularity of the material soared. Despite the clear and obvious benefits of acrylic, there was 1 key problem to solve: the baths did not feel or behave like a cast iron or steel bath. Just as they had done in the 18th and 19th centuries, Carron were about to change the course of history with their innovation...

Patently Obvious

There was a clamouring amongst owners of hotels and resorts for a technology that felt more luxurious; a hardwearing and durable material suitable for high traffic and heavy use. Enter Carronite, a triple-layer reinforcement system that would turn a standard acrylic bath into something extraordinary. Think Bruce Banner becoming The Incredible Hulk... (minus the gamma radiation).

Although it may sound like an element in the periodic table, Carronite is actually a glass-reinforced resin, adding around 30% additional thickness to a typical tub, resulting in super-strength and enhanced insulation. The material is applied externally to the acrylic; a rigid reinforcement system that was the height of technology at the time of its conception.

Carron patented this manufacturing process in 1986, and the name has since become synonymous with the idea of a reinforced acrylic bath in the 40 years since. Much like a Hoover or a Flymo, the Carronite name is subconsciously etched into the brains of a generation of homeowners.

Thirty and Sturdy

The original mission statement from Carron was to create Carronite to provide a higher level of luxury, comfort, and peace of mind. Their innovative, patented process achieves a uniquely reinforced bathtub; so much so that it requires a bespoke fitting system to hold the extra weight.

The Carronite reinforcement process consists of 3 layers:

• The external layer - made up of a glass-reinforced resin, bulking out the thickness of the bath significantly
• The middle layer - an 18mm thick baseboard, total encapsulated between the top and bottom layers giving complete rigidity
• The top layer - 5mm thick, sanitary grade cast acrylic to provide a warm, hygienic, glossy finish to the tub

These 3 layers are complemented by a unique frame and leg set - designed specifically for the unique Carronite baseboard. The custom, cut-to-size baseboard is fitted by hand before the specially formulated resin layer is applied. A bespoke Carronite waste ring is also supplied, ensuring the perfect seal.

The number 30 is a metric that you'll hear a lot in association with Carronite, and for good reason. The unique process gives each bath the following benefits:

• The external layer adds approximately 30% additional wall thickness to the bath compared to a standard Carron model, giving it a sturdy look and feel
• A Carronite bath is typically 30% stronger than a standard acrylic bath - a famous marketing image shows 4 Carronite baths holding up a 7.5-tonne lorry
• On average, Carronite baths retain heat for 30 minutes longer than a standard bath; the ultimate choice for a relaxing soak
• Each bath benefits from a 30-year manufacturer warranty - raised to 40 years in 2025 to commemorate their 40-year patent anniversary, giving peace of mind on a similar scale to a cast iron or steel enamel model

Carron, and on, and on...

Carron continue to push the boundaries of contemporary bath design. Their sprawling range consists of hundreds of different models, in sizes to suit bathrooms at both ends of the scale, whether it's a traditional rectangular inset tub like the Britannia or the beautiful Celsius baths with their integrated waste and filler.

Some of our firm favourites in the Carron range are the Quantum, Profile, Swallow, and Delta - models that can blend in to any scenario, adding style and substance without the need to steal the limelight away from a vanity unit or walk-in shower - 2 products typically chosen for their aesthetic appeal.

HeatandPlumb.com have helped thousands of customers complete their bathroom renovation by specifying a Carron bath. We sell their standard 5mm acrylic models as well as the reinforced Carronite versions, giving customers the chance to own a market-leading bath regardless of their budget constraints.

Carron Bathrooms remain a proud member of the Made in Britain manufacturing campaign, and they've never forgotten where they came from - because they never left - they still manufacture their baths in Falkirk to this day.

Next time you're looking to purchase a new bath - whether it's a simple single-ended model, luxurious double-ended option, shower bath combo, or the lesser-seen corner tub - be sure to consider Carronite. We've been selling Carron baths online for nearly 2 decades, and we agree with the Carronite motto wholeheartedly, they're "designed to last a lifetime".