Terracotta Tiles: Roof Restoration or Roof Replacement?

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Image Above: A 40-year-old glazed terracotta roof during a roof replacement conversion to insulated Colorbond.

Terracotta tile roofs can be found throughout Adelaide. Typically sported by older and more established suburbs, terracotta tile roofs were most prevalent from the 1800s to the 1990s. However, this iconic roof cladding comes with its own set of pros, cons, and limitations.

When homeowners undertake terracotta tile roof restorations in Adelaide, they often stumble across a range of problems. Due to the complexities involved with undertaking roof painting, or replacing these characteristic tiles, a homeowner may ultimately have to make the choice between a roof restoration process or a full roof replacement.

In this article we’ll provide a comprehensive overview of the options available to owners of a home with an ageing terracotta roof and the best steps to take to preserve longevity of your property.

Image Above: A typical non-glazed terracotta roof on a house built around the 1930s in Adelaide. Note the patchy areas are fretting.

The History of Terracotta Tiles

The noun terracotta comes from the Latin “Terra Cocta” and, in direct translation, means “cooked earth”. The material was common throughout Asia, the Middle East and Europe for thousands of years, with its origins dating back to China, 10,000 BCE.

The popularity of this roof type came from its relative ease of local manufacture. Past eras lacked modern transport and handling machinery, meaning that heavy building materials like terracotta roof tiles had to be manufactured relatively close to the dwelling for which they were intended.

Because terracotta tiles are assembled from clay soil, any region with access to clay deposits and timber to fire kilns could manufacture objects from terracotta. While terracotta never fades and is considered an eco-friendly option for roof cladding, it is also a porous material susceptible to moss growth and fretting.

Image Above: A terracotta tile in the late stages of fretting. This tiled roof was only 39 years old and around 2km from the ocean but had utterly failed. As roof restoration could no longer be considered a viable option, this tile required complete replacement.

Fretting Terracotta Roof Tiles

Of the thousands of Australian roofs clad with terracotta, many encounter the problem of fretting. Fretting describes the process of a tile crumbling and breaking up, returning to the clay from which it was made. The tiles tend to emit orange residue into the roof space and slowly leave terracotta dust and chips to collect in gutters. While fretting in its later stages can be easily spied from the rooftop by visible chips and chunks of missing tile, it will be most prevalent in the laps of the tiles, the areas where one tile covers another.

Once fretting has started in terracotta tiles, they become so brittle that they are no longer trafficable and will break and crack if walked upon. Coastal conditions accelerate the fretting process in many terracotta roofs. Indeed, some roofs show significant fretting when not even 40 years old. While in Europe it is common to see terracotta roofs that are hundreds of years old, it’s likely the different clay types that were sourced from various geological sites that ultimately lead to varying lengths of serviceable life in tiles. The fretting process of terracotta can not be reversed and will deteriorate as time passes. At this point, a roof restoration is not a viable or possible option for the terracotta roof, and the only option remaining is a total roof replacement.

Terracotta roof tile Replacement Options

While there is no roof restoration option for fretting terracotta, there are two distinct replacement options. First, the roof can be fully replaced with new terracotta roof tiles. While it can be expected that a modern terracotta roof will outlast the old, this option is far less popular than the second option; a conversion to insulated Colorbond metal roofing. This option gives many benefits to the home and is usually somewhat less expensive than replacing a roof with new terracotta tiles.

Above Image: A complete roof replacement conversion to Colorbond with around one-quarter of the roof currently replaced.

The Benefits of Colorbond roof replacement

Cost Savings

A Colorbond roof replacement is approximately 10 – 20% cheaper than the equivalent roof replaced with new terracotta roof tiles. You can expect to pay about $100 per square metre for conversion to Colorbond. This approximate figure is based on an average-sized single-story home with good access and a standard roof pitch of 22 – 25 degrees.

Roof Insulation

With a conversion to Colorbond comes the option of insulating the roof. This refers to insulation directly under the roof sheeting (not the ceiling). In most tile roofs, this is not an option. The Roof blanket insulation prevents heat from entering the roof space right at the roof surface. Another significant benefit of the Colorbond roof is the reduction in ambient noises such as traffic and aircraft but most notably, the drop in audible rain and hail on the rooftop. The best brands of roof insulation for your roof are Fletcher Insulation and CSR bradford Anticon Roof blanket. These are both top quality and Australian made. When installed correctly, the difference in noise for an insulated roof vs a non-insulated roof is significant and almost as quiet as a tile roof.

Image Above: A roof replacement during re-installation. Note the blue metals roof battens fitted at 900mm centres and the foil-backed 50mm glass wool insulation blanket.

Weight reduction

The weight difference between a terracotta tile roof and a new Colorbond roof is around 10 to one. That means for every 10 tonnes of tile removed, only one tonne of Colorbond roofing material is installed. The average weight of a terracotta roof on a four-bedroom home is 16 – 18 Tonnes. The total weight reduction with this conversion type is significant and helps halt future sagging of structural members and cracking in solid brick walls.

Appearance & Value

Modern Colorbond provides diverse colour options guaranteed to suit any home. Many homeowners select a colour sympathetic to the original terracotta roof, such as Manor red. Others opt to modernise their home and choose a more minimalist colour such as Surfmist or Monument. Following a roof replacement, you can expect your property value to increase by at least the cost of the upgrade, if not more. When selling the home, you will not have to worry about prospective owners conducting a building inspection only to find a fretting terracotta roof and requesting a reduction in the contract price to reflect the replacement cost.

Image Above: A completed roof replacement. Fully Insulated and clad with Colorbond Monument.

Roof Replacements: Understanding the Process

The roof replacement is a simple process and often takes around one week or a little more.

The roofing contractor will usually try to place large skip bins as close as possible to the roof’s edge to allow the workers to throw the old roof tiles off the roof and straight into the skip.

Following the tile removal, the whole roof is framed with metal roof battens installed every 900mm. The battens serve as the fixing point for the new Colorbond roof. Original timber tile battens remain but no longer serve any purpose on the roof. Once the metal battens have been installed, the next step is cutting and fitting the foil-backed roof insulation blanket. The workers carefully place the insulation blanket to cover all roof areas and create an airtight roof space.

Finally, the Colorbond roof sheeting is installed, and screws are put in to secure it. The result is a robust, well-insulated and airtight roof.

Homeowners can stay home during the process, with the only real bother being skip bins in the driveway and some noise created by workers on the roof.

Finding a Qualified Roofing Contractor

If you are ready to replace your terracotta roof, it is essential you find a reputable and qualified roofing contractor. When looking for roof replacement specialists, it’s vital to consider some critical factors, including checking for a licence, warranty, insurance, and investigating the contractor’s completed projects. We highly recommend reading our informative article, ‘9 Things to Consider When Selecting a Roofing Contractor’, for a full guide to making an informed roof restoration investment.

Summary

If you have an ageing and possibly fretting terracotta roof and are struggling to find anyone willing to conduct re-roofing, then the reasons outlined within this article may help explain why. The investment is often worth the reduced power bills and increased property value. A roof replacement from terracotta makes sense when looking at the years of extra service you can obtain for your home.

At Oz-Roof, we specialise in all kinds of roofing services and replacements, from concrete tiles to terracotta and metal roofs. Our quality work, competitive roof replacement costs and fully licensed team are guaranteed to deliver a roofing job that any homeowner can be proud of. If you’re looking for a roof replacement crafted from tried and true Australian roofing materials, be sure to get in touch with us today. With Oz-Roof, expert advice and quality service are only a phone call away.

Happy Roofing

The Oz-Roof Team

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