AF Terracotta Roof Tile Restoration Adelaide

Terra cotta tiled roofs are a popular selection in Adelaide. There durability and permanent colouring make them ideal for home construction. The tiles themselves will generally last for up to 100 years and undergo little or no fading throughout their lifespan.

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Like all roofs, however, periodic maintenance is required. Valleys can rust and roof flashings, like the surrounds of a chimney or the pipes in your roof, can fail and require replacement. The mortar that sits under the longer edge caps (known as ridge caps) frequently cracks and becomes dislodged. This concrete is designed to secure the ridge caps in place. When it fails the ridge caps can blow off in high winds.

Unglazed or semi glazed (two tone) terracotta tiles are also prone to lichen growth. While low to moderate lichen growth does little damage, it can be unsightly. Heavy lichen growth can impede the effective discharge of rainwater from your roof and cause leaks. Because lichen imperfectly
covers the tiles, it can cause them to heat irregularly. This creates stresses within the tiles that can increase the amount of breakages that occur on older tiles on hot days. We recommend having the lichen removed from your roof when you elect to have it repaired.

Lichen is a symbiotic plant that requires algae to survive. Algae is attracted to the excess moisture and dirt that builds up on an unglazed terracotta tile surface. The lichen then forms over the algae and assists it by holding extra moisture in its body keeping the algae alive. The algae in turn provides the lichen with a grounding system and additional nutrients. After the lichen and algae has been removed, the best way to impede its regrowth is to apply a glaze to the tiles. This prevents the unglazed areas from absorbing excess water and assists in dirt pickup prevention. As a side benefit, it also restores the original gloss level to the tiles and improves heat reflectivity.

Our Process

Below you will see our step by step guide on how to successfully restore a terracotta tiled roof. Additional information can be obtained by scrolling down to our FAQ section.

1. Safety

All work on roofs require physical edge protection to be erected by law. Falls from roofs are amongst the most common workplace injury. If our tradespeople don’t feel safe, they also find it difficult to provide you with the high quality we demand. Prior to commencement of any of our roofing projects, full perimeter rail is erected around the roofline.

2. Broken Tiles

Most older roofs have a significant percentage of tiles that have minor chips and damage. The vast majority of these will never pose an issue and not be visible from a distance. Some tiles, however, may have breaks large enough that water ingress might occur. The first step after the rails are up is to thoroughly assess the roof and locate and replace any broken tiles that might be likely to leak.

3. Roof penetrations

Roofs generally have numerous pipes coming through them that are either sewerage vents or heat flus. The older style lead flashing on these can often split and fail. These are all carefully checked and any faulty ones are replaced with a new style Dektite flashing kit (seen below). The rubber sleeve prevents moisture from running down the pipe into the home and the flexible acrylic mat base is far more resilient than the old style lead bases that were used.

4. Chimney Flashings

Chimneys are a very common water ingress point. This is because they are a large roof penetration that rely on multiple metal or lead flashing components to prevent water from entering. These flashing components can often fail. They are made up of a rear gutter called a soaker tray, steel plating on the sides called hanging or step flashing and lead trim around the sides and front. All of these components are thoroughly examined for defects. In the cases of older homes, we generally recommend having all components replaced.

5. Valley irons

Valleys in roofs are the metal gutters that exist between opposing roof slopes. They convey water from the internal intersection of the faces down to the guttering. As they are a collection point for dirt and debris, they often begin to fail after 20 years or so. With all full roof restorations on homes over 20 years, we always fully replace all valleys in Colorbond steel. Valley tiles were traditionally secured to the valley using a concrete mix. The steel expands and contracts over time which can result in the concrete bedding working loose. Rust also develops much quicker under the concrete. Therma-Guard Roof Restoration utilises a special adhesive foam rubber compound that binds and seals the valleys to the tiles much more effectively.

6. Fungicide Treatment

Prior to cleaning, the algae and lichen on the tiles must be neutralised. Cleaning the roof without killing the spores will result in very rapid regrowth, sometimes as soon as a few months. We utilise an industrial strength chlorine and water solution that is evenly applied across the roof and left to sit for at least two hours. The chlorine is effectively kills the fungi as well as the spores ensuring regrowth is significantly delayed. The bleaching qualities of this chemical also assist in removing staining on the tiles that occurs due to long term lichen growth.

7. Pressure cleaning

Lichen growth, particularly if left for many years, creates unsightly stains on a tile that can remain even after pressure cleaning. For this reason it is imperative that an industrial strength pressure cleaner is utilised to remove the lichen and as much of the staining as possible. Our cleaners can generate a staggering 4,500 pounds of pressure per square inch. That’s around six times as much as a domestic cleaner could produce. This pressure, in combination with the bleaching qualities of the chlorine solution, will remove all but the most stubborn of stains. Anything left is unlikely to be visible from the ground. Such is the pressure applied that faulty tiles with hidden cracks will often break under our cleaners. These tiles are also replaced.

8. Clear protective glaze

The final stage of the lichen prevention process is the application of our tile glaze. AF Prestige Roofing terracotta tile glaze is a protective compound that is designed to increase the life of your roof, minimise the frequency of future repairs, greatly impede the regrowth of algae and lichen and significantly improve the visual appearance of your terracotta tiles. It is an advanced membrane that incorporates a clear pure acrylic with UV stabilisers, added polyvinyl acetates for increased adhesion and silicone for increased strength. Additional fungicides are also present in its liquid form. These are there to ensure any stubborn spores left from the pressure clean are killed also. The fungicides evaporate away as the coating dries. Our glazing system has a mid to high gloss level that will bring your roof back to a brand new appearance. The UV reflective qualities and gloss level also assist in infrared reflectivity which will significantly reduce the tile temperature which in turn will also help to keep your home cooler. Two separate applications are applied for additional protection. The membrane is completely waterproof so it will protect both the tiles themselves as well as the bedding mortar and roof flashings. All of our tile coatings are safe to collect drinking water

Our approach to roof restoration is designed in bringing the best that technology has to offer in terms of appearance and quality and combining that with advanced heat protective science. The end result is a fantastic looking roof that will endure for decades, look as good as a new roof-and perform better!

Frequently asked questions

Can you paint a terra cotta tile roof?


It is possible to paint terra cotta tiles but not recommended. Terracotta tiles are a problematic surface when it comes to applying solid colour coatings. Unlike concrete tiles, the surface is relatively nonporous. Where a steel surfaces can be adequately primed and coated, the same process is not effective long term with terracotta tiles. Terracotta tiles hold moisture even after they appear dry. This causes them to produce emissions in the form of steam. It is a slow process, but definitely there. A very good primer will prevent these emissions from causing peeling for many years, but not forever. The problem with a roof is how, once it starts to peel, do you remove the old paint? The answer is either very slowly, by hand with sandpaper (an enormously labour intensive process), or very expensively by sand blasting. When the tile begins to peel, and it definitely will, even the absolute best coating systems won’t last beyond 10 years, the roof will look terrible. In most cases, a previously coated and peeling terracotta roof is replaced with new tiles. The alternatives are just to expensive speaking relatively. We strongly recommend applying a clear glaze to prevent rapid lichen regrowth and to protect the tiles. While this too will peel eventually, it’s transparent structure makes it a largely invisible process. We definitely do not recommend painting terracotta tiles.




Can I change the colour of my terracotta tiles?


Yes but it is not recommended for the reasons stated above.




How long do terra cotta tiles last?


Different types and makes last for different lengths of time obviously, but a reasonable quality tile will last as follows. Unglazed, 80-100 years or around 40-60 if within 2 KM of salt water. Semi glazed (usually multi coloured), 90-120 years or 40-60 years if within 2 KM of salt water. Fully glazed and double glazed tiles, over 100 years, but the glaze can flake off from heat stress much earlier. The solid surface offers no respite from expansion and contraction. The same limits exist if close to salt water.




Why does lichen and moss grow on my terra cotta tiles?


Lichen requires algae to grow. Algae is attracted to damp dusty surfaces that have some shelter from the sun. Algae generally begins to grow on the noses of the tiles and in the shadowed area close to the overlaps. The lichen then grows over the top which provides the algae with additional moisture that is held in the lichen. The lichen also protects the algae from direct sunlight so it becomes more robust. During extended cloudy periods or over winter when there is less direct sunlight, the algae, and the lichen, begin to spread outwards. It is not uncommon to see some roofs completely covered by lichen growth even if they are exposed to a lot of light. The lichen, by the way, gets nutrition from the algae itself as well as having better foundations on which to grow. Both algae and lichen are largely air fed organisms. They require only moisture and air to survive and are extremely proliferate.




Will lichen and moss damage my roof tiles?


There is no direct damage associated with lichen growth. Lichen and algae have no root system so are not invasive. There are, however, several subsidiary issues that occur from lichen growth. Older tiles become brittle. Lichen growth, which tends to be uneven, cause the brittle tiles to heat unevenly in the hot sun. Many years of this irregular stress can cause the tiles to break on extremely hot days. The main issue with heavy lichen growth, however, is that it can impede the flow of water from your roof. It creates blockages in the water course that can cause significant water ingress during extreme weather events. We recommend having the lichen removed when roof maintenance is carried out. A sophisticated acrylic glaze can assist greatly in preventing regrowth.




How can I remove lichen and moss from my roof?


Standard domestic pool chlorine is something that will have limited success. Mix up a strong solution and pour it liberally over the lichen. After a very heavy rain you should start to see some lessening of the lichen. This will need to be done periodically, around every 6-12 months, for it to have lasting visible effects. Be extremely careful though, working on roofs without scaffolding is very dangerous and the chlorine can make the roof slippery! Galvanised steel straps or copper wire along the ridge caps is another slow working method. These can react with guttering so be careful. Staining on the tiles can also result. Neither of these are going to remove more than 60% or 70% though. Pressure cleaning first is better and then the above steps. Effective pressure cleaning requires very high pressure that is likely to damage pointing and roof mortar. It is also common for inexperienced people to flood the interior of the home. You should never attempt any work, particularly cleaning that involves the use of water and has hoses that become trip hazards, without full perimeter railing. Generally it is best to leave roof work to the experts though. It is safer and more effective in the long run.




Can you seal terra cotta tiles?


Yes. There are many different products on the market that can be applied to terra cotta tiles to prevent them absorbing water and limit moss and lichen growth. These should be applied by a qualified contractor that has had experience in terracotta roofing. Many products used have additives that make them cheaper to buy. Unfortunately, additional compounds in an acrylic soon discolour in UV rays. This is less noticeable in coloured paint, but clear coatings can go an off white or yellow colour. A good terracotta glaze will be a pure acrylic base that incorporates polyvinyl acetones and UV stabilisers.




Should you seal terracotta tiles?


Fully glazed tiles should not be sealed. They have a protective glaze that is far more durable than any retro applied glaze will be. Semi glazed and unglazed tiles, however, can benefit enormously from professional glazing. A high quality glaze will prevent water absorption, limit lichen growth, extend the life of a tile and improve the appearance of a roof enormously. Higher gloss levels will even assist in keeping the tiles, and therefore the home, cooler. Shiny surfaces reflect both UV and infrared light.




How much does it cost to restore a terracotta roof?


Like any roof restoration, the cost comes down to how big, how much work is required, and what type of quality is applied. The average cost to install scaffolding, replace all concrete and roof flashing, treat the lichen and high pressure clean the roof and to apply a couple of coats of a high grade acrylic glaze is around $8,000 to $12,000 for an average home.





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