Tiled Roofs on WA Residential Homes – Do they last forever? What are the issues that Home Buyers and Sellers need to consider? 

1. What are we talking about? 

Historically West Australians have had a love affair with double brick homes and tiled roofs. This is unique to WA and exists nowhere else in the world! Whilst this is changing we still have literally thousands of WA homes with tiled roofs. Sadly these key components of our homes are often neglected, out of sight out of mind, so given our recent winter rains this key part of our homes deserves a much needed review. 

• Tiles do not last forever
• Tiles break 
• Tiles need to be maintained
• Tile supports need to be replaced
• Waterproofing capabilities break down 
• Tiles break down
• Caution if you swap to metal roofs

2.  Are all roof tiles the same?

Not all tiles are the same. In WA we are essentially talking about clay tiles and cement tiles. 

1.1  Clay Tiles

Clay roofing tiles are manufactured by baking moulded clay. The density of your roofing tiles will depend on two factors:

(1) the temperature at which the roof tiles are heated

(2) the length of time they are heated.

Generally, clay tiles will come in a range of colours such as brown, yellow, orange and mixture of these colours. The most common clay roof tile colour is Terra-Cotta. One alternative to natural earthy tones is to add enamels to the manufacturing process.  By spraying enamel over the tile before baking it at high temperatures, you can bind a colour of choice which prevents fading or peeling. As a result of ceramic binding in the kiln, you may choose from a larger variety of colours, profiles, styles and finishes.

Clay tiles are manufactured from natural earth materials which allows for environmentally friendly recycling. The largest draw back of clay roof tiles is cost as they are the most expensive of the two roof tile options. If maintained clay tiles should last longer and retain the colour longer than cement tiles but as the clay tiles age they will be more fragile and likely to shatter if incorrectly walked on. 

In some cases clay tiles can be harder to install on a roof than cement tiles.  Clay roof tiles often come with a 50 plus year manufacturer’s warranty. 

1.2  Concrete Tiles

Concrete roof tiles are made from a mixture of water, cement and sand. The mixture is then moulded under high pressure and extreme heat. The surface of the concrete roof tile may be finished with paint like material.

Concrete roof tiles come in a variety of colours, profiles and shapes that may complement and contrast your home’s aesthetics. The surface of concrete roof tiles can be smooth or textured, and tile edges may be uniform or ragged. With the advent of new production techniques, you can pick between a traditional look and something more modern. If cost is a major consideration, then concrete tiles are more cost effective to both produce and install versus clay roofing tiles. Concrete roof tiles are usually the cheaper option. 

Concrete roof tiles are tough and also generally come with a 50 year performance guarantee. 

Concrete roof tiles have a water absorption rate of about 13%, compared to clay, which has an absorption rate of about 6%. This means a higher likelihood of algae and mildew growth. Some sectors will suggest that concrete roof tiles will usually have a life span less than clay tiles. 

Concrete tiles are heavier and come in at around 430 kilograms per sqm whereas clay tiles will generally come in at circa 300 kilograms per sqm. Hence your property may require more additional support to have a concrete roof installed.

3. Number One Issue – Water, Water, Water, 

Ok we are stating the obvious here. One of the primary jobs of tiles is to keep water from entering our homes. So anything that adversely impacts on the ability of the roof tiles, to effectively drain water off the roof into the roof pluming or off the roof entirely, needs to be addressed. 

Cracked, broken, loose, moved, dislodged and missing tiles need to be replaced or relocated or refastened. 

Let’s be clear, silicon repairs to tiles are not a long term solution! Silicon will break down over a number of years. Silicon is a great short term solution for emergency repairs of roof tiles but it is not considered a long term solution against the life of roof tiles. Broken and cracked tiles need to be replaced.

Tiles will move or be dislodged or become loose for a variety of reasons. When this occurs the tiles need to be repositioned and refastened as soon as possible.  

4. Lichen 

Lichen grows on tiled roofs and restricts rainwater from effectively entering the roof plumbing. It can contribute to water ingress and degradation of roof tiles. Lichen needs to be removed from roof tiles.  

A lichen, or lichenized fungus, is actually two organisms functioning as a single, stable unit. Lichens comprise a fungus living in a symbiotic relationship with an alga or cyanobacterium (or both in some instances). There are about 17,000 species of lichen worldwide. (https://www.livescience.com/55008-lichens.html)

5. Ridge Capping

Ridge caps are essential the top ridge of two elevations of tiles. On top of the ridge, a ridge cap tile is bedded on a cement /lime or specific flexible bedding point mixture to seal the joins between the two tile elevations. See here for an example.

The ridge cap tile bed must be kept in good repair so as to ensure the ridge cap tile does not move and the potential for water ingress is minimised.  

6. Resealing Concrete Tiles

This is probably one of the most controversial areas in relation to roof tiles. Concrete tiles are essentially painted and this paint provides additional waterproofing protection to the actual tile. Given the tile is exposed to the elements, the surface covering of the tile will breakdown over time. This can increase the extent that tiles will absorb water and this may impact the transfer of chemicals and moisture to the underlying wood tile batten (see below). According to the CSIRO,  the breakdown of the protective covering on roof tiles is unlikely to result in substantial water ingress into the home. 

However, faded concrete tiles on a roof may detract from the overall aesthetical appeal of the property and as such repaint/sealing the roof tiles may improve the overall appearance of the roof.

But starting the painting processes needs to be undertaken with an understanding that:

• Once painted, concrete roofs are likely to require repainting every 5 – 10 years for the appearance to be retained.
• It is important to check the economics. Will the investment in repainting the roof be reflected in the value of the property. 
• Roof restoration has attracted the full spectrum of trades. It is important to shop around and ensure you have a quality provider.  

7. Fretting Roof Tiles

Fretting can be caused by a number of reasons and is not often obvious from looking at the top of the tile. Generally you will need to inspect the tile from the underside by entering the roof space (if no sarking is installed) or by turning the tile over. If fretting is present, you will notice the clay starting to become flaky and breaking down, this will typically make your tiles brittle and easily broken especially when walked upon. The issue is generally associated with age of the clay tiles and can extend from individual tiles to the entire roof cover. The only solution here is to replace the fretting tiles which may mean replacing the entire roof.

8. Delignification of Tile Battens

Tile battens are strictly not a part of the roof tile, but their sole purpose is to support the roof tile. As we have already written, tile battens can be adversely impacted by chemical delignification whereby the batten essentially breaks downs. See here from more details. 

Ensuring that your tiled roof is properly maintained requires an inspection of the roof battens. In some cases, roof battens will need to be replaced so as to ensure the roof tiles remain securely attached to the roof and safe to walk on. 

9. Tiles which have come to the end of useful life

As we started in this article, tiles will not last for ever.  Environmental factors and the extent of regular maintenance may result in some tiles lasting longer than others and some may outlast the life of the building. 

However, on occasions roof tiles will need to be replaced. The tiles can be replaced with another tile or converted to a Colorbond metal roof. These conversions are generally straight forward, but in WA we see far many situations where the conversion is simply not done as required.  See here for more details. 

10.       Important Information for Buyers and Sellers of Residential Property in WA

In WA the majority of Residential Property Purchase Contracts which incorporate a Pre Purchase Building Inspection utilise the REIWA Standard Clause Pre Purchase Building Inspection Clause which relies on Appendix 1 of AS 4349.1. Surprising for some, this Standard and the REIWA clause specifically excludes the condition of the roof cover under the definition of Major Structural Defects. Roof tiles are not a Structural element of the building. 

For Sellers this is a very positive position. Irrespective of the condition of the roof cover there is nothing in the standard REIWA clause which will enable the Buyer to claim the cost of roof cover repairs from the Seller. 

For Buyers the news is negative. A pre purchase building inspection report may identify significant issues with the clay or cement roof tiles but essentially the Buyer will not be able to invoke the standard REIWA pre Purchase Clause because the roof tiles are not considered a structural element. The Buyer may be faced with a bill of many thousands of dollars with no ability to recover the costs from the Seller or any ability to terminate the contract. The position is in fact worse. There are some Agents in WA that mandate the strict application of Appendix 1 of AS 4349.1 and the REIWA clause such that Major Defects associated with the roof tiles are not even permitted to be reported within Pre Purchase Building Inspections!  

11.       Conclusion

Roof tiles in WA have been extensively used. For many years there were considered the preferred roof cover. They can last for more than 50 years but they do require maintenance. You cannot ignore them. 

We have identified some of the key issues associated with tiles and the requirement for ongoing maintenance. 

If you are buying a home with tiles, especially older homes, caution is required especially if you are intending on relying on the REIWA Pre Purchase Building Inspection Clause – in essence it excludes roof tiles. 

Houspect inspects roof tiles, roof plumbing and roof battens and roof frames.   If you need your roof inspected, call Houspect! 

July 2020 

Build, Buy, Invest in property (and roof tiles) with confidence  Ph 9240 8855 Web: www.houspect.com.au/wa Email: info.wa@houspectwa.com.au