Terracotta Roofs - To Restore or Not to Restore
Terracotta tiled roofs were a popular choice for Adelaide builders in days gone by with many older suburbs filled with moss and lichen covered homes protected by terracotta tiles. One question I get asked a lot is - should we restore our terracotta tiled roof?
Terracotta tiles are made from natural clay and fired at extreme temperatures to create strength, character and colour retention. They provide a low maintenance roofing solution with great thermal and acoustic performance. They are also a great solution for coastal areas where salt may damage other roofing solutions.
Unfortunately for many home owners, these tiles are starting to not only date, but frankly wear out. On basic inspection of an old terracotta roof a couple of obvious changes have occurred. Moss and lichen are a main feature as the protective glaze has worn away leaving an exposed clay surface which makes a great breeding ground for these living organisms. In addition to this, pointing and bedding is typically visibly deteriorated potentially leading to roof leaks and internal water damage. So should a terracotta tiled roof be restored?
Before answering this, let's look at the restoration process. When a tiled roof is restored, broken and chipped tiles are first replaced to ensure that no water leaks are present. This is followed by high pressure cleaning to remove dirt, moss and lichen and in the case of cement tiles any oxidised residual colour. Any loose ridge and hip caps are then re-bedded and all capping tiles re-pointed. A moss and lichen killer and inhibitor is then applied to the roof surface followed by a primer coat. Once the primer coat has dried, 2-3 coloured top coats (typically clear coats for terracotta tiles) are applied to seal the tiles, protecting them from weathering and adding street appeal to your home. This process will typically add another 20 years to the life of your tiles roof - so is this a good idea for terracotta roofs?
Unfortunately for terracotta tiles, there are two main issues with the restoration process. Firstly terracotta roofs suffer from what is known as fretting. 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 turn a tile over or look through roof cavity space (if no sarking is installed). 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 and is not fixed during the restoration process.
The second problem with the restoration process for terracotta tiles is the application of the sealant or membrane. Despite what many reps will tell you, I have found that the current roof membrane coatings on the market today are just not bonding to terracotta tiles as they do with cement tiles. This means that even with great preparation and correct application, it is unlikely that the membrane will not peal or flake. While this may take a couple of years to develop, it causes an unprofessional and badly painted appearance to the finish of your roof.
So what are your options?
Depending on the age of your roof and its condition, you have a number of options. If fretting is not a severe problem for your roof (tiles are not breaking every time you walk on the roof) your best solution may be to carry out some routine maintenance. This will include re-bedding, re-pointing, high pressure cleaning and applying a moss and lichen inhibitor. While this will not reseal your tiles, it will ensure your roof is free from obvious leaks and freshen up your roof adding value and street appeal.
Your other option is to re-roof. Over the last decade or so, South Australians have really taken to colorbond re-roofing and while this is certainly a great option, it is not the only option and in some cases it is not the best option. To find the best solution for you and your situation, it is best to speak with a reputable company who will provide honest advice. If you would like some assistance, leave a your details and a short message HERE