How to maintain a cement tile roof?

PujDD

I’m looking for advice on the best maintenance approach for a 35-40 year old concrete/cement tile roof in Sydney.

My current plan is to reduce leak risk by softwashing + mould treatment, replace cracked tiles, and repoint ridge caps.

I've had 2 roof restoration trades quote me who advise that sealing and painting is almost mandatory here to reduce porosity of the tiles. However they both suggested power washing the tiles.

Is it necessary or structurally beneficial to reseal and repaint this roof, or is it mostly cosmetic?

I'm ok with making some cosmetic tradeoffs to a point, as I am planning a renovation in 2-3 years which will include a full exterior paint. However, I don't want to compromise the structural integrity of the roof and am prepared to seal and paint now if the condition of the tiles calls for it.

JacobZ

Hi @PujDD,

In simple terms, as concrete tiles age, the sealer that was originally applied during manufacture will wear away. Without this sealer, bare concrete tiles are porous, so they will absorb and hold moisture. Over time that can lead to things like increased moss or lichen growth, a bit more surface wear, and tiles staying damp for longer.

From a practical point of view, porosity on its own is not usually what causes leaks. Issues like cracked tiles, ridge pointing failure or flashing problems are far more common causes of leaks. Sealing and painting mainly helps by reducing water absorption and slowing that long term deterioration rather than fixing a direct fault.

So, if there are indeed cracked tiles or pointing failures, then they would be the priority over painting, but this is not to say painting is not required. I would tend to put some weight on the contractors’ recommendations. They are physically inspecting the roof and can see the condition of the tiles up close. If they are both calling out porosity as a concern, it likely reflects what they are seeing on the surface of the tiles.

If you are unsure, I'd ask the contractors to show you examples of what they are seeing to warrant painting. The decision then becomes less about whether sealing is required, and more about whether your specific roof is showing enough wear to justify it now versus later.

Ultimately, given the age of the roof, I'd say painting should indeed be done, it is just whether there is an immediate need for it right now considering the plans in the next few years. Given the advice of the restoration contractors, I'd say it is probably best that it is done now to avoid further issues, but ultimately that decision is up to you.

Allow me to tag our helpful members @Nailbag, @Dave-1 and @Noyade to see what they think.

Jacob