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Clay & Concrete Tile roofing

 

Tile Roofing

Tile roofing has been used for thousands of years to cover buildings. Superior construction techniques and tile development has added to the durability of roofing tiles. The majority of tiled roofs can be repaired and restored without re-roofing. Call crown roofing for a free advice on your tiled roof. 

 

 

Tile roofing repairs and restoration

If your tiled roof is leaking, changing a tile may be all that is required to solve the problem. Other reasons for roof leaks can be loose or cracked mortar, faulty roof flashings or blocked rain channels. Painting your roof will not stop it leaking. Call today for a free estimate .

Cracked or loose roofing mortar on tiled roofs

Mortar on tile roofing is used on the ridge, hips, verges and some valleys to secure and waterproof the roofing components. With age the mortar may crack or lose its bond with the roof tiles. Ground and building movement can also cause the cement to crack. This may cause your roof to leak. In high winds the ridge tiles will be unsecured and may be lost. The remedy is simple and does not require re-roofing. The old mortar is simply re-pointed with either Flexi-point roofing compound or a traditional cement mix.

Are roof tiles porous?

Roof tiles are not porous to any great extent. Tiles have been used for thousands of years in much wetter climates than New Zealand. If your tiled roof is leaking, it is not because the roof tiles are porous. If the tile is cracked or broken, it will leak. Clay roof tiles absorb about 5% of their weight if they are fully submerged in water. Concrete roof tiles absorb upto 10% of their weight if they are completely soaked under water. If you have been told your roof tiles are porous you should certainly be wary and seek a second opinion. The BBC exposed this well rehearsed scam to sell new roofs. You can view the BBC Rogue trader episode here.

Concrete roof tiles are made with fine aggregates and cement. As the concrete roof tile gets older, it becomes harder. This type of concrete in known as non pervious concrete or non porous. If you are worried about your roofing tiles being porous, a simple test will put your mind at ease. A roof tile is removed from the roof and dry weighed. The tile is then soaked in water for 24 hours and weighed again. You will find the tile has absorbed very little water. 10% of the tiles bodyweight is acceptable.        

 

 

Does moss damage tile roofing?

Tile roofing often accumulates moss and algae.  As well as being unsightly, Moss holds moisture on the surface of the concrete tile and may lead to early deterioration of the tile coating. However, this has little or no effect on the strength of the roof tile. Any serious damage caused by moss will only happen during periods of ice and frost.  During a frost the moisture expands and may cause cracking and pitting of the roof tile surface. This is most noticable on clay tiles, concrete tiles are very rarely damaged by moss.

Moss also tends to block the hidden channels between the roof tiles. Roof tiles are joined together with a connecting channel that allows excess water to drain harmlessly down the roof. If the channel of the tile becomes blocked with moss, it may cause a roof leak.

To prevent this, you can treat your roof with a good fungicidal treatment. This job is best left until a dry day in summer. The frequency you need to repeat the treatment will depend on your roofs location and weather conditions.  As a rough rule of thumb, every 5 years should be sufficient for most tile roofs. 

 
Written by simon cowham. information@roofing.net.nz