The other day I spoke to a gentleman who asked me, to confirm to him that he needs to replace his concrete tiles on his house with clay tiles, I questioned his rationale and a mountain of misleading statements flowed from his mouth, perhaps the most memorable was that “as concrete tiles become older they start to leak and there is nothing short of replacing them with clay tiles”
I must say I have heard many such rumour floating around, all of which I am hopefully about to dispelled. I decided to see if the concrete tile manufacturers have become aware of these rumours and what if any, their official response was?
After talking to several people connected to the concrete tile industry, a brochure was mailed to us prophetically titled “THE FACTS ON CONCRETE TILES”
I will summarise and add some of our own comments to the questions and topics covered in this brochure.
“ARE CONCRETE TILES DURABLE?”
The modern manufacturing process makes the tiles exceptionally durable, they are manufactured to Australian standards and the physical properties of concrete will remain unchanged well in the excess of fifty or more years, irrespective of climatic conditions. Concrete actually becomes stronger with time and remember concrete is the preferred material for major structures such as bridges and high rise towers because of its inherent qualities of strength and longevity, additionally it out last other roof cover materials as it does not rust or corrode.
“DO CONCRETE TILES ABSORB WATER AND THEREFORE DOUBLE IN WEIGHT?” No this is incorrect and a myth. The Australian standards AS1757-1989 actually specifies a maximum water absorption of only 10% per total immersion in water for 24 hrs. In practice the absorption of water by capillary action during periods of heavy rain would increase the weight of the tile by around 5%. Contrary to claims of some roofing companies, this weight increase is unlikely to cause structural roof or stump failure.
“DOES WEATHERING OF THE ORIGINAL TILE COATING MAKE TILES POROUS?” Not true. The colour coating is purely decorative and is not designed as a water proofing film. As in most water proof purpose made concrete, water proofing is achieved by using carefully selected, formulated, batched and graded materials which are then compacted during manufacture. This then produces a concrete product of high density and strength which naturally keeps out water.
“ARE CONCRETE TILES FIRE RESISTANT” yes they are totally incombustible and fully fire resistant according to ASTM (USA)E108-88 tests, there is no comparable test available in Australia.
“WHAT ABOUT THERMAL AND SOUND INSULATION” Tiles take longer to heat up and tiled roofs usually have a larger volume roof spaces which “breathe” so houses with tiles roofs stay cooler longer, but once the heat build up accumulates for long periods, it also works in reverse that it takes longer to cool down.
Due to the greater mass of concrete tiles they do provide a better sound insulating quality than metal roofing, they help to reduce to noise intrusion in particular caused by rain and hail.
We will continue to discuss the myths and facts of roof tiles