In the past, when buying and selling a home, not many home buyers necessarily had a professional roofing inspection along with their home inspection. But because general home inspectors suggest a proper tile roof inspection, it is happening more often. Why? Most home inspectors simply don’t have roofing experience and even if they did, a good roofing inspector needs ten or more years’ experience in order to properly judge a roof’s condition.
In the case of tile roofs, even experienced roofers can fail in judging their age but mostly it’s because they are too lazy to bother really digging in, and you have to. Because of course, the tile itself is probably either concrete or clay, and would probably last 100 – 200 years, maybe more (certainly we know clay can last centuries).
But a tile roof depends upon the waterproof membrane underneath. That membrane is covered with the tile, so unless you pull up some tile, you can hardly judge its age. Many roofers will examine the membrane at the edge of the roof but this will give you a false negative. The membrane at the very edge, where it is often exposed to harsher elements, is almost always going to be far more worn than the membrane further up, covered with tile.
I will usually take a sample of the membrane and, besides identifying its quality, can bend it and see how much asphalt oils remain – the prime ingredient in waterproof felt. It might be a high quality rubberized membrane of a type that has only been made in the last 10 years in which case a) we know it can’t be that old and b) it is high quality and will, in any event, last for decades. Most roofers use the cheap old 30 pound ordinary felt paper. I personally use a rubberized felt that is much heavier and can last over 60 years.
The bottom line is that if you are buying a home and particularly if it has a complicated or expensive tile or slate roof on it, it pays to find out what shape it’s really in by a qualified roof inspector. In some cases, I have saved clients from making a $50k mistake with a proper tile roof inspection.
(Read our last blog for more information on inspecting other types of roofing.)