Why does my roof leak? There’s obviously so many possible answers to this question…but we can simplify it more or less. Yes, it’s true that an older roof will leak but newer ones leak as well. On an older roof the shingles are more likely to blow off as they don’t adhere to each other as they once did…nails pop out (roofing nails do not have threads on them and are only going into 3/8” of plywood in newer homes), shingles are worn out between the tabs (traditional looking shingles are called “3 tabs shingles” as that’s what they consist of) and flaws in the installation show up over time etc. [pic 009 McConvey;032,033,34 of 18 Glen Oaks] While it’s true that shingles wear out first on the south and west sides due to the sun it is also true that the freezing and thawing that happens all winter advances the wear and tear whereas the north and east sides last longer due to the difference. So the fact that old roofs leak is no surprise…they have a limited lifespan.

But why do newer roofs leak? You could say that it has more to do with improper installation due to inexperience, incompetence or just not caring…and you’d probably be right in my opinion. I’m not sure whether or not a new roof put on in a new subdivision has had anyone inspect it. Doesn’t appear to be so. I’ve been on countless brand new roofs that didn’t have one ounce of caulking on any exposed nails (used to secure pipes, vents and flashings). I presume our “minimum” building code would require sealing of all exposed nails, finishing seams etc. If you’re sitting comfortably in your home thinking that your roof must be fine or an exception to the case because you aren’t aware of any roof leaks perhaps you might want to think again. Remember nowadays your attic has a lot of insulation in it (perhaps 10 or 12 inches of it). It’s going to take quite a while or a pretty bad leak before it shows up on ur ceiling…in a lot of cases it’s just long enough for the new roof warranty to expire.
Almost one for one when I inspect a new home with it’s new roof in a new subdivision I find: no nails or finishing seams sealed, wrong vents used to vent the 2nd floor bathroom fans. There is such a thing as a bathroom vent that actually looks different than a roof vent. Works better too. Take off the improper vent (roof vent) after a couple of years and see if the wood isn’t water stained and/or blackish in color. It can’t be a good thing when plywood is turning black.

Roofs can leak because shingles blow off. Normally they blow off in very strong winds. The houses that have this reoccurring problem are usually situated in a location susceptible to strong winds (eg. Across from a park or open field or homes in higher elevations than surrounding homes.) Believe it or not the shingle manufacturers have actually made mention of the fact that extra nails should be put in the shingles in heavily winded areas. I have seldom seen their advice taken.  So missing shingles on a roof (due to wind or animal damage or old age) can cause a roof leak if the area now has exposed wood. Worn out shingles can cause leaks because ,again, the wood sheathing is exposed.

What else causes a roof to leak? Many things: a single nail worn through a shingle (pic); animal damage to bathroom pipe flashing (pic); improperly installed bathroom pipe flashings (pic)(pic); unsealed pipes; unsealed vents (pic); improperly installed vents; worn out asphalt valleys; holes in metal valleys; nails too close to valley edge (pic); improperly installed chimney metal flashings; improperly sealed chimney metal flashings; improperly installed or sealed wall flashings; faulty brickwork in flashing areas; split level home leaks…

Conclusion: It’s not a perfect world so even if you have a brand new house it’s not necessarily a bad idea to have the roof inspected before that minimal warranty expires and the roofing company has moved on to their next project. It’s not a bad to have your new roof inspected on an older home before you pay for it. It’s not a bad idea to have your roof inspected for routine maintenance…after all your insulation can only take on some much water.