Recently while doing a pre-purchase home inspection in Tallahassee I encountered a major roofing defect that was caused by some simple mistakes that could/should have been easily avoided. As I got out of my truck, I could see the curling roof shingles all over the different roof slopes and knew that this roof was at the end of its useful life. Shingles that are showing signs of curling are a big deal to Insurance companies, I have seen insurance companies tell past clients they have 30 days to replace a roof or face cancellation of their policy, on roofs that barely had any curling and it was just on one of the 7 slopes. The four-point inspection report that is required for most older homes by insurance companies has a specific box asking if there is ANY signs of curling. Roof shingles are supposed to lay flat and be firmly adhered/ bonded to each other. Shingles that’s are curling are no longer fully bonded to each other, are going to be brittle, and more susceptible to wind damage.
Causes of curling roof shingles
Lets just list the 5 basic reasons why one might see curling roof shingles.
1. The roof is old and at the end of its useful (not fixable)
2. The roof shingles were installed incorrectly (not fixable)
3. It is because of a manufacturing defect in the shingle (not fixable)
4. It was installed over existing shingles (not fixable)
5. There is insufficient ventilation of the attic structure (easy to fix, but mostly likely it will be too late for that roof covering)
Insufficient Attic Ventilation
Let focus on #5 on that list. Most people don’t realize how important having the proper attic ventilation is for a building and its materials. You want your attic to be as close to the outside ambient temperature as possible and the way to achieve that is with ventilation. I will go into much greater detail about the different types of attic ventilation (mechanical vs passive), how to calculate the amount of ventilation needed, and the common issues with each type in a future blog, the point of today’s blog is to show an EXTREME example of why it matters. I commonly see poorly ventilated attics and they most often have shingles that are prematurely curling but that’s in years 7-12, this roof WAS JUST 3 YEARS AND 4 MONTHS OLD!!!
Once I got inside the attic it took less than a minute to confirm my suspicions as to why this roof looked this way. Two simple mistakes were made by two different trades. The roofers had covered the ridge vent cutout with the roofing underlayment and DID NOT spend the 3-5 minutes to take a razor knife and cut it out before properly installing the ridge vent cap and shingles. They had sealed off the exhaust portion of the ventilation system. Second, the insulation contractor had blown in Fiberglass insulation all the way to the roof decking at the eaves. This blocks the soffits (intake air) and prevents fresh air from entering the attic structure. Given the height of the attic space and essentially being sealed from outside air I can not begin to imagine hot that attic is throughout the summer months but its effects are quite obvious.
Always hire a Home Inspector
This house is also a great example as to why home owners should always hire an experienced home inspector after major projects are done on the home. The seller was quite upset to learn that a roof they spent $8,100.00 just 3 years and 4 months ago needs to be replaced because of 2 mistakes that should have never happened.