Several defects are prone to create and cause roof problems during its span and the identification of such issues should not be a difficult task for contractors. The underlying comprehension of some of the most common defects in roofs, as well as their possible location, can help to more easily identify and remedy many of the more obvious problems.

Here are 8 of the more common major defects found within roofing systems as well as some of the top rated measures used to help prevent or repair them.

1. Wind Defects

More wind prone areas of the country are subjected to upward pressure that blows from beneath the roof edges in an upward fashion. This tends to rip up the membrane, break the seals, and cause damage to shingles themselves. Strong wind driven storms or hail can make these effects more pronounced.

While a lot of types of damage is not preventable there are still steps any roofer can take to help prevent this from happening. One recommendation is that installation occurs according to strict manufacturers instructions and that no steps are skipped in the application. Many different types of shingles have different ways of attaching and some of the more prominent rules pertain to installation within windier parts of the country.
Here, additional fasteners (often times 6 as opposed to 4) will be used to secure the roof.
Special attention will be given towards the sides, bottoms as well as the ridges.
Additional factors such as appropriate drip edge and flashing will also help to keep the substrate dry and protected.

Hail damage  

Wind Damage


Proper high wind installation 


2. Weathering

Organic or not?

The roof material used can be either organic or inorganic in nature.
Organic roofs can become easily deteriorated due to weathering action in comparison to inorganic roofs. The rate of deterioration increases if the atmosphere is concentrated with pollutants or industrial effluence. In addition, Heat or High Winds will also decrease the length of time that any organic roof will last. During Hurricane Florence in 2018, I was able to see first hand damage of this occurrence within my own neighborhood in Wilmington, NC. The Builder had used a new type of organic “bio-degradable” materials that would be better for the environment. This was supposed to be a 30-40 year shingle. Imagine the surprise to all homeowners that then had to replace their roofs after just 11 years!!

Some tips to prevent weathering of roofs are:

+ Inspection of roofs once or twice a year.

Knowledge is key and if you know of something that is preventable – like trees overhanging (and thus dropping more branches and leaves on top), or branches actually scratching and damaging the rooftop area, annual trimming should be the minimum requirement.
For the most part trees should not be this close to the home for other reasons, to include the root systems potentially impacting the earth beneath the foundation.

+ Providing for more adequate ventilation

This much is required for both Hot and Cold or conditions where both can occur within a given year. Roofs are like people in that we need to breathe and have the ability to keep warm or cool… but not too cool.
Better insulation and ventilation will help to create a good environment for the maximum lifetime of any roofing system.

Insulation pertains to the amount used in attics. Typically more is better – but only up to a certain depth. Most are good with 24 – 30 inches of blown cellulose insulation.
Ventilation occurs better with sufficient Ridge and Soffit “flow-through” ventilation.
For more extreme cases a thermostatically operated attic fan can easily keep higher temps cooler on days where more extremes of heat exists.


3. Improper Design and Maintenance

Flat or low-sloped roof demands higher maintenance costs as it tends to collect more sediments and water that eventually destroy the roofing material. Routine (at least annual) cleaning and maintenance checks for buildings with more flat or sloped roofs will help to ensure that this does not occur.

Roof defects caused due to improper design are comparatively difficult to fix. Such defects can be corrected by replacing the roofing materials. Some of the common mistakes performed in roof design are:

Improper roof slope, drainage, and sagging roof, resulting in water accumulation and deterioration of the roofing material.
There is no proper design system to allow expansion and contraction of the deck material.
The structure supporting the roof system is weak and deflects due to active loads.
The use of incompatible roof materials.

4. Improper or no Base Flashing or Drip Edge Flashing

Base flashing is performed at the joint between the surface of the roof and a vertical surface to guard against water penetration. Some common base flashing issues that cause defects in roofs are:

Insufficient coating or height of the base flashing
Incorrect fastening to the surface or Poor adhesion – Must be properly adhered to the roof surface to prevent leakage.
Loose insulation below


5. Improper Flashing Material and Procedures used

The purpose of the flashing any roof is to better seal the sections that are flashed and prevent water from entering any parts of the structure itself. Incorrect flashing procedures results in the penetration of water between the roof systems and the roof structure. Early flashing defects must be further sealed to prevent any chance of future defects.

The following contains a more detailed explanation to flashing and its importance.


6. Improper Drain Flashing

A good drain system requires a sufficient amount of drain openings. The drain flashing process is not as easy as constructing drain openings. Overflow scuppers prevent the accumulation of water during an emergency or heavy rain. The collection of water around the openings (from leaf or branch accumulation or other forms of damage) can cause moisture damage to the roofs.


7. Faulty Penetration or Metal Base Flashings

Some issues with penetration flashing that can create certain roof defects are:

Improper design work – if the unit is not designed appropriately, it does not matter how good the install was – it will leak.
Improper finishing of the metal surfaces. Certain types of metal are not meant to be exposed, others are. It is important to know which is which and ensure that it is installed according to design specs.
A deteriorated counter – this typically occurs due to excessive rust and or

Damage to roofs due to standing water behind the penetration curbs.

Penetration flashing must be properly held to the roof to prevent any leakage and clogging of water.

Metal base flashing defects are commonly observed in the bituminous (flat) roof system. The metal flashing material and bitumen have high contraction and expansion rate that creates cracks and openings. This leads to further water penetration and damages to the roof surface. It is hence recommended to use a bituminous flashing for a bituminous roofing system.

Degradation should also be looked at when view certain pieces of metallic base flashing material as oxygen, sunlight and certain metals are especially prone to rust and deterioration.

8. Rooftop Equipment

Rooftop equipment like solar panels, satellite antenna, A/C compressor, etc should not be directly placed over the roof surface. A support structure can be constructed over the roof membrane to carry the equipment. When equipment is mounted through the roof, it creates holes and openings that will then at least need to be maintained with a temporary silicone protectant – which again is temporary at best, and must be checked annually for signs of wear and need for replacement.


Roof problems are mainly caused due to:
1. Damage of roof due to wind action
2. Weathering defects of roofs
3. Improper design and or maintenance of the roof system
4. Improper Base flashing
5. Improper Flashing Material and Procedures used
6. Improper Drain Flashing
7. Faulty Penetration or Metal Base Flashings
8. Rooftop Equipment

In addition there are many other aspects to a roof design that are able to either sufficiently protect OR create failures within any roofing system. These failures can be immediate, although most will take some time for the problem to develop. Over time, defects become tend to become greater and greater, and as a result the cost of repair climbs as well. Therefore, the best counsel given is to keep up with repairs just as soon as they are made known. I have yet to meet anyone that has saved any money or headache by waiting for a repair to become worse prior to resolving.
Homes are almost always in need of a more organized system of checks and balances to ensure that repairs are made when they are truly needed in order to keep maintenance costs to a minimum all while ensuring years of happiness and comfort will be forthcoming.