what roof style is most prone to leakage

Which Roof Style is Most Prone to Leakage?

Water damage on your ceiling or walls indicates something is amiss in the attic space, signalling a leaky roof is likely a serious issue and that immediate action must be taken in order to address it before it gets any worse.

Many factors contribute to the deterioration of roofs. Age-related wear and tear, storm damage and blocked gutters are among those most frequently responsible. If you need any support, you can contact licensed roofers to help you.

Flat Roofs

Flat roofs are notoriously vulnerable to leakage due to poor design and structural integrity issues, particularly on older buildings where flat roofs may not have had time to evolve over the decades.

Flat roofs can also be affected by temperature variations that cause them to move, leading to membrane delamination and premature leaks on your roof.

Poor drainage exacerbates this problem, leaving water to pool on your roof instead of draining away quickly and effectively.

There are ways you can prevent this from happening. By performing regular inspections and maintenance checks, any issues will be detected early.


Valleys are areas where two roof planes meet to form a low point in your home, creating an area with the greatest risk for leakage due to water’s continual flow from roof top to valley and its potential damage caused if not sealed properly.

In order to avoid leaks in roof valleys, it’s crucial to select an appropriate material to line them. This choice depends on whether your roof features an open or closed valley and what kind of shingles make up its surface area. If the worst was to happen, you should contact an emergency roofer to help you.

Closed valleys require an ice and water shield before covering with shingles, which serves to protect the roof decking should any moisture get beneath the shingles in the valley. Open valleys require metal flashing – which may prove more complex as you must transition your roofing materials into the metal flashing you install in the valley – yet ultimately this option provides better protection.

Stack Flashings

Stack flashings are rubber “boots” placed over pipes and vents on metal roofs to seal them against water penetration and prevent leakage. As their lifespan is typically shorter than that of their roof itself, this area often leaks.

Flashings typically consist of rubberized material that sits flat on a metal roof to form a seal and also wraps tightly around pipes for added seals. As metal roofs expand and contract over time, their movement puts tremendous strain on these seals if they’re not regularly replaced as necessary.

Zinc, aluminium, copper and lead flashings are popular options when it comes to flashings for roof pipes or vents on your roof, providing waterproof seals against rain, wind and snow from entering.


Penetrations can occur easily on roof membranes in poor condition, and water can find its way inside if left undeterred by deflectors built into modern roofing membranes that help divert it away.

A key way to prevent leakage on a rooftop and structure is through regular inspections, especially of penetration areas.

Simply stated, roofs with high concentrations of structural components such as HVAC units or drains require strong and resilient roofing membranes for protection.

Real estate enthusiasts will know that penetrations are measured in square feet. They encompass any and all openings such as stairs, fire towers, vents or pipes that may come through roof surfaces – the roofs with the most penetrable surfaces also being more likely to experience leakage issues.

In roofing terms, this means an area that breaks through the roof membrane and must be “flashed” to make it watertight. This includes a range of structures that penetrate through the roof, including plumbing vents, HVAC blocks, metal pipes, and more.

During construction, penetrations are usually sealed using field wraps, pipe boots or pitch pans. These products protect them from moisture and prevent leaks. They should be replaced as necessary when the materials wear out or break down, and flashing is often recommended when they do.

For example, a roofer may install flashing when installing flat roofing material for a minimal slope to close the spaces between the plastic vent pipes that protrude from the roof surface. Once the roof is complete, the gaps between the flashing and the penetrations are filled with caulk or waterproof cement to prevent water from entering.

However, in some cases, the roofer doesn’t provide adequate protection for the areas he’s working on, which can result in leaks. These types of areas include valleys (the internal angle formed when two planes of a roof intersect), ridges, chimney walls and skylights.

Since the roofing materials that these areas are protected with are meant to last for many years, they must also be durable and weather resistant.

Read our other article: Why Do I Have Damp Patches on My Ceiling After Heavy Rain?

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