Why Is My Metal Roof Leaking?

Why Is My Metal Roof Leaking?

metal roof leak repair professionals

Metal roofs are vulnerable to trapping excessive moisture and damage from heavy rain or wind. Since individual panels are attached to metal or wood trusses with steel nails, these are prone to rust and thus may allow for leaks. Furthermore, strong winds have the ability to separate any overlapping edges of the metal roof’s panels, thus opening gaps for leaks.

Is metal roofs right for your building? What can you do to safeguard against water penetration? If you are keen to find the answers to these questions, then this article is for you. We have written this article as an overview of metal roofs, in particular its interactions with water.

The Advantages and Disadvantages of Metal Roofs

The advantages of metal roofs are as follows:

  • Longevity: stemming from its ability to last around 40 to 70 years.
  • Durability: metal roofs are impact resistant, keeping your building’s inhabitants safe from any debris.
  • Safety: metal roofs are resistant against sparks and catching fire.
  • Energy efficiency: metal roofs will reflect solar radiant heat, thus helping you to save cooling energy costs by 10 to 25%.
  • Environmentally friendly: metal roofs contain a high percentage of materials that are recyclable.

The disadvantages of metal roofs are as follows:

  • Affordability: metal roofs can cost as much as 2 to 3 times more than other roof types. However, in return, you can expect a significant lifespan.
  • Noise: metal roofs can be very noisy to its inhabitants especially during a heavy rain storm. To overcome which, additional insulation can be added.
  • Prone to expansion and contraction: more so than other materials, metal roof panels tend to expand and contract. Over time, this creates gaps when panels loosen, thus exposing the roof to water penetration.
  • Vulnerable to water penetration: should water accumulate anywhere on your metal roof, seepage is likely to occur since metal roofs tend to be thinner and easier to penetrate.

General Metal Roof Problems

There are four general problems that metal roofs run into – (1) roof leaks, (2) blow offs, (3) punctures & tears and (4) ponding.


Roof leaks are a common problems that homeowners face with metal roofs. For example, poor workmanship in the initial installation phase may have resulted in both gaps and punctures in the roof. Such openings allow for water to leak through over time.

Blow-offs also occur due to poor installation. When the flashing is not properly attached, the resulting open seams and laps provide insufficient support for the roofing, thus allowing to be blown off when face with heavy winds.

Metal roofs are also vulnerable to punctures or tears. Typically, this occurs due to excessive human traffic on the roof or from heavy debris that land on the roof due to a storm. It is advised that minimal weight and stress be placed on metal roofs since they are thinner than most.

Ponding refers to the situation whereby water accumulates on your roof. When ponding occurs, excessive pressure is placed on the roof since it carries the pond’s weight. Moreover, ponding weakens any waterproofing systems and allows for moisture to slowly creep past the surface.

metal roof damaged

Why do Metal Roofs Leak

As with most other roof materials, metal roofs are most vulnerable to water leakages during rainy season or a heavy storm. During such times, not only is the roof exposed to more rainwater and hasher winds, but water is given the ability to find the aforementioned gaps that metal roofs tend to have.

Typically, roofs have a designated exit path for rainwater to take. This path reduces the exposure that roofs have to large quantities of water at any one time. Moreover, it guides water away from areas of weakness on the roof. However, when wind is strong enough, rainwater no longer solely flows downhill. Instead, wind can blow water along the entire surface of the roof, pushing it under flashings and down between metal joins & seams.

Common areas for water seepage include those of HVAC, piping & solar installation. When these features are installed on your of, dozens or roof penetrations are required, making them especially vulnerable to water intrusion.

Additionally, depending on the setup of your metal roof, capillary action may also naturally draw water sideways or upwards. This further allows water to find even the smallest of gaps, ingressing under and along the underside of your roof.

Following the entry, water is capable of travelling surprising large distances following a path of least resistance. This makes tracking and finding the original location of entry highly difficult. Over time, water tends to accumulate in a few hidden and vulnerable areas within your house’s structure. It is in these areas that water damage will be most prominently found.

How to Waterproof Your Metal Roof

Traditionally, paints, coatings and sealants were used to provide resistance to water penetration. However, by themselves, these materials are poor long term waterproofing solutions. Sealants which provided the primary form of protection, are vulnerable to the sun’s ultraviolet rays, oxidation and cracking. As such, their deterioration rates required homeowners to engage in frequent reapplications.

Instead of paints, coatings and sealants, homeowners should strongly consider hiring waterproofing specialist contractors to apply waterproofing membranes. A fundamental component of modern metal roof waterproofing, a waterproofing membrane is a permeant coating that is UV, pollution, salt and chemical resistant material that prevents water ingress. It is highly robust and provides a long term waterproofing solution for your metal roof.

In particular, liquid based waterproofing membranes can be used to seal areas around external roof installations. These give roof modifications a water tight and structural robust membrane that lasts for a long time.

metal roof waterproofing membrane

Choose ProSeal Contracts for Your Flat Roof Waterproofing Needs

ProSeal Contracts is a waterproofing company in Singapore with more than 20 years’ experience. As one of the leading waterproofing contractor companies, we use the highest quality of materials to ensure long lasting results. Trust us to assess, choose and apply the right waterproofing procedures for your building’s needs.

Our waterproofing methodology for a RC Flat roof is a 5 coats that ensures years of protection against water leakages. Additionally, it insulates against deterioration from carbonation, acid or chemical attack

Find out more about our metal roof leak repair services.

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