Discovering you have a leaky roof can be a stressful experience, but sometimes determining the source of the leak can be an even greater challenge. This is because the origin of the leak rarely matches where the leak appears on the inside of the home.
While every leaky roof situation is different, there are some common causes of a leaking roof that can provide a good starting point for your investigations. Check out the 10 most common causes of roof leaks below.
1. Eroded Sealant
Anywhere there are joins between different roofing materials, you will find sealant. It is used to provide a waterproof seal around skylights, vents, joints, chimneys, screws and guttering.
Sealant is the weakest point of your roofing system; it is not as durable as roofing iron or tiles and will erode more rapidly over time. Sealant can also become dislodged and break its seal if there is movement in the roof system. Checking the sealant around anything that has made a hole in the roofing material is the first thing to look at when seeking the source of a roof leak.
2. Clogged Gutters
Gutters are designed to carry water away from the roof system preventing it from getting into places it shouldn’t. If your gutters are blocked, this will cause water to pool, and it will have more of an opportunity to seep into the structure of the home.
If you can see leaves or grass sticking out of the gutter or should you notice a lack of water coming out of a downspout during heavy rain, these are good signs you need to clean out your gutters.
3. Damaged Flashing
Flashing are thin pieces of sheet metal that are installed at the joints of your roof and around the edges to create a water-resistant barrier where the main roofing material cannot. Although flashing does its job well – it is considered a weak point in the roofing system due to the number of joins required during installation and its positioning.
Flashing in the valleys of the roof are the most vulnerable to leaks as valley joins process the water run-off from the roof and are prone to blockages and unseen pooling water. However, flashing along ridges and edges are also notable for their constant exposure to the elements and overlapping nature.
4. Failure Of Underlay
While your roofing iron and tiles are designed to keep water out, there is always the possibility that water can travel into cracks and gaps and the likelihood of condensation build-up at times. The roof underlay is designed to provide a secondary layer of protection against this moisture entering the home.
The roofing underlay or moisture barrier is installed under the main roofing material and allows any moisture to run down to the edges of the roof and into the gutter. See here for more information from the BRANZ on roofing underlay requirements in NZ.
5. Broken Or Dislodged Roof Tiles
If you have a concrete tiled roof, it is possible for tiles to be dislodged and move out of place during extreme weather conditions or decay from age. Tiles that have cracked or moved even a small amount are a very common cause of roof leaks and can lead to significant damage to the interior of your home when left unnoticed.
A tiled roof requires regular checks to maintain its integrity; any broken or cracked tiles need to be replaced, along with continual checks of the internal roof space for any signs of dampness or unexplained water stains. In areas of New Zealand where snowfall occurs, it is important to thoroughly examine roofing tiles after the snow melts.
6. Rust And Corrosion
Roof rust and corrosion occurs gradually over time when metal roofing comes into contact with moisture, causing a chemical reaction. This reaction means the metal is breaking down very slowly and is prone to developing holes and gradual leaks.
In New Zealand, rust in the roofing iron is most prevalent in older homes as roofing iron these days is always galvanised (a process of applying a protective zinc coating). However, a metal roof can still exhibit signs of rust over time as the material is continually exposed to the elements. Homes in coastal or high-rainfall areas are particularly prone to rust due to the combination of salt and moisture in the air.
7. Vent Booting Failure
Usually made from rubber or plastic, vent boots are used to cover any protrusions from the roof, such as toilet vents, kitchen vents and chimneys. Vents boots slide over the pipes or chimney to work in combination with flashing and sealant to provide a flexible waterproof junction between the two materials.
As with sealant, vent booting is not as durable as roofing iron or tiles and will slowly degrade over time. If a leak from vent booting is suspected, it is best to replace the entire boot and reseal.
8. Complex Roof Architecture
While your home may be an architect’s dream design, complex rooflines can be challenging when it comes to leaky roofs. Even when well maintained, the increased number of valleys, slopes, ridges and joins can be problematic, particularly as the years progress and especially if they are not properly installed to begin with.
If you have a complex roof, regular roof checks are simply a must. Discovering you have a leak that has gone unnoticed will mean the likelihood of very costly repairs.
9. Chimney Erosion
No matter what your chimney is constructed of or where it is situated, the chimney is one of the most likely places for a leak in the roof. This is because it requires a large hole in the roofing material and is often surrounded by several different waterproofing materials, including but not limited to flashing, mortar, bricks, sealant, and/or a rubber chimney boot.
Water can trickle and pool in places that you may not even imagine when there are this many different components involved. Chimney checks should always be carried out at least twice a year or more if your chimney is surrounded by aging bricks and mortar.
10. Unexpected Damage
Of course, you can’t keep an eye on your roof every single day; holes and cracks can unexpectedly occur caused by falling branches, movement in the roofs fixing systems, storm damage or even the local animal population such as cats and possums.
Sometimes damage can even be caused by walking on the roof when carrying out roof inspections or repairs. Holes in your roof are the most obvious cause of leaks and can usually be spotted on closer inspection; if you find a hole in your roof, it is always best to consult a professional roofer as substandard repairs are only going to cost you money in the long run if they fail.
If you suspect you have an issue with a leaky roof, you should seek to complete repairs immediately to prevent further damage to your home. Action Reroofing are professional reroofing specialists serving the greater Christchurch area. We can help you determine the cause of your leak and find the best solution fast. Call Action Reroofing for an extensive roof inspection, roof leak repairs or full roof replacement today. Catching a leak early saves you time and money!
