15 Causes Of Roof Leaks

There are many reasons as to why you may have a roof leak and it can be daunting to know where to begin to find out where the leak is coming from and why it is happening.

In this guide we have outlined the 15 most common causes of roof leaks.

15 Causes Of Roof Leaks

11 Roof Defects That Cause Water Leaks

To fix a roof leak you have to find it first. Sometimes finding the leak yourself can be harder than actually fixing the leak. To complicate things even more the actual source of the leak can be a long way away from the location that unwanted water is found.

There are some leak detection methods that you can try yourself like the hose pipe test where you soak sections of your roof with a hose pipe to see where water is entering your roof but sometimes these self tests don’t come up with any definitive answers and this is when instructing the help of a leak detection specialist such as ADI Leak Detection, we utilise high tech roof leak detection methods to efficiently find your leak.

Poor Quality Dry Verges

Dry verges are a roofing system that interlock and clip over the edge of roof tiles helping to keep them secured in place and preventing water and pests from entering your home.

If the dry verges on your roof are of poor quality they won’t offer the longevity you would expect and will begin to fail and allow water to enter into your property.

If you have had dry verges fitted onto your existing roof it is important for your roofers to install it correctly and remove the existing mortar before installation as overtime the remaining mortar will begin to crack and allow water underneath the new dry verges causing roof leaks. 

Missing Or Cracked Roof Verge Pointing

If your properties roof verge pointing is missing or cracked it is inevitable that water will be allowed into your home and cause damage. Roof verge pointing is the gap between the edge of the slates and the top of the brickwork.

This gap is usually filled with cement mortar which can crack and fall away with time. So it’s important to regularly check the condition of your roof verge pointing and have it repaired if it starts to crumble away. 

Verge of house roof with crack
Valley on house roof with crack

Missing Or Cracked Valley Pointing

Roof valleys are the channels where two roof slopes meet, they collect rainwater and allow it to flow towards the gutters away from the roof.

If the roof valley pointing is cracked or missing there will be an exposed entrance for water to flow into before it reaches your gutters. This water will seep through your roof material and into your loft where it will start to create damp and mould which can weaken the structure of your home.

It is important that the correct materials are used for your roof valleys to ensure your roof stays waterproof for longer.

Cracked Ridge Tiles Or Missing Ridge Pointing

If you have cracked or missing ridge pointing your roof will definitely spring a leak when it rains. Ridge tiles are the tiles that run along the top point of your roof joining each side of the roof together and the ridge pointing is what holds these tiles in place, usually cement is used to secure the tiles.

The ridge pointing can become damaged with age and from repeated bad weather. Even if there are no missing ridge tiles on your roof or there are no visible cracks in the tiles there can be very fine cracks that form in the pointing which will allow water into your home.

Over time these cracks will get bigger allowing even more water to enter and cause damage to the surrounding tiles making the repair job even bigger. 

House roof with Missing pointing between ridge tiles
house roof, chimney with half missing flashing

Damaged, Cracked Or Missing Roof Flashings

Flashing is vital for a well protected roof, flashings are installed along the joints of the roof as well as around anything that protrudes from the roof like chimneys and roof vents to seal off these weaker points of the roof which otherwise would allow water to leak into your property.

If these flashings become cracked or damaged you will end up with a roof leak which has the potential to cause some serious issues. Flashings can become damaged or cracked due to environmental impacts like temperature changes or by general age related wear and tear. 

Chimney Cracks

A cracked or damaged chimney can cause devastating damage to your property. Over time your chimney will experience repeated exposure to harsh weather which can cause the mortar that holds the chimney together to wear away offering places for water to enter your roof.

The most common place to experience a leak from your chimney is the chimney cap or the mortar near the top of the chimney.

If these both seem to be intact then another good place to look for where the water is entering is the flashing around the base of the chimney. If this is damaged it offers a great place for water to seep into your roof. 

House chimney with crack allowing water ingress
House with a missing roof tiles

Broken Or Missing Roof Tiles Or Slates

Roof tiles and slates are the primary mode of protection to keep water from leaking into your roof. It can take just one missing or broken roof tile or slate to cause a roof leak and cause lots of damage to your property.

If you notice roof tiles or chips of tiles in your garden after high winds it’s a good idea to check if they have come from your roof. The longer a roof tile is missing from your roof the more water will enter your property and the more damage and expense iit will cause.

So it’s a very good idea to replace any missing or damaged tiles or slates as soon as you notice them. 

Damaged Roof Underlay Or Membrane

The underlay or membrane sits underneath your roof tiles and if the roof tiles become cracked or fall off the roof this underlay or membrane will be exposed to the elements.

They are designed to be able to withstand a small amount of moisture but prolonged exposure to rain will eventually rot away the underlay or membrane or cause rips and tears which will allow water into your property whenever it rains. 

inside a loft with roof memebrane hanging down
Roof Vent with leak

Incorrectly Installed Roof Vents

Roof vents allow warm air and moisture to escape from your roof to help minimise the risk of condensation build up in your loft.

If the roof vent or the flashing around the roof vent has been incorrectly installed it will allow water to leak into your loft space whenever it rains.

A good indicator that your roof vent is leaking is to have a look under where the roof vent sits and if you find dark spots it means moisture has got its way in. 

Incorrectly Installed Skylights Or Roof Windows

Incorrectly installed skylights or roof windows will undoubtedly result in a roof leak. Luckily these types of roof leaks can be the easiest to detect.

It’s important to note where the leak is around the skylight or roof window though as if the leak is at the top of the window this could indicate that the flashing around it has failed or has become damaged.

Aside from damage from an impact like a fallen tree hitting the skylight or roof window or age related wear and tear a leaking skylight is often caused by improper installation. 

Roof Skylight with leak
Roof Window with leak around edge (not sealed correctly)

Incorrect Fixings Or Incorrectly Used Fixings

If incorrect roof fixings are installed on your roof or the fixings are installed incorrectly they can have a devastating impact on your roof and home.

It’s vital that the correct fixings are used when your roof is built and when any repairs are undertaken as if incorrect fixings are used the lifespan of your roof will diminish very quickly.

You could even experience a roof collapse, which could not only be a massive expense to fix someone could get seriously injured or killed in the event of a collapse. 

4 Environmental Causes Of Roof Leaks

If you are struggling to locate the source of your leaking roof you may wonder who does leak detection? Luckily for you ADI Leak Detection is the UKs first leak detection service that specialise on finding any type of leak in or around your property.

We use state of the art specialist technology to pinpoint the location of the leak with high efficiency and accuracy. 

Roof Deterioration With Age

Old english cottage with a clay tiles roof

Like most things in life, roofs don’t last forever. Over time the materials used to build your roof reach the end of their lifespan.

Most roof tiles are designed and made to last for decades but eventually the level of protection they can provide will decrease and make them more prone to allowing water into your home. Your roof will become worn overtime by extreme temperatures and bad weather.

Keeping your roof properly maintained will help extend the lifespan of your roof and tiles, it is advisable to regularly have your roof cleaned to remove moss buildup which can grow under the roof tiles causing them to light and even fall off your roof. 

Overflowing Or Blocked Gutters

Blocked or overflowing gutters will cause them to not function properly and can be a big cause of roof leaks. As the gutters fill up with debris such as leaves from nearby trees and moss that has grown on your roof they become clogged and are unable to carry the rainwater that falls onto your roof away effectively.

As this water collects it can begin to pool and can start to enter your roof where cracks and weak spots are. It is important to inspect your properties guttering regularly and especially in spring and winter when they are more likely to get clogged up with fallen leaves and twigs.

Sometimes you can identify a clogged gutter from the ground as you may be able to see small branches and leaves piling up and hanging over your gutter. If you suspect your gutter is full its important to have them cleaned out quickly as maintaining a fully functioning gutter system is vital for the overall health of your home. 

Overhanging Tree Damage

house, with tree, branch overhanging and tree debris laid on the house roof

While trees are an essential part of life, trees that overhang your roof risk causing damage which will lead to roof leaks. Particularly in the autumn and winter if branches have been falling onto your roof they could be chipping away at your roof tiles.

Even the smallest of cracks to one roof tile can give rainwater the opportunity to enter your roof space and cause damage. Leaves that fall on your roof will find their way into your gutters causing them to become blocked and overflow.

Birds that nest or sit on in the tree can cause a build up of bird poo on your roof and the acids in the poo can attack the surface of your roof tiles causing them to break. It’s a good idea to prune the trees around your property to prevent them from causing damage to your roof. 

Damage Caused By Men Working On Your Roof

man walking on house roof

If you have recently had work men up on your roof and notice you now have a roof leak the weight of the men could have caused damage to your roof which is now allowing water to leak in.

Roofing materials are designed and crafted to be very resilient to whatever mother nature throws at them but they are not designed to withstand the weight of a human being.

Therefore if you yourself or a workman has to gain access to the roof it’s important that caution is taken when putting weight in the roof as walking on the roof can easily cause roof tiles to crack and break creating an entrance for water to enter your roof. 


If you find you have damp areas in your loft this could be due to a leaking roof or it could be condensation.

Condensation occurs when warm air meets a cold surface, as warm air rises there can be a higher concentration of warm air in your loft then elsewhere in your home and as the temperature outside can be low the materials in your loft becomes cooler making a perfect environment for condensation to occur. If you start to notice a damp musty smell coming from your attic it’s a good idea to head up there to investigate.

It can be difficult to work out whether the dampness in your loft is due to a roof leak or condensation but there are a few things to look out for which are outlined in our roof leak vs condensation guide. 

Are roof leaks covered by homeowners insurance?

Yes, as long as a few criteria are met. For instance, the cause of the leak needs to be from extreme weather like a storm, or even a fallen tree that has hit your roof.

Your homeowners insurance will not cover the damage caused by roof leaks if the leak has occurred due to the roof being old or  not well maintained.

Even if your roof has been damaged by a storm but  your insurance company deems that before the storm the roof was in disrepair and poorly maintained they will not cover you.

It’s very important to look after your roof, check it for damage regularly and keep a record of any work or maintenance you have had carried out on your roof such as receipts of work to show your homeowners insurance company you have kept your roof well maintained incase of any leaks.

Sometimes you don’t need specialist equipment to find out where your roof is leaking if it is an obvious cause. But other times the source of the leaking roof is less obvious and the use of specialist equipment is needed in order to pinpoint the leak quickly.

Also the use of specialist equipment enables the leak detector to find the leak without having to tear into walls and ceilings helping keep cost and destruction to a minimum. So if you ever wonder how to find where your roof is leaking look no further than ADI Leak Detection!

Call ADI Leak Detection To Find The Source Of Your Roof Leak

If you are currently facing a roof leak and are struggling to find the cause call ADI Leak Detection today to get to the root cause of the problem.

Our specialist will help prevent further damage from happening to your property, locating the source of the roof leak and creating a detailed report as part of every investigation.

We have specialist engineers located all over the UK who are happy to help all leaking roof emergencies. 

Call Now On 0800 731 3843

ADI Leak Detection Customer Service Office Team

Adrian Morgan

Adrian Morgan CIPHE RP RHP is the founder & Managing Director of ADI Pro Leak Ltd. Adrian is also the Head Plumbing, Heating & Leak Detection engineer at ADI Leak Detection.

Adrian CIPHE RP RHP is proud to be registered with the Chartered Institute of Plumbing & Heating Engineering, a Registered Plumber and a Registered Heating Professional.