How To Detect Leaks In Your Roof


Your home’s roof is the first main defense against water ingress and damp. When leaks occur, they tend to manifest in a number of different ways. Often, where damp occurs doesn’t strictly fit in to where the physical water ingress is.

However, if you take your time you can often track down a problem and either repair the damage yourself, or let a local roofer know what you’ve found.

Here are some ways to track down those annoying leaks!

High Level Damp on Internal Walls

This normally occurs because of condensation traveling within the air of your home. All homes have a small amount of moisture within them caused by leaks, cooking, showering or drying clothes. This airborne moisture will travel to a cold part of the home, such as a window or wall that’s exposed to the elements. Here it condenses back into water and begins to cause damp.

Quite often this damp isn’t actually caused by a leak, but rather moisture created within the home. A dehumidifier is a great step to lower the overall moisture level but the simple act of opening windows can help bring fresh and dry air into your home too.

Water Running Down The Sides of External Walls

This is usually caused by a blocked gutter or faulty seal between a joint. Leaks like this don’t often cause damp straight away, it usually takes time for the water to penetrate the wall and get to the inside. Most modern homes also have a cavity wall, which will mitigate this happening; however, many homes built before 1930 will have a thick single skin wall that makes this type of damp a particular issue.

Perished Roof Felt

Roof felt is a membrane that roofers install underneath the tiles of your home. The idea is that 99% of all the water that your roof deals with is shed by the roof tiles, whilst the remaining portion runs under the tiles on the waterproof felt.

Most of the felt on your roof is protected by the tiles, so although they may deal with a small amount of water they never see sunlight or the outside World. However, there’s always a small section of felt that’s used as a bridge to safely drop any water safely into your gutters.

One of the issues that can happen, is that this exposed felt perishes over time and eventually leaks. This can cause what looks similar to a leaky gutter, except the water will spill over the inside of the gutter closest to the fascia. Occasionally, some water will actually flow back into the property, where it starts to cause leaks on the wall closest to the affected roof line.

If you’re handy with a ladder, you can check this yourself or employ a competent roofer or gutter repair professional.


Many older homes have a dedicated chimney installed, particularly older terraced houses. These chimneys can now be over 100 years old and deal with everything the weather brings to them.

For the most part, leaks caused by chimneys are caused by lead flashing that’s fallen out of place. This caused water to creep into loft spaces and flow down to the living areas of your home. To check for these types of leaks it’s always best to go into your attic and look around the chimney stack to see if there are signs of damp or water marks.

Cracked or Slipped Tiles

These are the easiest leaks to spot, as slipped tiles can often be spotted at ground level. Thankfully the repair to a slipped or damaged tile is something a competent roofer can tackling without too much expense.


The main takeaway with leaking roofs, is to take your time and inspect as many parts of your roof as your can. Quite often leaks are detected with trial and error, especially on older properties where multiple issues could be the root cause.