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How to Check If You Have a Leaky Roof

John is an experienced freelance content writer with an eclectic employment history.

Water is an insidious beast. We rarely think about how dangerous it can be outside the context of a swimming pool or the ocean, or a flooding in our home, but the truth is you can drown in an inch of water—and a minor leak can do a significant amount of damage to your home if left to its own devices.

Given the nature of how our homes are usually built, leaks will often come from one of two sources: faulty plumbing or your roof. Now, you may think it should be obvious which is which. After all, the roof is above you, and the pipes are in the walls, right? Well, not exactly. As we’ll get into below, your pipes can be (and probably are) above you, and water from a leaking roof won’t necessarily be visible as a patch on your ceiling.

Water getting into places it shouldn’t in your home can have a range of effects that can be relatively minor—like wallpaper losing its grip on the wall—or pretty serious—like black mould developing. It can cause issues with electrical systems, deteriorate wood, and generally look unsightly. In short, you want to take care of a problem like a leaking roof at the earliest opportunity.

The Unseen Problems of a Leaky Roof

If you have a spreading damp patch on your ceiling, or a sanity-sapping dripping noise that never stops, the signs of a leak are pretty obvious, but there is more to this problem than what you can see.

For example, most types of insulation found in typical loft react badly to moisture, and will lose their insulating properties if they get wet. Certain types of loft insulation will also turn into a breeding ground for mould once they get wet—far more than a regular surface, like a wall or ceiling.

Of course, there is also the threat to the electrical systems in your house. Electrical wiring and installations are required to be installed to a particular standard precisely to ensure everything is safe, but typical home or business electrical systems are not designed to get wet, and won’t react well if they do. For the most part, you should be safe, as your fuse board should cut out the very instant an electrical connection is shorted. But you will still be left with electrical systems cutting out, and just because the safety precautions are there doesn’t mean they need to be used.

With a roof leak, water can get into your wall and floor cavities, where it could affect your home's electrical systems.

With a roof leak, water can get into your wall and floor cavities, where it could affect your home's electrical systems.

Identifying a Leaking Roof

As I mentioned earlier, your home almost certainly has water pipes going along a ceiling somewhere. It may be an immersion heater in the loft, it may just be the pipes for an upstairs bathroom. If one of those pipes were to leak, it could look like a roof leak from below.

Similarly, your home is not just a simple box made of brick. There are cavities for insulation, not to mention all sorts of quirks and twists in the architecture. It is entirely possible that your roof could be leaking, and the water manages to run all the way down the inside of your walls, perhaps showing as a damp patch downstairs. In that situation, would you suspect a leaking roof?

Water on the Ceiling

This would typically be the most obvious sign that there’s a leak in your roof, but it’s not guaranteed to be from the roof. As I’ve mentioned, you could have pipes up there that are leaking, and if it’s a downstairs ceiling, it could be coming from something upstairs. The easiest way to check is to head upstairs—or into the loft—and try and find the source. If you get above the water patch on your ceiling and there’s no leak, it’s probably coming from between the floors.

Sagging Ceilings

The chances of getting this far without noticing the water are pretty slim, but you could theoretically get a build up of water above your ceiling, causing it to sag. This would be more likely on older ceilings that have thinner coats of plaster but far more coats of paint, which is quite flexible. Again, check above the water to see if you can find a source.

Ice Buildup

For those of you in the cooler parts of the world, ice damming is a thing you might be aware of. This is when water runoff—often from snow melting on your roof—freezes around the edge of your property, causing an ice dam behind which water can build up. The problem is roof tiles are designed for water to run down the roof, not up. Standing water on your roof will just seep in under the tiles.

A buildup of ice around the edges of your roof can cause an ice dam, water backing up behind it and seeping through the gaps in your roof tiles.

A buildup of ice around the edges of your roof can cause an ice dam, water backing up behind it and seeping through the gaps in your roof tiles.

Damp on the Walls

If you spot damp patches on the walls—particularly on the upper parts of the walls—it could be a sign that water is leaking in and running down the edges of your property. Again, this could be a leaking pipe, but tracing a potential roof leak back from here is tricky, because the water could have taken a windy path down to where you’ve spotted it.

Verifying It’s a Roof Leak

When it comes to roof leaks, all roads lead upstairs. Your first port of call should be a quick visual inspection of your property from the outside, assuming your roof is visible from the ground. I wouldn’t recommend climbing up there unless this is the kind of thing you do for a living, or you have an easy and safe way to do so. The most obvious thing you are looking for is damaged or missing roof tiles, as this would indicate a clear point of water ingress. If your roof doesn’t have tiles, look for any other obvious signs of damage.

If you can get up into the loft, take a bright torch with you and give the inside of your roof a close inspection—being careful not to step on anything that is not meant to be stepped on. If in doubt, stick to the rafters. Any sign of moisture on the inside of your roof is bad. It could be that you haven’t got a leak as such, but moisture is forming in your loft due to poor ventilation, with the end result being the same.

Final Thoughts

Of course, once you have an idea of where and why the leak is happening, you then have to do something about it . . . and this is where I stop giving advice. If you know how to handle these things, you won’t need my help. And if you don’t know how to handle these things, my advice is to call someone who does.

Plumbing isn’t the kind of thing that you should dive into without a little training, and climbing on your roof isn’t something you should do at the best of times. It helps to know the cause, so you know what steps to take (for example, shut the water off, or call a roofer), but if the remedy is something more involved than shutting off a tap that’s not been closed properly, it’s best left to the professionals.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2021 John Bullock

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