How To Tell When A Roof Needs Replacing

How To Tell When A Roof Needs Replacing
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The next time you step outside your house, take a second to look up and inspect the condition of your roof because we are about to reveal how to tell when a roof needs replacing.

The good news is it doesn’t require a long pair of ladders and a head for heights. Many problems with roofs can actually be identified from the ground.

Only if you spot cause for concern will you need to ask a specialist to go up and take a closer look.

So, with that in mind, here is our brief guide on how to tell when a roof needs replacing:


The ridge is the very top of the roof where the two (or more) sides meet. It usually runs the full width of the roof. If this looks particularly uneven, twisted, or curves upwards or downwards, it could indicate that it’s time to call in the roofers.

An uneven ridge may just need the tiles re-laying if it’s particularly old. However, a bowing or sagging ridge could indicate some structural problems that will need the advice of a structural engineer.

A healthy ridge should be straight and level the whole way across.


A few missing roof tiles shouldn’t be too concerning, they’ll need replacing but shouldn’t mean the whole roof needs replacing.

However, if a significant number of tiles are cracked, chipped, or missing, it may be more cost-effective to replace the entire roof rather than repairing the tiles one by one.

Excessive Moss

Moss Causing Roof Issues

If your roof has a significant amount of moss growing on it, it could be causing issues to your roof structure.

The moss has a tendency to grow between the gaps of tiles, gradually forcing them apart and creating openings where water and other debris can penetrate.

Falling Mortar

When checking your roof, don’t just look up! The ground can have clues too. If you are finding bits of mortar around the edges of the building or in the guttering, the chances are they came from your roof.

They may signify that some repointing is necessary but could also be the first signs of a roof needing to be replaced.

Damp Patches

damp patch on ceiling of room
This damp patch on the ceiling of an upstairs bedroom was caused by a hole in the lead flashing of the chimney.

Heading back inside, if you notice damp patches on the ceiling or upper walls of rooms on the top floor of your property, that could indicate a leaking roof.

Try to trace the cause of the damp back to its origin; you may need to enter the loft space (if possible) to do this.

A damp patch on the ceiling of an upstairs room doesn’t necessarily mean that you need your whole roof replaced though. We spotted such a damp area in one of our bedrooms.

After some investigation in the loft, which smelled of rain, we called in a roofer. He found that we had a hole in the lead flashing of our chimney. Once this was repaired, the damp patch dried out, and we haven’t had a problem since.

Deteriorating Underlay

Pitched roofs are usually built with a fabric underlay beneath the tiles. If you head up into your loft space you should be able to identify the underlay pretty easily.

Check that the underlay appears in good condition and is not deteriorating in any areas.

While you’re in the loft space during the day, turn off the lights. If you see any daylight coming in through the roof then it indicates there are gaps or holes in your roof that will need attention.

Damage To Flat Roofs

Flat Roof Repair

Flat roofs are commonly used for extensions and other add-ons that weren’t part of the original fabric of the building. Because of the nature of flat roofs, water will tend to sit on them for a little while after a period of rain.

This is not usually too much of a concern, but, if the water is taking more than two days to disappear, it could be a sign your flat roof needs replacing.

Other things that indicate a flat roof is ready to be replaced include cracking of the roof or loose roof felt.

How To Tell When A Roof Needs Replacing – Summary

As you’ve read, there are a number of things you can do to check the condition of your roof without having to even touch a pair of ladders.

Knowing when a roof needs replacing is a good skill to have as it means you’re more likely to spot issues early, and that can save you considerable money when it comes to paying for repairs.

Just ensure that if you do spot a potential problem that you call in a suitably qualified expert to have a look.

If you need some work carried out to maintain or replace your roof, you may also find our article on how to hire a skip useful.


  • Paul James

    Paul James, is a marketing expert with a passion for property. As well as being a property investor, Paul has also worked within the marketing departments of some of the UK’s leading estate agents. Paul is the founder of Property Road.

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