There is no birthday on which a roof must be replaced. A well-laid tile roof can outlast the people who bought the house, and a badly laid one can need attention in its first decade. What matters is the condition of the covering, the underlay beneath it and the timbers that carry both, and the pattern of faults they show. A single slipped tile is a repair. A roof that sheds a handful of tiles each winter, leaks in more than one place and has damp patches across the loft rafters is telling you something different. This guide lists the signs we look for, the order we weigh them in, and the way the decision comes out for different materials.
Not every fault means the roof is finished, so for earlier warning signs that repair can still fix, see signs of roof damage.
This guide covers the end-of-life signs only, and does not weigh up cost; for the decision itself, read our guide to roof repair or replacement.
Start with the pattern, not the single fault
One broken tile, one leaking flashing or one cracked ridge is a point failure. Point failures are normal and cheap to fix, and nothing about them says the roof as a whole is finished. What counts is whether the faults are isolated or spread, and whether they keep coming back. Two repairs in ten years on separate slopes is routine maintenance. A new leak every autumn, in a different place each time, suggests the underlying layers have reached the end of their useful life.
Age matters mostly as a clue to what has happened. A roof from the 1930s may still be sound if it was built with good clay tiles and a lapped underlay of bitumen felt. A roof from the 1970s with early interlocking concrete tiles and untreated softwood battens might be tired much sooner. A roof laid in the 2000s on cheaper breathable membrane can show premature wear where it was left exposed to sunlight at the eaves. We never recommend replacement on age alone, and our guide on how long a new roof lasts explains why.
Signs on the outside
From the ground, with binoculars if necessary, you can spot several things:
- Slipped, cracked or missing tiles in several places. This shows that the nails or clips are failing, not that someone has been unlucky.
- A sagging ridge line or a dipping slope. It points to tired timbers or a spreading roof structure.
- Heavy moss or lichen. A little is cosmetic. A thick mat holds water against the tile, and on old concrete tiles the surface layer breaks down, leaving rough, crumbling faces.
- Tile surface wear. Concrete tiles lose their coloured top coat and go pale or sandy. Clay tiles can spall, where the face flakes off in layers after frost.
- Crumbling mortar at the ridge or verge. This is repairable alone, but a whole ridge of failed bedding on an old roof usually points to age everywhere else.
- Lifting or rusted flashings. They fail earlier than the tiles and can be replaced separately.
None of these is a verdict by itself. Together they build a picture, and our page on re-roofing versus roof replacement explains what the choice is between.
Signs from inside the loft
The loft tells the truth that the outside hides. On a dry day, take a torch up and study the inside face of the slopes. You are looking for four things. Daylight coming through between tiles is a clear sign of gaps, though a few pinpricks along the eaves may be deliberate ventilation. Dark stains on the rafters, battens and underside of the underlay mean water has been getting in. Damp, soft or crumbly timber around the wall plate and the foot of rafters suggests a long-term leak. And a torn, sagging or perished underlay, which on older roofs can be brittle as paper, shows the secondary line of defence has failed.
Underlay is the key piece. Modern tiles are designed to let a certain amount of wind-driven rain past, and the underlay does the real waterproofing. If the underlay beneath a tile roof is rotten, re-fixing tiles on top of it will not help, because the tiles must come off to renew it anyway. At that point the cost of the labour is the same as stripping the whole slope, and a replacement of the covering becomes the economical choice. Our short guide on what stripping a roof involves shows the work involved.
Signs from the rooms below
Brown rings on a ceiling, peeling paint above a window, musty smells in a bedroom and mould on the upstairs corners are the symptoms most homeowners notice first. They do not always mean a roof failure. Condensation, a leaking pipe or a blocked gutter can cause the same marks. Tracing the source is part of the survey, and our page on tracing a leak to its source describes the method step by step. What counts as evidence for replacement is a leak that keeps returning after proper repairs, or several leaks at once in separate parts of the roof.
How the decision differs by material
Concrete tiles. The tile body usually outlasts its surface. Once the face wears away and the tiles absorb water, they get heavier and can crack on frosty mornings. If the underlay is sound, tiles can sometimes be cleaned and kept. If both are tired, replacement is right.
Clay tiles. Good clay is long-lasting. The usual failure is at the nibs, the small lugs that hook over the battens, or with the nails. A roof like this may need re-battening and re-fixing and not new tiles, and old tiles can often be sorted and reused. See can old roof tiles be reused for how that works.
Natural slate. Slates generally outlast their fixings. Iron nails rust through and slates slip, so a slate roof may need re-slating with the original slates after the nails are replaced with copper or stainless steel. If the slates themselves are laminating, flaking in layers, they are finished. Our slate section covers the signs a slate roof needs replacing.
Flat roofs. Felt, EPDM and GRP are judged by their surface and the deck under them. Blistering, splits at the upstands, ponding water and a soft or spongy feel underfoot all point to the deck or insulation below having been wet. Once water is trapped, patching the surface treats the symptom only.
What a survey adds
A homeowner can see a lot, but not everything. A surveyor can walk or reach the roof, check the fixings, lift tiles to test the underlay and measure moisture in the timber. Photographs of every finding go into the report, so you see the evidence rather than take our word for it. Sometimes the answer is reassuring. A roof that looks shabby may have years left, and a repair or a clean costs a fraction of replacement. Sometimes the news is less welcome, and then we show you the photographs of the underlay, the timbers or the fixings that decided it.
Two roofs, two decisions
Picture two semis on the same Basingstoke estate, both built in the same decade. The first has a ridge that has been re-bedded twice, a handful of tiles replaced after storms, and a loft where the underlay is sound and the rafters are dry. That roof has years left, and the sensible plan is a service every few years, not a strip. The second has a similar outside but a loft with brown tide marks down the underlay, a corner of the wall plate that gives under a screwdriver, and daylight where the felt has split at a valley. From the road the two roofs look much alike, yet one wants maintenance and the other wants renewing. This is why we keep saying that the outside of a roof is only half the evidence, and why a survey beats a drive-by quote.
Next, consider the work already planned for the house. Loft conversions, solar panels, new roof windows or an extension that touches the roof slope all put a scaffold on the house and open up part of the covering. If the existing roof is near the end of its life, fitting those on top of it can mean paying twice. Planning the replacement first, or at the same time, usually costs less than reopening the same slope a few years later. Our guide on re-roofing with in-roof solar shows how that sequencing works in one case.
The cost side
Replacement is a major spend, so it helps to see it against repeated repairs. Cost guides report typical UK figures of £6,500 to £10,500 for a full re-roof of a three-bed semi in concrete tile, and £4,000 to £13,000 for a new roof on a semi-detached or detached house. Your fixed quote follows the survey, which sets the price against your roof. A useful test is to add up what you have spent on repairs in recent years and what the next round is likely to cost. If you are patching annually and each patch is a stopgap, replacement is not a luxury but the cheaper route over time. Our page on how much a new roof costs goes deeper.
Waiting too long
Homeowners sometimes delay because a roof still looks fine from the garden. Damage that begins under the covering can go unseen for several winters, which is how a small slipped tile becomes a rotted wall plate.
Delay has a price. Water that enters slowly rots timber, soaks insulation and can reach ceilings, wiring and plaster before anything shows on the surface. Replacement of a few rafters or battens is part of a normal re-roof, but replacement of the ceilings and the structure under them is a different scale of bill. If your roof is showing multiple signs, getting it surveyed sooner usually costs less than waiting for the first big leak, and the work can be planned for dry weather instead of done in an emergency.
When the time comes, a survey from us is free and includes photographs of your own roof. Our line is 01256 213956, and a WhatsApp message with a couple of photos also gets a time booked. Our page on roof replacement in Basingstoke sets out the whole service.
