There is no age at which a roof automatically needs replacing. There are roofs of eighty years that need nothing and roofs of twenty-five that are finished. The decision is not about age, it is about whether the components that hold the covering on still have working life in them, and about cost per year, not cost per job.
The four questions worth asking
Rather than a rule of thumb, apply these to your own roof. A roofer who has been in the loft can answer all four.
- Is the covering itself sound, or are tiles and slates breaking up?
- Are the fixings failing across the slope, or is this an isolated fault?
- What condition are the battens and underlay in at the eaves and mid-slope?
- Are the details, ridge, verge, valleys, flashings, sound or all near the end together?
Cost per year is the number that matters
A repair that buys you two years and a re-roof that buys you fifty are not comparable as single figures. Divide each by the years you can reasonably expect from it and the picture usually clarifies quickly. Repeated small repairs feel affordable one at a time and are frequently the more expensive route over a decade, particularly once access costs are counted each time.
When repair is clearly right
A single failed flashing, storm damage to one area, a slipped tile, a cracked valley on an otherwise sound roof, repair, without hesitation. Replacing a serviceable roof because a detail has failed is waste, and any roofer suggesting it should be asked to justify the recommendation in terms of what they found, not what they assume.
When replacement is the honest answer
Slates slipping steadily across a slope from nail fatigue, battens that crumble when touched, underlay perished to the point that it tears on contact, several details failing at once, or a covering that is delaminating, at that point patching is buying weeks. We will say so, put both prices on paper, and let you decide without pressure.
Common questions
How long should a roof last?
It varies enormously by covering, exposure and how it was built. Rather than working from an average, we would rather look at your battens, fixings and details, which tell you what is actually left.
Will you tell me if I do not need a new roof?
Yes. A large share of the work we do is repairs on roofs that other people have suggested replacing.
Can a roof be replaced one slope at a time?
Sometimes, where slopes are independent and access allows. It costs more overall because access is paid twice, but it can spread the cost when that matters.
Does replacing a roof add value to the property?
It removes a known liability from a survey, which matters at sale. We would not claim a specific figure, that depends on the property and the market.