The short answer
A repair is the right choice when the damage is limited and the rest of the roof is sound. Examples are a few slipped tiles, a failed section of flashing or a leak with a clear cause. A new roof makes sense when the covering is worn out across the whole slope, when problems keep returning, or when the timbers underneath are affected. Repairs cost far less on the day, but repeated repairs to a failing roof can add up to more than replacing it. The real prices homeowners paid are shown elsewhere on this page, so use them alongside this guide.
How they differ
Roof repair deals with a specific fault. Typical jobs include:
- replacing cracked, slipped or missing tiles or slates
- re-bedding ridge tiles or hip tiles
- renewing flashing around chimneys, dormers and roof windows
- patching or replacing a section of felt or membrane
- clearing and fixing valleys, gutters and fascia connections
- making storm damage safe and weatherproof
The rest of the roof stays as it is. The work is usually quick, often finished in a day, and may be done from a ladder or a small access tower.
A new roof means stripping the existing covering from the whole pitched roof and replacing it. That normally includes new battens and underlay, and often new flashings, ridge and verge details. Damaged rafters or other timbers are repaired or replaced as part of the job. It is a bigger project that needs scaffolding, careful planning for the weather, and several days or longer depending on the size and complexity of the roof.
There is also a middle route. Sometimes one slope, or one section such as a rear extension roof, is renewed while the rest is left alone. This can suit a roof where wear is uneven.
Cost: what makes each more or less expensive
A repair is almost always cheaper than a new roof in total. Per job, though, the cost varies a lot.
What pushes repair costs up:
- Difficult access, such as a steep or high roof, which may call for scaffolding even for a small job.
- Hard-to-match materials, such as old clay tiles, natural slate or handmade tiles.
- Hidden damage. A leak may have soaked insulation or timbers, so the visible fault is only part of the work.
- Emergency call-outs after storms, when demand is high.
- Awkward areas like chimneys, valleys and roof windows, where the work is fiddly.
What pushes repair costs down: easy access, common materials, a single clear fault and flexibility on timing.
What pushes new roof costs up:
- Larger or more complicated roofs, with many hips, valleys, dormers or chimneys.
- The choice of covering. Natural slate and clay generally cost more than concrete tiles, and other materials sit at different points.
- Scaffolding, which is a significant part of any full re-roof.
- Timber repairs once the old covering comes off.
- Extra work that is sensible to do at the same time, such as new fascias, soffits, guttering or insulation upgrades.
- Removal and disposal of old materials.
What can bring new roof costs down: a simple roof shape, a like-for-like covering, sound timbers and a quiet time of year for tradespeople.
One point matters here. A repair has the lower price, but a new roof gives you a fresh covering and usually a guarantee. If you are repairing the same roof again and again, compare the running total with the cost of replacing it.
Lifespan and upkeep
A repair does not extend the life of the whole roof. It fixes the fault and restores weather protection, and the remaining covering keeps ageing at its own pace. A well-done repair on an otherwise healthy roof can last for many years. On a tired roof, new faults tend to appear nearby.
A new roof resets the clock. How long it lasts depends mainly on the material, the quality of the fitting and the ventilation and detailing. Slate and clay tend to outlast concrete tiles, and good flashing and underlay matter as much as the visible covering. Ask what guarantee is offered and who stands behind it, whether the installer or the manufacturer.
Upkeep is similar for both:
- Look at the roof from the ground a couple of times a year, and after severe weather. Binoculars help.
- Keep gutters and valleys clear.
- Deal with moss build-up and slipped tiles before water gets in.
- Check the loft after heavy rain for damp patches, daylight showing through, or stained timbers.
- Avoid walking on the roof. Tiles and slates break easily, and falls from roofs are a serious risk.
When to choose Roof repair
Repair is usually the better choice when:
- the damage is local, such as a few tiles, a section of ridge or one failed flashing
- the roof is generally in good condition, with the tiles or slates firm and the timbers dry and sound
- the leak has a clear and fixable cause
- storm damage is limited and you need to make the roof safe and watertight quickly
- you are selling or managing a short-term budget and the roof has no widespread faults
- the roof is fairly young and a fault is down to one poor detail
Repair is also the sensible first step when you are unsure. A competent roofer can often make it watertight and give you an honest view of the condition of the rest.
When to choose New roof
A new roof is usually the better choice when:
- tiles or slates are crumbling, flaking, porous or slipping across large areas
- you have had repeated repairs, and new leaks keep appearing
- the underlay has perished or the battens are rotten
- roof timbers are damaged by damp or rot
- the roof structure is sagging or distorted
- you plan to convert the loft, extend or add insulation, and the work would disturb much of the covering anyway
- the cost of ongoing repairs is approaching the cost of doing the job properly
Bear in mind that a full re-roof may be affected by building regulations, for example around structure and insulation, and listed buildings or conservation areas can have extra rules. Ask your contractor what applies to your property and who handles any approvals. If bats are found in a roof, the law protects them and work may need to be adjusted, so mention any sightings early.
Questions to ask a tradesperson
- What exactly is wrong, and can you show me with photos or from the loft?
- Is this a one-off fault, or a sign the whole roof is failing?
- If you were repairing this, how long would you expect the repair to last?
- What would a full replacement involve, and what would you recommend if it were your own house?
- Does the quote cover scaffolding, waste removal, and making good?
- What happens if you find rotten timbers once work begins, and how will extra work be priced?
- Which materials will you use, and will they match the existing roof?
- Do you have public liability insurance, and can I see proof?
- What guarantee do you give, in writing, and what does it cover?
- How will you protect the house if the weather turns during the job?
- Can I have an itemised quote, and are the start date and the expected duration confirmed?
Get more than one quote, and make sure each one covers the same work so you can compare them fairly.