Roofers, estate agents and websites use the words re-roofing and roof replacement as if they were the same thing, and in casual conversation they often are. When you ask for quotes, though, the difference can decide the price, the disruption and whether the work needs building control approval. In the usual UK sense, re-roofing means stripping the covering, that is the tiles or slates, and putting a new one on the existing roof structure. Roof replacement is the wider term: it can mean the same thing, or it can mean taking the roof back further, to include repairing or renewing rafters, purlins and wall plates. Between those sit repair at one end and overlay at the other. This page sets out each option plainly and shows how to work out which one your roof needs.
The ladder of options
It helps to think of a ladder with four rungs, from least to most work.
Repair. Fix the specific faults: replace slipped or cracked tiles, renew a flashing, re-bed and mechanically fix a ridge, clear a valley. The rest of the covering stays. This suits a roof that is generally sound with isolated problems.
Overlay. Lay a new covering over the existing one without removing it. In the UK this is unusual on pitched tiled roofs, because the old covering adds weight and hides what lies beneath, but it is used on some flat roofs and on certain sheet roofs. Overlaying a flat roof may be possible where the existing deck and insulation are dry and sound. It is not generally treated as equivalent to a replacement, and it can affect the building regulations position.
Re-roofing (re-covering). Strip the old tiles or slates, felt and battens down to the rafters, check and repair the timbers, then fit new underlay, new battens and a new covering with new flashings, ridge and verge fixings. The structure stays. This is what most people mean when they talk about a new roof.
Full replacement. Everything above, plus renewal of structural timbers where they are failing, which can range from a few rafters and a section of wall plate to a rebuild of the roof frame. It is the most extensive and least common, and it is needed where rot, movement or past alterations have damaged the structure.
When repair is the right answer
A repair is sensible when the covering is sound as a whole and the faults are local. A handful of slipped tiles after a gale, a flashing that has lifted at one chimney, mortar crumbling at a verge, a split in a valley liner: each is a bounded problem with a bounded fix. The test is the condition of the rest of the roof. If the tiles are firm, the felt beneath is intact and the battens hold their nails, then replacing the whole covering to cure a local fault would be wasteful. A repair may last for many more years, and the cost is a small proportion of a re-roof.
A repair is not sensible when problems keep coming back across the roof. Tiles that crumble at the touch, felt that tears when a tile is lifted, battens that have rotted and a pattern of leaks in different places are signs that the whole covering is exhausted. Patching it costs money each time and delays the real fix. The signs are listed under when to replace a roof, and our free survey gives you photographs and an honest view on which side of the line your roof falls. We repair wherever repair works.
What re-roofing involves
A re-roof on a typical house follows a sequence. Scaffolding goes up around the roof. The old covering is stripped in sections, so that the house is not left open to the weather, and the waste is taken away. The felt and battens come off, and the rafters and wall plates are exposed and checked. Any rotten or damaged timber is repaired or replaced. A new breathable underlay is laid, new treated battens are fixed to the correct gauge for the new covering, and the tiles or slates go on, with new lead around chimneys and abutments and mechanically fixed ridge, hip and verge components. Fascias, soffits and gutters may be renewed at the same time since the scaffold is up. Our pages on what stripping a roof involves and the roof replacement process follow the job stage by stage.
A common question is whether the old tiles can go back. Sometimes they can, if they are sound, but old tiles are often brittle and a proportion break when lifted. How that is judged is explained in can old roof tiles be reused.
When replacement goes beyond a re-roof
Once the covering is off, the structure shows what it has been hiding. Most roofs need some timber repair, a rafter foot here and a batten run there, and that is part of a normal re-roof. A more serious replacement is called for when rot has spread through wall plates and rafter feet, when long-term leaks have decayed purlins, when the roof has spread or sagged, or when past alterations such as cut trusses have weakened it. Another cause is a change of purpose, such as converting the loft or adding a heavier covering, which requires the structure to be upgraded. Our guide to structural checks for a heavier roof covering deals with the load side.
The extent of structural work is often unknown until the strip, which is why a good quote explains how timber will be charged. A survey in the loft with a torch and a probe gives a fair idea of what to expect, but it cannot see behind every board.
The regulations: where each option falls
The Planning Portal gives the test for England. Where the work stays under 25% of the envelope and under 50% of the roof, no application is generally expected. Bigger jobs do, and then the insulation of the whole roof may have to be improved under Approved Document L. A covering that is 15% or more heavier than the old one also needs approval, with possible strengthening, under Approved Document A. You can read the details on the Planning Portal.
| Option | What is done | Building regulations position |
|---|---|---|
| Repair | Local fixes, covering stays | Normally no application |
| Overlay | New covering over the old, mostly flat or sheet roofs | Ask building control; may differ from a strip |
| Re-roof, small share of roof | Strip and re-cover part of the roof | Below the thresholds, usually no application |
| Re-roof, large share of roof | Strip and re-cover most or all of it | Approval needed; insulation upgrade likely |
| Full replacement with structure | Re-roof plus rafters, plates or purlins | Approval needed; structure inspected |
The insulation guide at insulation when re-roofing shows what that means in practice, and we handle the application where the work is notifiable. Our answer on replacing half a roof explains why splitting a job does not always avoid the thresholds.
What each option costs
Repair costs a fraction of a re-roof, and the range depends on the fault. For re-roofing, published UK guides put a concrete-tile job on a three-bed semi between £6,500 and £10,500, and standard semis and detached houses between £4,000 and £13,000, for orientation only. Structural work adds to the total and is charged according to what is found. For the full build-up of a price, see new roof costs in detail.
The right comparison is not the price of one job against another but the cost per year of service. A repair that buys five more years of life is good value if the roof is otherwise sound. A repair that buys one winter is poor value. A re-roof lasts many years and settles the question, and it can be time to do it if you are about to spend on a loft conversion, solar panels or an extension that ties into the roof.
A short checklist before you commit
- Do you have photographs of the faults on your own roof, with locations?
- Has someone checked the loft for stains, daylight, wet insulation and rot?
- Is the damage local or spread across several slopes?
- How old is the covering, and what is the underlay like where it can be seen?
- Are there plans for a loft conversion, solar panels or an extension?
- Does the quote say how rotten timber, if found, will be priced?
- Who handles building control notification, and what certificate will you receive?
If most of those have clear answers, you are ready to compare options. If several are blank, a survey is the next step, not a decision. Our guide to how to compare roof replacement quotes helps with the stage after that.
Where the old advice goes wrong
Much of what circulates online about this subject comes from US sources and does not fit British houses. Advice that talks about stripping one layer of asphalt shingles, reusing nails or tearing out walls and ceilings has no bearing on a UK roof with tiles or slates on battens. Claims that a new roof pays back a given percentage of its cost on resale are rarely backed by evidence, and we do not make them. What a sound roof does is remove a worry for a buyer, protect the structure and make survey results easier. Be wary of anyone who sells the idea of a return, and ask for the evidence.
How to decide
Start with evidence. Get a survey with photographs of the covering, the junctions and the loft. Ask what is wrong, how widespread it is and how much life the roof has left. If the faults are local and the covering sound, repair. If the faults are spread and the covering is worn out, re-roof. If the strip reveals structural decay, plan for that too and make sure the quote says how it will be priced. In between, consider the near future: planned extensions, solar or a loft conversion may tip a borderline roof towards renewal. And think about timing, as a planned job is cheaper and calmer than an emergency.
That is how we approach it: we go up, photograph your own roof and tell you where it sits on the ladder. When a roof still has useful service in it, the answer is a repair, and you receive the pictures either way. If it needs more, the fixed written quote names each element. Our roof replacement in Basingstoke service starts with that survey; 01256 213956 is the line to book it.
