Ask three people what "like for like" means and you may hear three answers. To a planning officer it is a repair that leaves the character of a building unchanged. To an owner it is a patch that does not stand out. To a roofer it is a list: the same material, the same size and thickness, the same colour and weathering, the same fixing and the same detail at every junction. All three are describing one idea, which is that the part removed is replaced by something that does the same job in the same way and looks the same afterwards. For a house in Bath, that idea matters more than it does elsewhere. Listed buildings are everywhere, a good part of the city sits in a conservation area, and the roof is often the most visible original part of a house. Matching works differently for each roofing material, there is a line between a repair and a change, and a few clear questions asked of your roofer before any work begins keep the repair safely within consent where consent applies.
What matching actually involves
A like-for-like repair is judged against the roof that is already there, not against what the roof might ideally have been. It begins with looking at the existing roof closely enough to describe it.
Four things are matched. The first is the material itself: slate goes back as natural slate, clay as clay, stone tile as stone tile, and lead as lead. The second is the size and shape of the individual units, since slates and tiles on older roofs are often cut to varied sizes. The third is the appearance, meaning colour, texture and the surface wear that years of weather have left. The fourth is the method, which covers how the units are laid, how they are fixed, and how each junction is dressed.
The method is where many repairs depart from the original without anybody intending it. A roofer who nails a slate with a stainless clip, then seals a flashing with mastic where the original would have had a lead soaker tucked under each course, has changed the way the roof sheds water. The roof may look identical from the street and still behave differently, and if the sealant fails, the repair fails with it.
It also helps to understand what is not matched. The pitch of a roof, its overall form, the height of its ridge and the line of its eaves are fixed by the building, and a repair does not alter them. The same applies to the profile of a chimney stack and the position of every pot. These are what give a Bath terrace its recognisable skyline, which is why a repair that changes them is a different kind of job.
The test we apply is simple. Stand across the street after the work, and ask whether someone who knew the building well would see where it had been touched. If not, and if the roof sheds water as it did when it was built, the repair is likely to be like for like. If the answer is uncertain, the council should be asked.
Slate, clay and stone tiles
Covering materials are the most visible part of the roof, so the match here is the one people see first. Each has its own quirks.
Natural slate
Slate varies by quarry, by grade and by age. Older Bath roofs often show Welsh slate, which weathers to a recognisable blue-grey, and the Bath Preservation Trust's casework on a Grade I building on St James's Square puts natural Welsh slate across the main slopes. A new slate from a different source can differ in colour, in thickness and in the way it weathers, and the difference stays visible for years. For that reason the best match for a few missing slates is often salvaged slate from the same roof or from a reclaimed supplier. Diminishing courses, where slates get smaller towards the ridge, add another factor, because the replacement must be cut and sorted to suit its position in the roof, not simply taken from a pack.
Clay and stone tiles
Clay plain tiles and stone tiles share the problem of colour and profile. Clay tiles are hand-made or machine-made, and the surface texture of one can look different beside the other. Stone tiles are heavier, thicker and uneven, and are usually graded in courses from large at the eaves to small at the ridge. The B&NES conservation area appraisals for villages south of Bath note that Cotswold stone tiles survive on some roofs and should be kept where they do. Replacing them with concrete tiles is described in the Freshford and Sharpstone appraisal as something that detracts markedly from the area.
Substitutes
Man-made slate and concrete tiles are lighter and cheaper, but they are not the same material, and a swap from one to the other is a change of appearance and sometimes of weight. A covering that is heavier than the old one affects the structure and may bring in Building Regulations. On a terraced roof at Lambridge Place the Trust welcomed a return to natural Welsh slate over an artificial product, which shows the direction it favours.
Lead, mortar and the details nobody sees from the street
The covering shows. The details underneath often do not, and they are where a lasting repair is won or lost.
Lead
Lead is the traditional material for flashings, valleys, parapet gutters, hip and ridge rolls, and chimney trays. Three lead parts do most of the work. The flashing closes the gap against a wall or chimney. The valley lining carries water down where two slopes meet. The soakers are little folded lead pieces, one per course, that guide water back onto the slates beside an abutment. Repairing lead like for like means using lead, laid in the traditional way with rolls, drips and laps that allow it to expand and contract. Spreading a bitumen strip or a tube of sealant over a split in the lead is a quick patch, not a match, and it often hides a failure that continues beneath.
Lead is supplied in different thicknesses, graded by code, and the choice is made to suit the job and the exposure. The specification is written into the quote, so you know exactly what goes on your roof.
Mortar and pointing
Chimney stacks and copings in old Bath stonework were built in lime mortar, a softer material that lets the wall breathe. Modern cement is stiffer and denser than the stone around it, so moisture that gets in has to leave through the stone, and the stone is what decays. At 7 Walcot Buildings the Trust asked for lime in the repointing and in new flaunching on a chimney, and observed that cement could have aggravated the decay of the stack. A like-for-like repair to stonework uses lime mortar, in a mix that matches the original joint's colour and grain.
Ridge and verge
On older roofs the ridge tiles sat in a mortar bed. A repair may keep the look of a bedded ridge while adding mechanical fixings, because current practice does not rely on mortar alone. That is a method change that respects the appearance and meets current standards.
Where like for like ends and consent begins
"Like for like" is not a permission in itself. It names a kind of work, and the consent that work needs turns on the building in question.
For a listed building, the council that decides on listed building consent is B&NES, and it stresses that consent and planning permission are two different permissions. Its guidance says owners should make contact ahead of any works, and describes unauthorised work as a criminal offence. In practice, owners and officers often take the view that a small repair using the same material and method is a different thing from a change, but the council, not the roofer, makes that call. Repairs that look minor, such as replacing a run of slates or rebuilding a flaunching, are exactly the kind of work on which to ask first. The council's listed buildings guidance has contact details for its conservation team.
Outside a listing, a house in the conservation area has less formal protection, but the principle is the same. Certain streets carry an Article 4 direction that withdraws some permitted development rights, and the council's policy map shows which ones. The examples the council gives for these directions are porches, windows, doors, painting and sheds. Roofs are not named, so the direction on your street needs to be checked rather than assumed. If you plan to change the covering material or its look, raise it with B&NES planning first.
If you are unsure whether your repair counts as like for like, ask before you order the work. The conversation takes little time, and a written reply is worth keeping. If the council says consent is needed, the repair is delayed, not lost, and a temporary make-safe can keep the weather out while it is arranged. Our guide to temporary roof repairs sets out what those stopgaps involve.
How a matched repair is surveyed, specified and recorded
A repair that has to match is specified more carefully than one that does not, and the process is worth understanding because it gives you something to hold your roofer to.
It starts with the survey. We go up, photograph the damaged area and its surroundings, and note the type, size and condition of the existing covering, the nails and fixings, the state of the battens and the make-up of every junction. Where we can, we lift one or two slates or tiles to see what is underneath. Photographs of your own roof go with the written findings, so the record shows what was there before the work.
The written scope follows. It names the material to be used, the source of any replacement units, whether they are salvaged, reclaimed or new, and the fixings. It describes how each junction will be made, whether in lead, in lime mortar or otherwise. It states what is renewed and what is retained. It gives a fixed price for the work, and it makes clear who deals with building control where that applies.
If the match cannot be made with confidence from stock, a sample is the answer. A reclaimed slate or tile laid loosely beside the existing roof lets you and a conservation officer judge colour and weathering before the work starts. Reclaimed stock is variable, so a sample from the actual batch is more useful than a photograph of the supplier's best.
After the work, the record is completed with photographs of the finished repair, so that the file shows before and after. For anyone who later sells the house, or applies for consent for something bigger, that record shows the roof has been looked after with care. Keep the file with the deeds, along with the name of the slate or tile used, so a future roofer can match it again without guessing.
Common questions about matching, and related problems
Some matching questions come up often enough to deal with together.
The first is whether a leak in an older roof should be sealed with a modern product. Usually not. A sealant on a slate roof, a lead gutter or a stone coping can hold for a short time, but it cannot address the cause, and it can make a later proper repair harder because the surface needs cleaning off first. If a stain has appeared on a ceiling, our short answer on a ceiling water stain explains how to trace the source before choosing any repair.
The second is whether to repair or re-cover. On a historic roof, repair is almost always the preferred route, because it keeps the most original fabric. When a roof is too far gone, a full re-covering in the same material may be the answer, and that is a bigger job with its own consent and Building Regulations questions. We recommend repair where repair works.
The third is whether accessories such as bird proofing, solar panels or aerials change the position. They can, because they add fixings and alter the look of the roof. Our guide to bird proofing on Bath roofs explains how fixings are made on old stone and lead so that the system can be removed without lasting marks.
The last is cost. A matched repair costs more than a quick one, because the materials are harder to source and the methods take longer. The roof repair guide from MyBuilder (2026) reports typical UK ranges that start low for a small fix and climb with the scale of the work, and a heritage match can sit above them. Your fixed price depends on what the survey finds. Your fixed quote follows the survey. For the wider picture of repair work, see our roof repairs service.