Owners of period houses in and around Bath often hold a second building of some age: a coach house at the end of the garden, a stable block turned garage, a wash house, a lean-to store against the boundary wall. The roof on it may be leaking, sagging or covered in a patchwork of repairs, and the owner reasonably wants it done quickly and cheaply. Then comes the question of whether the building is protected, and by what. The answer depends on how the property is designated, where it stands and what the work will change. This guide explains the layers that apply: listing, the conservation area, the World Heritage Site and Article 4 directions. It shows what local casework says about slate, clay and stone coverings, and it sets out how to ask the council the right questions. Treat it as general guidance rather than legal advice, because the decision rests with the council.
Which designation applies to the outbuilding
Three different things can apply to a roof in Bath, and people tend to mix them up.
The first is listing. A listed building is protected nationally by Historic England's list, and consent for changes is decided by the local council. For Bath, the deciding body is B&NES Council. The city contains around 5,000 listed buildings, so a period house with a listing is far from unusual. The question for an outbuilding is whether it is itself on the list, or whether it is treated as part of the listed house through its relationship to it. That is a legal judgement, and the sensible course is to treat it as open until the council has told you. Do not assume that a small, plain outbuilding at the end of the garden is free from the house's listing.
The second is the conservation area. The conservation area for Bath dates from 1968 and covers roughly half the area of the World Heritage Site, so your street may be in it or out of it. A building can be in the conservation area without being listed, and the controls are lighter but still real.
The third is the World Heritage Site. The whole of Bath is inscribed, under a boundary that follows the city boundary. The status shapes planning policy for the city, and it is one of the reasons the council pays attention to appearance, but it is not a separate consent that you apply for.
Outside Bath the same ideas apply, with a different council. Properties in Wiltshire, Somerset, South Gloucestershire or North Somerset deal with their own councils, and Historic England's list is national. Our page on outbuilding roofs covers the practical side of ordinary, unprotected outbuildings.
What the council says about work to a listed building
B&NES gives short, plain advice on its listed buildings page. Its opening advice is to consult the council ahead of any works to a listed property. It separates listed building consent from planning permission, which are different permissions with different tests, so holding one tells you nothing about the other. Unauthorised work carries criminal liability. For an owner, the practical meaning is that guesses cost more than phone calls.
Re-roofing is a good example of why. Swapping a worn covering for one of the same material and pattern can look like a plain repair. On a listed building the council will want to know what is there now and what will go back, because a change of material, coursing or detail alters the character the listing exists to protect. Moving from natural slate to an artificial slate, or from clay to concrete, is a visible change. So is losing a stone verge or a lead roll.
The conservation team takes calls on 01225 394041, Tuesdays and Thursdays, and has the email address conservation_andplanning@bathnes.gov.uk. Planning queries go to development_management@bathnes.gov.uk. You will find the council's wording in its guidance for owners of listed properties.
At a listed outbuilding we photograph the roof, note each material, and write a specification covering the existing covering, the proposed repair and the detail at ridge, eaves and verges. You then have a concrete document to send the council in place of a vague description.
Conservation areas, Article 4 directions and the World Heritage Site
In a conservation area, changes that affect appearance get more scrutiny than the same changes elsewhere. The point is not to stop work. It is to keep the character of the street and the grouping of buildings, and a roof, being so exposed to view, counts for a great deal in that.
Article 4 directions are one mechanism. They withdraw some of the usual freedoms to alter a property without applying, in places the council wants to protect. The council describes them as protecting special places, the Bath World Heritage Site among them, and the subjects it names are porches, sheds, repainting and replacement windows and doors. A roof is not mentioned. Streets differ, so find your address on the policy map held by the council and ask directly whether anything touches the roof. We do not tell clients that re-roofing in Bath needs planning permission, because that is not what the council says. Nor do we tell them it never does.
The World Heritage Site designation sits above all of this. It does not give you a form to fill in, but it helps explain why the council cares about materials and appearance across the city, including on buildings that are not listed. Alongside this, the Bath Preservation Trust responds to applications, and its casework is a useful guide to what the city's heritage bodies look for. You can read about conservation areas on the Bath Preservation Trust conservation area page.
Roof windows and rooflights raise questions of their own in these settings, and the page on conservation rooflights deals with them.
What Bath casework suggests about materials
No published B&NES guide sets out rules for re-roofing listed buildings, so the best evidence is casework, where the Bath Preservation Trust has commented on specific proposals. These are examples, not policy, but they show how the city's heritage bodies think.
At 33 St James's Square, a Grade I building, the Trust's comments record the main slopes in Welsh natural slate with clay pantiles on the rear pitch. The Trust backed fresh lead lining for the valley gutters, and it supported taking off asbestos slates. At Lambridge Place, a terrace with a mansard and built-in dormers, it backed natural Welsh slate as the replacement for artificial slate. At 7 Walcot Buildings it urged lime mortar for the repointing and the flaunching, observing that cement could have aggravated the stone decay in the stack.
The lesson across these cases is matching. Natural slate stays slate. Clay stays clay. Lime is preferred to cement. A mansard has a steep lower slope under a shallower upper one, and it is far more visible from the street than a pitch tucked behind a parapet. A flaunching is the mortar fillet that seals the base of a chimney pot, and where it is cement, it can trap damp in old stonework.
Outside Bath the pattern holds. B&NES conservation area appraisals for Wellow and Freshford describe clay tiles as common, with original Cotswold stone tiles surviving in places. Wellow's appraisal calls the surviving stone tiles rare and says to preserve them. Freshford's says concrete tiles laid over a stone roof detract markedly from it. A coach house roof may therefore be a stone or clay roof worth keeping, not just a covering to be replaced.
That is the approach we take: the roof as built, put right. Sound stone tiles and slates stay, replacements match what they replace, and the unseen parts get proper attention.
Repairing a historic roof: what to look for first
Coach house and stable roofs have their own habits. They are often long, simple pitches with few interruptions, and they may be older than the house roof, carried on heavy timbers.
Fixings and nail sickness
Slate roofs fail at the fixings long before the slate itself gives out. Iron or poorly galvanised nails rust, and the slate slips. Conservation advice favours copper, aluminium or silicon bronze for a lasting fix. If an old outbuilding roof is shedding slates, the covering may be fine and the nails finished, in which case the roof can be stripped, the good slates set aside, and the roof built up again on fresh battens with durable fixings.
Timbers and ventilation
Old roofs breathe. Gaps at eaves and between boards let air through, and that moves moisture out. Tight modern insulation or a sealed membrane can interrupt it, so any change to what lies under the covering needs thought. Our page on garage roof condensation explains how moisture builds up when air movement is cut off.
Rainwater goods and drainage
A coach house beside a boundary wall may have a valley, or a lead gutter behind a stone parapet, shared with the neighbouring property. These are hidden, and they are where many leaks begin. Our guide on garage roof leaks covers how water gets in at such details.
Bats and nesting birds
Old outbuildings are favoured by both. Bats, their roosts and nesting birds are protected, so if you find signs of either, stop and take advice before disturbing the roof.
If the outbuilding is being converted or reused
A change of use is a different order of question from a repair. Turning a coach house into a studio, a home office or an annexe brings in Building Regulations for insulation and weatherproofing, and in a listed or conservation setting it brings in consent too. The roof is often the biggest single decision, because a better-insulated roof is a thicker one, and thickness changes the look from outside.
Our page on the roof of a converted garage has the detail. For a protected building, the right order of events is simple: speak to the council about the principle, agree what the roof will look like, then specify the build-up to fit within that. Reversing the order tends to mean drawings that cannot be built.
For repairs with no change of use, the same discipline applies in a lighter form. Write down what is there. Photograph it. Describe what will go back. Share it before work starts, not after.
Costs follow the detail. Typical UK ranges from MyBuilder's slate roof cost guide (2026) show how far apart natural slate can be depending on origin, with Welsh at £140 to £180 per square metre installed and Spanish at £100 to £130. Period detailing takes longer than a modern roof and is priced accordingly, with a fixed figure agreed after the survey.
How we approach a protected outbuilding
For a listed or conservation-area outbuilding, we start by surveying the roof and photographing each part, so a record exists before anything changes. We work out what the covering is, judge how much of it can be kept, and then examine the lead, the ridge and the timbers underneath.
We then explain consent in simple language. We tell you what we think needs asking, and who to ask at B&NES or at your own council if you are outside it. Where Building Regulations apply, we handle that side. We do not make the planning decision, because it belongs to the council, and we do not suggest that work can proceed before it has spoken.
Where a repair will do, a repair is what we recommend. Where a covering has to be replaced, we match the material to what was there. Once we have surveyed the building, the price is fixed in a written quote, and our workmanship guarantee lasts ten years, set down in writing.
If your outbuilding is a garage in everyday use, rather than a historic coach house, the regulatory position may be simpler. The page on when garage roofs need approval deals with that case, and the garage roofing hub lists the other work we take on.