Roof replacement in Bath, stripped and re-covered properly

Stripping is the first stage and the one that tells us most. Until the covering is lifted, a roof is a surface. Once it is off, the timbers, the nails, the old repairs and the true condition of the underlay are all on view. A good strip is slow and sorted rather than fast and destructive, and it begins with scaffolding.

Scaffold goes up first, along the eaves and often up the gable ends as well, with a working platform and a toe board so that nothing slides off the edge. It also gives a covered route for waste. The MyBuilder cost guide puts scaffolding at about £1,125 as a typical addition to a new roof, which is a real part of the budget and worth finding in any quote.

Working in stages

We open a roof in sections that can be made weathertight again before the end of the working day. The first covering to come off is the ridge, then the courses below it, working down the slope. Slates and tiles are stacked by condition as they come off: sound ones set aside for reuse where the roof is going back in the original material, broken ones into a skip.

Sorting matters on older Bath roofs. A Welsh slate or a clay plain tile that has weathered for generations may be better than anything new that could replace it, and it is also the best match for the neighbouring roof. Reused material is checked piece by piece for cracks, soft edges and split nail holes. What cannot go back is replaced with something matched to it in size, colour and thickness.

What the old roof tells us

The stripped roof reads like a record. Rust stains around the nail points suggest the fixings have failed across the whole slope. Damp, dark rafters under a failed valley point to long-running water entry. A patch of newer timber shows where someone has dealt with a leak before. We photograph these as they appear, because they decide the timber repairs in the next stage and they let us show you the evidence and not ask for trust on the strength of a description.

Waste and neighbours

Stripping makes noise, dust and a great deal of waste. Chutes or enclosed skips keep debris off your garden and the pavement, and a Bath terrace with a shared party wall needs particular care at the junctions. MyBuilder gives waste disposal as anywhere between £100 and £1,000 depending on the size of the roof and the amount of material, so it is a line to check, not assume. Any lead that comes off is taken away for recycling and not left on site.

Chimney stacks, dormers and roof lights are protected or temporarily supported while the covering around them is stripped. The tidy edge at those points is where the new roof will either keep out the rain or leak, so we treat the opening-up as the start of the detailing and not a separate demolition job.

Our guide to scaffolding for a re-roof explains why it is priced as it is, and the page on strip and recover takes you through the same stage in more detail. If you plan to stay at home while this happens, read living at home during a re-roof first. Noise, dust and the loss of access to the loft are the three things households notice most, and each can be planned around.

Slates and tiles shed most of the rain, but they are not waterproof in the way a flat roof is. Wind can drive rain beneath them, and snow can blow in as fine powder. The membrane catches what gets through and carries it to the gutter. It is the sheet fixed over the rafters and beneath the battens. It is easy to overlook because it is hidden, and it is one of the few parts of a roof that can only be renewed during a replacement.

Underlay is the common name for that sheet. Older roofs in Bath often had none, with only a coat of lime hair mortar called torching pressed in from the loft side, or a layer of bitumen felt that has since gone brittle. Modern work usually uses a breathable underlay, one that passes water vapour out of the loft yet blocks liquid water, which helps reduce condensation on the timbers. It is draped slightly between rafters so that water has somewhere to run to and not pool against the battens.

Sarking boards and felt

Some roofs, particularly older slate roofs, have sarking: boards fixed across the rafters with felt laid over them. Sarking gives a continuous deck, and where it is sound it can stay, with new felt and battens over the top. Where the boards are rotten, they are replaced board by board. Sarking changes how the roof breathes, so the membrane and the ventilation have to be chosen together. A breathable underlay laid on boards is not always the right answer, and the loft airflow needs checking before we decide.

The eaves detail

The most common failure at membrane level is at the eaves. If the underlay stops short of the gutter, water can run behind the fascia and into the wall plate and rafter feet. An eaves support tray or a carefully dressed strip of underlay delivers that water into the gutter. We check where the membrane finishes at every eave before the battens go on, because a good layer that stops a few centimetres short of the gutter fails silently.

Laps matter too. Each course of underlay overlaps the one below it, and the laps at hips, valleys and the ridge are sealed or arranged so that water runs over them and not into them. At chimneys and roof windows the underlay is dressed up the sides, so any water that finds its way in is steered away from the opening. These details take time, and they are where a hurried job is easiest to spot.

The membrane is also the layer that holds a roof together in poor weather during the build. Once the underlay and battens are on, a half-finished roof is far better protected than a bare frame.

Many owners ask whether a new covering can simply go over the old one, and the page on roof overlays deals with it. The effect of the work on your insulation is covered in an energy-efficient re-roof, which is useful reading before you choose a membrane. A good membrane is cheap beside the labour of laying it, so it is not a place to economise.

The covering is the part you see, and the one that draws the most opinion. It also carries the largest set of rules. In Bath, where the entire city carries World Heritage Site status and about half of it falls inside the city-wide conservation area, the choice of material is not only a matter of taste. A listed building needs consent from B&NES Council, which is a different thing from planning permission. If your house is listed, or you are unsure, talk to the council before any work is carried out.

Our starting point is to match what is there. Natural slate stays slate, in Welsh or well-chosen Spanish where the original calls for it, and clay or stone tiles stay clay or stone. Where the roof has been re-covered in something poorer in the past, the new roof is a chance to put it right, though that is your decision and the council's, not ours. Our slate roofing page goes deeper on slate, and pitched roofing covers clay, concrete and the roof as a whole.

When a roof needs Building Regulations approval

The Planning Portal says re-covering normally escapes building control approval while it affects well under half of the roof and a modest part of the whole building's outer shell. Beyond either limit, approval applies. The envelope is the whole outer shell of the building, which is why a small house with a large roof can pass the threshold more easily than a large house with a small roof.

Two further points apply however small the job. First, a new covering that weighs 15 per cent or more above the old one needs approval, and the structure beneath is checked against Approved Document A. Swapping lightweight slate for heavy concrete tile is the classic case. Second, where approval is needed, the roof's thermal element, the layer that does the insulating, may have to be upgraded. Approved Document L sets a target of 0.15 W/m²K for a roof element in an existing dwelling, and a replacement element should be no worse than the one it replaces.

Building control comes from B&NES or from a registered building control approver. We explain which route applies, and if the job is notifiable we make the application and see the sign-off through. For the Planning Portal's own wording, see its guidance on re-roofing.

Choosing between covering types

Weight, pitch, appearance and cost all feed the choice. Concrete tiles are lighter on the budget but heavy on the structure. Natural slate is dearer and lasts longer. Clay plain tiles suit many older Bath-area houses and village roofs, and reclaimed material often matches best. A change of material also changes the details at every edge, so the verge, eaves and valley all need working out again.

Figures taken from Planning Portal re-roofing guidance, 2026

The full picture is set out in our guide to Building Regulations for a re-roof, and the page on replacing the roof of a listed building covers consent. The short answer on planning for a re-roof is also worth reading if you are unsure which rules apply to your street. Conservation area status, listing and any local direction all sit alongside Building Regulations and are decided by the council.