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Outside designated areas the test is appearance. The Planning Portal states that cladding may be carried out without having to first apply for planning permission provided the materials are of a similar appearance to those used in the construction of the house, which is why re-rendering a rendered house is usually uncontroversial and rendering a brick house is not.

Inside designated areas the test disappears and permission is simply required. The same guidance is that if you live in a Conservation Area, a National Park, an Area of Outstanding Natural Beauty or the Broads, you will need to apply for planning permission before cladding the outside of your house with stone, artificial stone, pebble dash, render, timber, plastic or tiles. National planning practice guidance adds that permitted development rights are more restricted in conservation areas generally, and that planning permission is required for the demolition of certain unlisted buildings in conservation areas.

Listed buildings are stricter again. The guidance is that any works to demolish part of a listed building, or to alter or extend it in a way that affects its character as a building of special architectural or historic interest, require listed building consent, that undertaking such works without consent is a criminal offence, and that even minor works have the potential to cause substantial harm depending on the nature of their impact on the asset and its setting. Cement-rendering a historic brick or stone elevation is exactly the kind of proposal that needs asking about first.

The combustible materials ban is tied to building height and use, not to cladding in general. The Building (Amendment) Regulations 2018, in force from 21 December 2018, require that materials which become part of an external wall, or a specified attachment, of a relevant building are of European Classification A2-s1, d0 or A1. A relevant building is one with a storey at least 18 metres above ground level containing dwellings, institutions, or rooms for residential purposes, with hostels, hotels and boarding houses excluded, and a list of components is exempted, including cavity trays, window frames and glass, door frames, membranes, seals, gaskets, fixings, thermal break materials and fire-stopping materials.

That means an ordinary two-storey house is not within the ban, but it does not mean fire is irrelevant to a wall finish. Approved Document B remains the fire safety guidance in England, published in Volume 1 for dwellings and Volume 2 for buildings other than dwellings, and the government published frequently asked questions following the ban on combustible materials in external walls.

Flats are a different world. GOV.UK's criteria state that a higher-risk building under the Building Safety Act 2022 is a building in England that is at least 18 metres in height or has at least 7 storeys and contains at least 2 residential units, with the height measured from ground level to the top of the floor surface of the top storey, and such buildings are directly overseen by the Building Safety Regulator. The Act itself is structured in parts covering the regulator and its functions, the Building Act 1984, higher-risk buildings, and other provision about safety and standards, which includes the remediation of certain defects. If you own a flat rather than a house, cladding work is a building-wide question and not a personal renovation.

It starts with the wall, not the finish. A competent contractor wants to know what the wall is built of, whether it is solid or cavity, why the existing finish failed, and whether the elevation is wet from a defect elsewhere such as a failed gutter or a bridged damp-proof course. Rendering over an undiagnosed damp problem seals it in and produces a worse one two winters later, which is the single most common way these jobs go wrong.

Preparation then does most of the work. Old, blown or loose material is hacked off, the substrate is repaired and keyed, beads are set at corners, reveals and stop ends, and the ground clearance below the damp-proof course is respected so the new finish does not bridge it. Timber, board and tile-hung finishes need battens creating a ventilated, drained cavity, with the cavity closed against vermin at top and bottom but left able to breathe and drain.

Detailing at the edges is where a system succeeds or fails: window and door reveals, the junction with the roof and eaves, the head of the wall, the sills, and every penetration for pipes, vents and fixings. Curing matters too, especially with cement and lime renders, which need protection from direct sun, frost and driving rain while they gain strength, so a British programme is weather-dependent and a contractor who will not delay for a forecast is not doing you a favour.

Not all cracks mean the same thing. Fine crazing across a surface is generally a shrinkage or finish issue, while a crack that steps through the render along a diagonal, or opens and closes with the seasons, is telling you about the wall or the ground underneath rather than the coating. Tapping a suspect area gives the other answer: a hollow sound means the render has lost its bond and is blown, and blown render does not reattach itself.

Trapped moisture is the characteristically British failure. A hard cement render applied over a soft, solid, historically breathable wall stops the wall drying outwards, so moisture that gets in behind, through a crack, a failed gutter or at the head of the wall, stays in. The result is damp inside and render that eventually pushes off in sheets. Approved Document C is the England guidance on resistance to moisture in floors, walls and roofs, including examples of damp proofing and ventilation provisions, and any specification worth accepting should be able to explain how the wall will still dry.

The cosmetic complaints usually have the same root. Green or black algae on a north or shaded elevation, staining below a sill without a proper drip, and dirty streaks beneath a gutter joint are all water going where the detailing let it, not the finish being defective in itself.

Get the system written down, not just the price. That means the make-up of the wall as found, what is being removed, the base coat and finish or the board, the fixings and battens, the insulation and its thickness where insulation is involved, the beads and the detailing at reveals and at the base of the wall, and how the wall is intended to dry. Where the work crosses the thermal element threshold, the specification is also your evidence that the insulation met the standard the Approved Documents require, with Approved Document L the England guidance on the energy performance of new and existing buildings.

Then check who stands behind it. Ask whether the guarantee is insurance-backed so it survives the contractor, and what it excludes. TrustMark describes itself as the government-endorsed quality scheme covering work a consumer chooses to have carried out in or around their home, and registered businesses commit to its standards and its complaints route. Note as well that HSE's CDM guidance makes a domestic client any individual having construction work done on their home, or a family member's home, outside a business, with the client duties passing to the contractor on a single contractor project or to the principal contractor where more than one contractor is involved.