Rendering in Cranborne, inside the conservation area

Tapping the wall. A hammer handle run over the elevation separates render that is still bonded from render that has blown and parted from the background. The hollow patch is nearly always bigger than the crack, and on an old wall it follows the line of a previous cement repair.

Taking cement off period fabric. The commonest problem here is a solid wall wrapped in a hard cement render at some point in the last sixty years. The wall was built to take moisture in and dry back out through its face. The cement stops that, so the moisture is trapped and finds the softest route, usually the inside plaster or the brick just above ground.

Lime render. Put on in coats, hair reinforced where the background needs it: a coarse scratch coat left with a key, then a finer float and a finish over it. It is softer than the masonry on purpose, so it takes the movement and the weathering rather than the wall doing it, and it stays breathable.

Like for like repair. Hack off the failed area, square the edges, prepare and clean down the background, then rebuild in matching coats to the same texture. On a conservation area frontage this is usually both the right answer and the quickest route.

Sand and cement, pebbledash and Tyrolean. On the twentieth century houses away from the older core these are ordinary work. Scratch coat, float coat and dash where it matches, patched to a sample panel where the aggregate is still obtainable and replaced wholesale where it is not.

Silicone thin coat and monocouche. Good on a modern cavity wall, wrong on a solid one. Where we fit them here it is on a post-war house or an extension: a stabilising primer on a dusty background, a mesh reinforced basecoat, then a through coloured topcoat. Colour and texture still get checked against the conservation area position first.

Beads, bellcast and stop ends. A bellcast bead throws water clear at the base, stop beads finish an edge at a reveal, angle beads keep a corner straight. On older fabric we often hand form the arris instead, because a machine straight corner on a wall that never had one looks wrong.

Cracking, delamination and staining. Straight hairline cracking is shrinkage. A crack that steps down through the joints is movement, and rendering over it hides it for a season. Algae on a shaded elevation lifts with a soft clean down and a treatment rather than a pressure washer, which on lime does real damage.

External wall insulation. A solid wall has no cavity to fill, so insulation board fixed outside and rendered over is the only way to lift the thermal performance without losing a room. It is rarely right on a protected frontage, since it thickens the wall and changes every reveal, but on a rear elevation it works, with the render on a render carrier where the background will not hold a direct fix.

No rate per square metre, because the square metres are the easy part; what is already on the wall decides the price.

Getting to it. A cottage tight against the street wants a platform that does not block the footway, a farmhouse with open ground round it takes a straightforward scaffold, and a barn conversion with a tall gable needs one that reaches the apex safely. A bungalow gable comes off a tower, a three storey elevation wants a scaffold, and the platform has to stand for the whole system rather than a day. The work at height rules are why it is a priced line rather than something folded into a rate.

What is already on the wall. Rendering over sound brick is one job. Hacking off blown sand and cement, or a pebbledash that has parted from the background, is another, and it is the part nobody can see from the road. We tap the whole elevation before quoting, because the hollow areas set the hours.

The system, and what the wall behind it needs. Silicone thin coat over insulation, monocouche through-coloured, or traditional sand and cement all price differently and behave differently. On a solid wall that has to breathe, a plastic-rich modern system traps moisture and moves the problem inside, so the right system is a wall decision rather than a colour decision.

Comparing quotes? Ask which system is being quoted and how many coats, whether the old render is being hacked off or overlaid, whether beads, bellcast and stop ends are included, whether the scaffold is in the price, and what happens to the existing sills and pipework. Two quotes for the same job are usually two different jobs.

Conservation area status does not freeze a building. It controls how it looks, and for render that means the material, the texture and the colour, because those are what a passer by sees. A wall repaired in the same finish, texture and colour changes nothing anyone can see and counts as maintenance. A wall taken from a soft brush finished lime to a hard scraped through coloured render has changed appearance even at a similar colour, because the texture reads differently in low sun.

The practical route is short. Decide the finish before the scaffold is booked. Get a sample panel on the wall and look at it morning and evening. If the proposal is a change rather than a repair, ask the conservation officer first, because a wall that has to come off again is the most expensive render job there is. And on a listed building do not let anyone start on the basis that render is only a surface. It is listed fabric, and consent covers taking it off as much as putting it back.

We cover the village, Alderholt, Wimborne St Giles and the lanes across the chase, broadly BH21, under Dorset Council. You are dealing with Bournemouth Roofing & Building, the trading name of Bournemouth Roofing & Building Ltd, registered in England and Wales, company number 15471719, which you can look up in a minute. Thomas Hannen's business, and he is the one who comes out to price the job, not a salesman. A verified customer's 10 out of 10 on Checkatrade. The visit and the written quote are both free.