Rendering in Spetisbury, one half of a pair

Tapping first. A hammer handle down the wall tells you more than any photograph. Sound render rings hard, blown render sounds hollow. On a semi the blown area frequently carries on past the party line, because both halves were rendered on the same day by the same gang.

Hacking off and rebuilding. Where it has parted from the background it comes off, back to sound brick. Loose joints behind it are repaired, the background is primed if it is dusty, then a mesh reinforced basecoat and the finish. We cut a clean vertical stop at the party line rather than feathering the new work into the old.

Silicone thin coat. Through coloured, applied thin over a reinforced basecoat, flexible and easy to wash down. It is the usual choice on the post-war cavity walled stock in the village, and on a shared elevation it has the advantage that the colour can be matched close to whatever is next door.

Monocouche. One thick through coloured coat, ruled and scraped back to an even texture. Good on a plain gable, and no painting afterwards. It needs a stable background and a planned stopping point, which on a terrace means the corner or a bead on the party line.

Sand and cement, pebbledash and Tyrolean. Traditional scratch and float coats, and dash where the elevation already carries it. On a matching pair the aggregate match matters more than anywhere else, so we put a sample panel up and let you look at it in daylight before committing.

Older solid walls. One home in five here predates 1919. A solid wall has no cavity and was built breathable, taking moisture in and letting it dry back out. A plastic rich modern system leaves that moisture trapped and pushes it through to the inside face. On period fabric we render in lime, which stays open and moves with the wall.

Beads, bellcast and stop ends. A bellcast throws water clear at the base, a stop bead gives a clean edge at a reveal or against a neighbour, and an angle bead keeps a corner true. A movement joint goes in where the elevation is long or where two structures meet, because that is where a crack will otherwise choose to appear.

Cracks, delamination and green staining. A hairline crack running straight across a panel is shrinkage. A crack that steps through the render and into the brickwork behind is movement, and covering it up wastes your money. Algae on a shaded wall is a wash and a treatment; a topcoat that chalks off is a recoat.

External wall insulation. Board fixed outside and rendered over, on a render carrier where the background will not take a direct fix. On a semi it changes the wall thickness on one side only, so the junction at the party line and the eaves needs designing rather than improvising.

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 terraced front with the pavement right against it, a semi with a side gate and a drive, and a detached house with a conservatory on the back elevation are three different access jobs. 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.

On a semi or in a terrace the elevation was built as one wall and finished as one wall, and it still reads as one wall from the road. So the first decision is not the colour, it is the stop. A clean vertical bead on the party line gives a deliberate edge that looks like a design choice. Feathering the new render out into the old gives a wavy join that catches the light and looks like a repair for the next thirty years.

The second decision is your neighbour. You do not need their permission to render your own wall, but you do need access to work on it, and where the job means cutting into or fixing to a party wall there are formal notices under the party wall procedure. The pairs that end up looking best are the ones done at the same time on a shared scaffold, and we will quote both halves and split it.

We cover the village, Charlton Marshall, Sturminster Marshall and the lanes along the valley, broadly DT11, 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.