Rendering in Winterborne Kingston, wet ground

Tapping the elevation. A hammer handle over the wall separates render that is still bonded from render that has blown. Around here the hollow band runs along the base, sometimes the full width of a house, and it is always wider than the crack that made you ring.

The base detail. Render should stop on a bellcast bead above the damp proof course with a visible gap under it, so water is thrown clear instead of running back behind. Where a previous job has taken the render straight down into a path or a border, it has bridged the damp course, and correcting that is the first thing on the list rather than an optional extra.

Hacking off and rebuilding. Blown render comes off back to sound masonry. Loose joints are repointed, the background cleaned down and stabilised where it is dusty, then a mesh reinforced basecoat and the finish in coats. A damp wall needs time between coats and we build that into the programme.

Lime on period solid walls. The pre-1919 cottages have solid walls with no cavity, built breathable so moisture soaks in and dries back out through the face. On wet ground that drying route matters more, not less. Lime keeps it open, moves with the wall and can be patched. A plastic rich modern system traps the moisture and pushes it inside.

Silicone thin coat and monocouche. Good systems on a modern cavity wall, and most of the village is exactly that. A stabilising primer where needed, a mesh reinforced basecoat, then a through coloured topcoat that sheds water and needs no painting. Both still want the base detail right, because no topcoat fixes a bridged damp course.

Sand and cement, pebbledash and Tyrolean. Scratch coat, float coat and dash where the elevation already carries it. Patches are matched to a sample panel where the aggregate is still obtainable, and where it is not we say the repair will read differently.

Beads and movement joints. Bellcast at the base, stop beads at reveals and eaves, angle beads on corners, and a movement joint where an elevation is long or two structures meet. A joint put in deliberately saves a crack appearing where it chooses.

External wall insulation. Board fixed outside and rendered over, on a render carrier where the background will not take a direct fix. On wet ground the base track and the ground clearance matter more than usual, because insulation sitting in a damp border stays damp.

Cracking, algae and staining. Straight hairline cracks are shrinkage, stepped cracks are movement. Green low down on a wall is a symptom of the damp band rather than a cleaning problem, and treating it without fixing the base books a repeat visit.

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 on soft ground needs the scaffold footings spread properly, a semi with a side passage wants a narrow platform, and a detached house with a conservatory on the back needs the glass protecting and working over. 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.

A winterbourne is a chalk stream that runs only when the water table has risen far enough to reach the surface. It fills through the autumn, runs all winter and disappears in the summer. The stream is only the visible part: under the village the water table does the same, so from November to May the ground beside your walls holds water even in a dry week, and the flood risk service shows how much of the village is on that ground.

For render, that turns two ordinary details into the important ones. First, the ground level. Every border, path or bed that has crept up the wall over the years shortens the gap above the damp proof course, and once the ground is above it the barrier is bypassed. Second, where the render stops. A bellcast bead with clear air under it lets the wall shed water; render taken down to the soil gives it a hard route straight into the masonry. Get those two right and an ordinary system will last here. Get them wrong and it does not matter what you spend on the topcoat.

We cover the village, Winterborne Whitechurch, Bere Regis 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.