Render Respray Sheffield: Recolouring the Whole House

When a whole-house respray is the right job

The render has to be sound first. Coating over hollow or cracked render only hides the problem until it fails, so the house is surveyed and repaired before any colour goes on; see repairing render across the house. If most of an elevation turns out to be hollow, it needs re-rendering rather than respraying.

What the coating is depends on what is on the wall. Painted sand-and-cement render is recoated with a masonry paint compatible with the existing paint. Through-coloured scraped render is different: K Rend's FAQ advises washing its through-coloured renders rather than painting them, because paint loses the render's water repellency and breathability, and its product guide offers Colour Enhance, a coating designed for existing scraped render. Lime render takes limewash, not modern paint, which SPAB warns can trap moisture in an old wall.

A coating also has limits you should know before choosing it. It evens out colour, not texture: a smoothly floated repair in a scraped wall, or a patch with a finer grain than the render around it, still catches low sun differently after one colour has gone over both. If the texture difference matters to you, ask whether those areas should be re-rendered to match before the house is coated.

Cleaning and preparation round the house

Every elevation is cleaned before coating. K Rend's maintenance advice is a pressure washer on a fan nozzle at low power, with mild detergent, working top to bottom, because very high pressure damages render. Green and black growth on shaded or north-facing walls is treated with a biocide and given time to work before washing off.

Then the repairs: cracks filled, small holes made good with a colour-matched filler, rust stains from old brackets dealt with and the brackets replaced with stainless ones. Old flaking paint is scraped back to a firm edge. The coating manufacturer's primer, where one is required, goes on once the wall is clean and dry.

1. 1

   Survey and sound each elevation; repair hollow and cracked areas first.

2. 2

   Treat algae with a biocide, then wash each face at low pressure, top to bottom.

3. 3

   Fill cracks and holes, remove loose paint and replace rusting brackets.

4. 4

   Mask windows, doors, roofline, paths and anything within reach of overspray.

5. 5

   Prime if the coating system requires it, then apply the coats one elevation at a time.

6. 6

   Unmask, refit fittings and check every face in daylight.

Spraying a whole house

Spraying is fast on large, plain elevations, but it puts paint into the air. On a whole house that means masking every window, door, sill, fascia and gutter, covering paths and planting, and watching the wind, because overspray travels to cars and neighbouring houses. On a semi or terrace, a clean line at the party wall is masked so the neighbour's render keeps its colour. Small, fiddly areas such as reveals are often brushed or rolled even on a sprayed job.

Coatings have weather limits like any render product. Check the data sheet for the minimum temperature and drying conditions of the product actually chosen; K Rend's thin-coat data sheet, for instance, sets 5C for the air and the wall and no damp or frozen backgrounds. A coat applied on a cold, damp Sheffield morning will not cure properly.

Choosing one colour for the house

Pick the colour against the whole building: the roof, window frames, any retained stone or brick, and the house next door. Look at a sample on a sunny face and a shaded one, at different times of day.

In a conservation area, check with the planning authority before a dramatic colour change; Sheffield's appraisals explain the character each area is trying to keep. Afterwards, the house is cared for like any render: a gentle wash every few years and a biocide where algae returns.