Professional Render Cleaning

Why render goes green, red and black in the North West

K-Rend, monocouche and the other through-coloured renders went on thousands of houses across Lancashire and Greater Manchester in the last twenty years, on new estates in Buckshaw Village, Cottam and Whitefield and as a facelift on older semis in Bury, Bolton and Blackburn. They look sharp when they are new. The catch is that the surface is porous, and in a climate this wet it stays damp for weeks at a time. Green algae takes hold on the shaded side of the house first, red algae shows up as streaks under the sills and along the base, and the black staining is a fungus that follows a year or two behind.

None of it is dirt in the ordinary sense, so rain does not wash it off and scrubbing makes it worse. It is a living growth, and unless the growth is killed it comes straight back.

Soft washing is the only method we use on render

Render should never be pressure washed. High pressure takes the top coat off, leaves patches and streak marks that cannot be undone, and forces water into the wall behind. We soft wash instead: a professional biocide applied at low pressure, left to work, then rinsed gently where it needs it. The render is not scoured, the colour comes back evenly, and the treatment keeps working after we leave, so the last of the staining fades over the following weeks.

On painted and smooth render the same method works without touching the paint. On pebbledash and roughcast, common on the 1930s semis in Prestwich, Radcliffe and Great Harwood, soft washing is the only way to get into the texture without knocking the stones out.

Cleaning versus repainting

A lot of people ring us because they have had a quote to repaint. On a house that has simply gone green, cleaning costs a fraction of painting and gives you the original finish back rather than a coat on top of it. If the render is cracked, blown or genuinely faded, we will tell you, because painting over algae without killing it first is money down the drain.

A soft wash lasts two to three years before anything shows again on the shaded elevations, longer on the sunny side. Plenty of our customers in Rossendale and Burnley have us back every third spring and the house has never looked tired since.

What render cleaning costs

The price depends on the wall area, how many storeys, how heavy the staining is and what we need to protect: plants, cars, neighbours' windows. A gable end is a quick job; a whole detached house with a conservatory against it takes most of a day. Send photos of each side and your postcode and you will get a fixed price, usually the same day.

Where we clean render

Render cleaning in Rossendale, Burnley, Blackburn, Bury, Bolton, Preston and Manchester, and everywhere between. We do a lot of commercial render and cladding too, on offices, schools and retail units, with RAMS supplied: see commercial cleaning. If the roof above the render is mossy, have both done together, because moss sliding off the roof is what streaks the render below the gutters in the first place.