K Rend cleaning across the North East

K Rend is a through-coloured render: the colour runs through the material rather than sitting on top as paint. It looks crisp when new, but within a few years most K Rend walls develop green algae on the shaded sides, red or orange streaks, or black spotting, and the bright finish turns patchy.

K Rend cleaning has to respect the finish. High pressure erodes the surface and leaves clean streaks that never blend back, which is why we soft wash it. A dilute cleaning solution is applied at low pressure, left to work on the growth, and rinsed gently. The wall comes clean evenly, because the solution kills the algae rather than scraping a visible layer off.

K Rend is one of several render systems we clean; the approach on this page applies to monocouche and similar through-coloured renders too. For render generally, see render cleaning, and for the soft washing method itself, see soft washing.

The red or orange streaking common on K Rend is a type of algae, and it is stubborn because it roots into the surface. Green film is algae too, while black spots are usually lichen. All three respond to soft washing, though red staining and lichen can take more than one treatment or a few weeks to fade fully after the visit. Our guide to K Rend white patches covers another common worry: pale marks that appear after cleaning or weathering.

Because the growth is killed rather than blasted off, the finish is not eroded and the wall stays cleaner for longer. Our guide how to clean K Rend walks through the process, and K Rend vs monocouche cleaning explains how the systems differ.

We do not publish fixed K Rend cleaning prices. The cost depends on the area of render, how high it sits, how heavy the staining is, access around the house, and whether more than one treatment pass is likely. Our K Rend cleaning cost guide explains those factors, and the quote form is the quickest route to a figure for your walls.

If you are collecting quotes, ask each K Rend cleaner how they intend to wash the walls. Anyone proposing high pressure on a through-coloured render is proposing to erode it, and the streaking that leaves cannot be blended out afterwards. A low pressure soft wash is the method the finish is designed to tolerate.