Render colour and masonry paint on the UK shelf, and which choices you cannot undo

On a British house the wall colour arrives by one of two routes. Either it is in the render itself, mixed through a silicone or acrylic topcoat and left as it comes off the trowel, or it is in masonry paint applied over render that is already on the wall. On the day the scaffold comes down the two look the same. Five years later they do not, because one of them can be changed with a brush and the other cannot.

That is the question this page answers, and it needs numbers rather than opinion: if the render is coloured through, can the same colour be reached later in paint at all?

The two shelves are not the shape you would expect

On the UK market the render shelf is the deep one. It holds 10,196 active positions in 25 lines from 4 manufacturers, Baumit, Ceresit, K Rend and Sika, which is the largest render shelf on any market in this cluster. Masonry paint is the short shelf: 2,801 positions from 6 manufacturers, Armstead, Crown, Cuprinol, Dulux Trade UK, Farrow & Ball and Jotun.

Stripped of duplicates, the render positions collapse to 1,780 distinguishable colours and the paint positions to 2,558. The paint shelf has more distinct colours in total and still cannot cover the render shelf, because the two are spread across different parts of colour space: fandecks are built around what people paint walls, render charts around what people specify on new build and refurbishment.

The number that decides the question

Of the 1,780 distinguishable render colours:

• 842 have a paint twin at two suppliers or more,
• 458 have one at exactly one supplier,
• 480 have none at all.

So slightly more than a quarter of the render shelf cannot be reproduced in masonry paint by any of the six decks on the market. Those 480 are not scattered evenly either. They fall as red (125), brown (82), green (77), beige (75), blue (75), grey (40), purple (6), and the pattern behind that list is saturation: the misses are the chromatic mid-tones, the dusty reds and olive browns that a render chart carries because a mineral topcoat can hold them, and a wall-paint deck largely does not. Baumit PuraTop 1311 (#6B5151), a muted brick red, has nothing within reach on the paint shelf; the nearest chip is a different colour, not a near miss. Same for PuraTop 0931 (#5F5A4E), an olive-grey, and for GranoporTop 1162 (#E0D459), a strong soft yellow.

The 458 with exactly one supplier deserve their own warning, and the supplier list explains it: Jotun 274, Dulux Trade UK 135, Farrow & Ball 16, Armstead 14, Crown 11, Cuprinol 8. Overall coverage runs Jotun 1,058, Dulux Trade UK 877, Crown 376, Farrow & Ball 340, Armstead 185, Cuprinol 120. Where the twin exists once only, the repaint has already chosen its brand, and if that brand is not what the decorator buys locally in a trade tub, the practical answer five years from now is closer to none than to one.

What this means before the scaffold goes up

Colouring through the render is the better job in almost every respect: no repaint cycle, no film to fail, colour that goes right through the topcoat rather than sitting on it. The catch is not quality, it is reversibility.

If the render colour has twins at two or more suppliers, nothing here should worry you. Whatever you choose, the wall can be repainted in the same colour later, from more than one counter, and colour is not part of the risk.

If it has exactly one, write the brand and the code down and keep them with the house papers. That single chip is the whole future of the colour.

If it has none, understand what is being decided. The wall can of course be painted later, in a colour that exists. It just cannot be painted in that colour. For a deliberate, unusual render tone, that is a fair trade and worth making with open eyes. For a colour picked because it looked good on a sample board, it is an expensive way to find out.

There is a version of this decision that keeps both options open: put the unusual colour on the part of the elevation that is small and cheap to redo, and keep the main volume on a render colour that the paint shelf can hold.

K Rend Silicone K1 matched to masonry paint

The standard K Rend chart is the one most British specifications name, so it is a useful place to see the three cases side by side.

Read the bottom two rows of that table against the top four. The whites, creams and greys of a standard render chart are covered several times over, because that is where a masonry paint deck is deepest as well. Terracotta and Salmon Pink are already at the edge: nothing on the paint shelf lands on them, only near them. Push one step further into the chromatic part of the Baumit or Ceresit charts and the near misses stop as well, which is how 480 colours end up with nothing.

How these matches were calculated, and where they stop

Every pairing comes from a colour-difference calculation (CIEDE2000) over the measured values both catalogues publish, not from holding two boards up to a window. Three rules apply.

Words, not scores. Each pairing is described in plain language. A colour can hold its lightness perfectly while its hue drifts, and the drift is what the eye catches on a wall, so where that happens the wording says so.

Only colours somebody measured. Where a manufacturer publishes no colour value, there is nothing to compare, and the position is left out rather than guessed at.

A value is not a surface. Through-coloured render at 1.5 mm grain and masonry paint on a smooth substrate never read identically, even at an identical value, because texture changes how light leaves the wall. A scraped or roughcast finish widens the gap again. These matches tell you whether the colour exists on the other shelf. They do not promise that the finished walls will be indistinguishable.

Before

After

Related guides

• How to choose an exterior paint color: the method for choosing the colour itself, once the reversibility question is settled.
• Siding colors matched to paint: the same comparison for panel and paint on the American shelf.
• Siding and paint colours that match on the Canadian shelf: the same question with a different pair of shelves.
• Why your siding color looks different from the sample: why colour on the wall never matches the sample in your hand.

Frequently asked questions