Help with paint Painting outdoors

How to paint an exterior wall

An exterior wall is painted in two coats of Masonry Paint — a matt, breathable, mould-resistant paint made for render, brick and concrete — after an honest diagnosis, a thorough clean, the repair of cracks and, if the surface chalks, a stabilising primer. You need three to five dry days between 10 and 25 °C, in the shade, out of the wind. What it does not do: hold on a lime render, which needs a mineral paint, or cover wood and metal, which have their own finishes. And before the first stroke of the roller, a prior declaration of works at the mairie.

Page updated September 2026 · by the Mylands France colour team

Rendered house façade freshly painted in a warm matt stone-white, grey-green shutters, exposed stone plinth, clear sky, soft shadow — Lots Road No.24 in Masonry Paint: matt, breathable, on a cement render

Understanding

What a masonry paint is, and what it holds on

A façade takes everything: rain, frost, sun, moss, and the damp that rises from the ground or passes through the wall. A masonry paint therefore has to do two contradictory things: repel the water that comes from outside and let out the vapour that comes from inside — a paint that seals the wall blisters in one winter. Mylands Masonry Paint is a matt, microporous paint, resistant to moss and algae, formulated for cement render, brick, concrete, rendered blockwork and reconstituted stone.

What it does not go on: a lime render or a soft stone, which need a mineral paint (silicate or lime) to breathe; wood and metal, which take the Multi-Surface finishes; a damp wall, whose cause has to be dealt with first. A wall that leaves a white powder on the finger (chalking) still holds, but needs a stabilising primer before the paint; a wall whose render sounds hollow is repaired, not painted.

The mairie first. Repainting a façade, even in the same colour, requires a prior declaration of works (déclaration préalable) in most communes; in a protected area, the Architecte des Bâtiments de France gives an opinion, often against a communal colour chart. Allow a month's processing.

Diagnosis

What the wall is telling you, and what to do before painting

The symptom	What it is	The remedy
White powder on the finger	Chalking: the old paint or the render is breaking down at the surface	Brush, wash, then stabilising primer; paint once dry
Fine network of cracks (crazing)	Shrinkage of the render, no movement	Wash; Masonry Paint covers them in two coats
Crack over 1 mm, or one that follows a corner	Movement of the structure	Open out, fill with sealant or flexible filler; if it is growing, a builder's opinion before anything
Render that sounds hollow	Detached from the substrate	Hack off and re-render; wait a month before painting new render
Green or black marks	Moss, algae, mould — north face, under gutters	Fungicidal wash, leave to work, brush, rinse; check the gutter
Tide marks, salts, paint blistering at the bottom	Rising or penetrating damp	Deal with the cause (drainage, gutter, render); do not paint until the wall is dry
Paint flaking in sheets	Old non-breathable or poorly bonded paint	Scrape off everything that comes away, brush, stabilise, paint

The tape test: stuck onto the old paint then ripped off in one go, it should take nothing with it. If it lifts paint, the paint gets scraped; if it lifts powder, the surface gets stabilised.

Close-up of a rendered wall under preparation: one area brushed and clean, another still green with moss, stiff brush and fungicide sprayer on the ground — Fungicidal wash, brushing, rinsing: a clean surface first — and two days' drying

The method

Painting a façade in eight steps

01

Protect and mask

Dust sheets over plants, the ground, window sills; tape on the joinery, gutters, boxes. A stable ladder or a mobile scaffold tower: you do not paint a façade from a stepladder.
02

Treat the moss

Fungicidal wash sprayed on the green or black areas, left to work as the instructions say (often 24 h), then brushed with a stiff brush and rinsed. On a very dirty wall, a low-pressure washer, never high pressure on an old render.
03

Wash and scrape

Sugar soap with a scrubbing brush over the whole surface, rinsed with clean water. Scraper on everything flaking, wire brush on what chalks. Two days' drying in dry weather.
04

Repair

Cracks opened into a V with the scraper, dusted out, filled with sealant for fine ones and exterior filler for wide ones; chips and losses made good with filler. Drying as the product says, a light sanding.
05

Stabilise if the surface chalks

Stabilising primer by roller on the powdery areas — or over the whole façade if it chalks everywhere. It consolidates the surface and evens out absorption; without it, the paint pulls away with the powder. A night's drying.
06

First coat

Masonry Paint well stirred, long-pile roller on the surfaces, brush in the corners, under the sills and along the joinery. No thinning. Work in whole elevations, from one corner to the other, without stopping in the middle of a wall: the join would show.
07

Second coat

After the interval on the data sheet — the next day is the safe rule outdoors. Same method, crossed: if the first went on vertically, so does the second, always laying off in the same direction.
08

Unmask and keep an eye on it

Tape removed as soon as the second coat is touch-dry. No rain forecast in the next 24 h. Then, every five to seven years: a wash, and a maintenance coat on the most exposed face.

The weather

When to paint a façade

The weather does half the work. You need between 10 and 25 °C, air and wall; no rain forecast for 24 h after each coat; no full sun on the wall while you paint — follow the shade round the house: the east face in the morning, the west face in the afternoon; no wind, which dries the paint before it has flowed out and lands dust on it; no mist or dew. May–June and September are the best months; July–August only early in the morning; never in frost.

The quantity: Masonry Paint covers according to the porosity of the surface — take the coverage on the technical data sheet for a smooth render, and a third more for a roughcast or brick. A rough render is painted with a masonry brush rather than a roller, and drinks more.

The colours

Six façade colours, with their joinery

A façade looks lighter and cooler than on the card: a pure white dazzles, a pure grey turns blue. Six façade shades chosen for outdoors, each with the shutter colour that suits. The method: Using exterior paint colours.

Warm stone-white

The façade white par excellence: warm, calm, it does not turn blue to the north or dazzle to the south.

Façade · Lots Road No.24 Shutters · Long Acre No.102

Cool white

For a townhouse under slate, or a modern house: a white with a hint of grey, with dark joinery.

Façade · St Clement No.11 Joinery · Bond Street No.219

Cream

The cream of country houses and mas: warm, it goes with tile and bottle green.

Façade · Cavendish Cream No.120 Shutters · Sorrel Green No.207

Stone

A limestone beige for a façade that has to agree with stone surrounds or the neighbours.

Façade · Cadogan Stone No.59 Shutters · Messel No.39

Pale ochre

The soft ochre of southern villages: never a yellow, a warm sand that takes the evening sun.

Façade · Walbrook No.142 Shutters · Hurlingham No.181

Warm grey

For a suburban or contemporary house: a grey-beige that stays warm under a grey sky, with white and black.

Façade · Hoxton Grey No.72 Joinery · Downing Street No.10

To avoid

What makes a façade blister

Painting over moss or powder. Paint holds on what is underneath; if what is underneath comes away, so does the paint.
Painting a damp wall. After rain or washing, two days' drying; after new render, a month.
Masonry Paint on a lime render. It needs a mineral paint; otherwise blisters and peeling within a year.
Full sun and wind. Visible joins, dust stuck on; follow the shade.
Stopping in the middle of a wall. The join shows in every raking light; a whole elevation, corner to corner.
A high-pressure washer on an old roughcast. It tears it off and drives water in; low pressure and a brush.
Forgetting the mairie. The prior declaration, a month ahead.

Painter on a mobile scaffold tower rolling a second coat of matt stone-white onto a render with a long-pile roller, the first coat visibly lighter, shutters masked with tape — A whole elevation, corner to corner, in the shade: the second coat the next day

Frequently asked questions

Your questions, our answers

Can a brick façade be painted?

Yes, with Masonry Paint, on sound, clean, dry brick; the pointing is made good first. Be aware it is irreversible: a painted brick never goes back to bare. Soft or old brick deserves a professional's opinion.

How do I know if my render is lime?

A house from before 1950, a soft render that scratches with a fingernail, a white powder, a surface that absorbs a drop of water in a few seconds: probably lime. A drop of acid (vinegar) that fizzes confirms it. In that case, a mineral paint, not Masonry Paint.

How long does a painted façade last?

Ten years and more on a sound, well-prepared surface, with a wash every five to seven years and a maintenance coat on the most exposed face. The north face greens before it wears; the south face chalks before it greens.

Do I need a primer over the whole façade?

Only where the surface chalks or is very absorbent (new render, bare concrete). Over sound old paint, washed and dry, Masonry Paint goes on directly in two coats.

Can a garden wall or a low wall be painted?

Yes, like a façade; the top of a low wall is the weak point, water stands there: a coping (tile, stone, zinc) before the paint, or it flakes from the top down. See How to update outdoor spaces.