Limewash Paint on Exterior Brick and Stone

Short answer. Limewash and lime based paints work well on porous outside surfaces such as soft brick, old stone and lime render, because they soak in and let walls breathe. They do not bond well to hard, glazed bricks or to walls already coated in modern masonry paint. Outside work needs dry, mild weather, and the finish needs renewing from time to time.

Which outside walls suit limewash

Limewash has been used on British buildings for centuries, especially on rubble stone, cob and lime render. It suits surfaces that are porous, meaning they soak up water. Good candidates include the following.

• soft, handmade or older bricks;
• limestone and sandstone;
• lime render and roughcast;
• walls that already have old limewash.

Hard, dense bricks, glazed bricks and cement render are less absorbent, so limewash may not grip well. Walls with modern masonry paint usually need that paint removed first, as lime will not bond to it.

If you are not sure how absorbent a wall is, flick a little clean water at it. If it darkens and soaks in quickly, it is porous. If the water beads and runs off, limewash is unlikely to grip well without more work. Look at the pointing too, as loose or crumbling mortar should be repaired, ideally with a lime mortar, before any finish goes on.

Why breathability matters outside

Older solid walls take in rain and dry out again through both faces. A breathable finish such as limewash lets that moisture escape. A plastic based masonry paint can trap water in the wall, which may lead to flaking, damp inside and frost damage to soft bricks and stone.

Zavoré's Lime Paint is a natural lime based breathable paint made for interior and exterior walls, and it suits lime plaster, brick and masonry.

Weather and timing

Lime needs time to cure, and the weather affects it. In general, avoid the following.

• frost, or nights that may drop near freezing in the days after;
• rain on the fresh coat;
• hot, dry weather or strong wind, which dry it too fast and can make it powdery.

Mild, still, overcast spells are ideal. Damp the wall with a fine spray before each coat so it does not suck the water out of the limewash. Protect fresh work with hessian or sheeting if rain or strong drying is likely.

Upkeep and colour

Outside limewash weathers slowly. It is common to refresh it every few years, sooner on walls that face the worst weather. Because it is thin and soaks in, a new coat goes straight over the old one with little preparation beyond brushing off loose material.

Colour comes from lime stable pigments, mostly earth colours such as ochres and oxides. These give soft, chalky shades. Our guide to choosing limewash colours explains how colours change as they dry.

Listed buildings and conservation areas

If the building is listed, changing the outside finish or colour can need listed building consent, and so can internal work. In a conservation area there may be other controls. Ask the local council's conservation officer before booking any work.

For a colour test before you start, order a sample board, call 07592 929191 or email sales@zavore.co.uk. Our limewash installation page explains how our own team works.

Questions we get asked

Can I limewash over masonry paint?

Not usually. Lime does not bond well to modern masonry paint, so it normally has to be removed first.

How often does outside limewash need redoing?

It is common to refresh it every few years, depending on how exposed the wall is.

Will limewash stop damp in a brick wall?

No finish cures damp on its own. Limewash lets a wall dry out, but the cause of damp, such as leaks or high ground levels, needs fixing.