Looking after linseed oil paint

One of the best things about linseed oil paint is how little it asks for once it is on. Instead of cracking and peeling, it ages slowly and predictably, and a little care every few years keeps it working for decades. Here is what to expect and what to do.

The first few weeks

Linseed oil paint is dry enough to recoat in about 24 hours in good conditions, but it keeps hardening for weeks. During that time:

• Avoid washing or scrubbing the surface.
• Be gentle with doors, windows and anything that rubs.
• Indoors, keep rooms aired and let in daylight — the paint cures best with oxygen and light.

Freshly painted linseed surfaces are slightly elastic and pick up dirt more easily at first. After a few years the surface becomes more “self-cleaning” as the outermost pigment wears.

How linseed oil paint ages outdoors

How fast depends on which way the surface faces and how exposed it is. Typically:

1. Loss of sheen. The surface goes from a soft sheen to matte.
2. Chalking. A fine powder of pigment appears on the surface. Rub it with a finger and colour comes off. Some of this may wash down onto surfaces below in heavy rain.
3. Thinning. Eventually the paint wears thin on the most exposed areas, such as sills and the bottom rails of windows.

None of these stages involve peeling. That is the point: the next step is maintenance, not a strip-back.

Cleaning

Wash painted surfaces with Allbäck linseed soap mixed with water until it foams. Use a sponge or soft brush, rinse thoroughly and let it dry. For mildew, use Linseed Soap Extra and let it soak in before scrubbing lightly. Avoid strong, high-pH cleaners — they can make linseed oil paint yellow — and avoid high-pressure washers.

Reviving a matte or chalky surface

When the surface looks dry, matte and chalky:

1. Wash it with linseed soap, rinse and let it dry.
2. Warm a little boiled linseed oil and wipe or brush it on thinly.
3. Wipe off whatever has not soaked in after 15–20 minutes.

The surface regains its sheen and its protection. Linseed oil wax can be used in the same way for a silkier finish — one thin coat only. Where the paint has worn thin, add one fresh coat of the same colour instead.

Touching up

Damaged spots can be touched up with the original colour at any time, without sanding back the whole surface. New paint will look a little glossier at first, then blend in as it ages. Keep a small amount of each colour you use — sealed tins keep indefinitely.

Preventing mould

In humid parts of Australia, mould is the most common maintenance issue. For exterior work, 10–20% zinc oxide mixed into the paint makes it more resistant. If mould appears on an existing surface, clean it with linseed soap and apply one more coat of the original paint with zinc oxide added.

Indoors: let the light in

Light colours used indoors can take on a slight yellow tone in rooms or cupboards with little daylight, or behind furniture and pictures. It usually fades once the surface is exposed to daylight again. Adding a little grey to light colours for dark spaces reduces it. Interior surfaces keep their sheen for many years and need far less maintenance than exterior ones.

A safety note

Rags used with linseed oil, wax or paint can self-ignite. Put them in a bucket of water before disposal.

Common questions

How often does linseed oil paint need maintenance?

It varies with exposure. Sheltered walls may need nothing for many years; sills and west-facing walls need attention sooner. Allbäck rates the paint at 20–25 years before recoating on a well-prepared surface.

Can I paint acrylic over it later?

It is not recommended — you lose the benefits of the system. Maintain it with oil or linseed oil paint instead.

Questions about your surface?

Get in touch. See also painting weatherboards and painting timber windows.