Cedar Siding: Staining and Maintenance in the Northwest

Drive through Camas, Felida, Lake Oswego or the West Hills and you will see cedar on most of the houses: lap siding, shingles, board and batten, trim, decks and fences. It is the right material for the place. It is also the material that needs a maintenance cycle, and most of the tired-looking houses in those neighbourhoods are cedar that missed one.

What the weather does to bare cedar

Unfinished cedar weathers in two stages. First the sun breaks down the surface fibres and the wood turns silver-grey. Then the rain gets into those loose fibres and mildew moves in, which is the green and black you see on the shaded walls. Neither stage is rot, and both can be reversed, but every year it is left the cleaning gets harder and the wood underneath gets a little rougher. Cedar also bleeds tannins, the brown streaks that run from the ends of boards and from around nails, which stain anything light below them.

Stain, not paint, most of the time

Paint sits on top of cedar as a film. On vertical siding under good eaves it can last well, but where water gets behind it, it peels, and cedar's tannins can bleed through light paint unless it is primed with a stain-blocking primer. Stain soaks into the wood instead. It shows the grain, it wears away gradually rather than flaking, and the next coat goes on without stripping. For most cedar siding in this region, stain is the better long-term choice. Houses that are already painted usually stay painted, because getting back to bare cedar is a big job.

Semi-transparent stain

Shows the grain and the colour of the wood with a tint. It needs recoating more often, because the pigment that protects the wood from UV is lighter, but it is the look most people want from cedar.

Solid stain

Looks closer to paint, hides more of the grain, and lasts longer between coats because it carries more pigment. A good choice for older cedar that has been patched or is not uniform any more.

The maintenance cycle

1. Wash every year. A gentle wash in late spring takes off the winter's film before summer sets it. No pressure washer on high: it furs the surface and drives water into the wood.
2. Treat the mildew. On the north and east walls, a mildew treatment rather than just water, or it is back in a month.
3. Recoat before it looks bad. Semi-transparent stain on siding typically wants a fresh coat every few years, solid stain longer. When the water stops beading and the colour looks dull, it is time. Waiting until it is grey means cleaning and brightening before you can stain.
4. Clean and brighten if it has gone grey. A wood cleaner lifts the dead fibres and mildew, a brightener restores the colour and opens the grain, and then it has to dry fully before stain goes on. The same process we use on decks.
5. Stain in the dry window. Roughly May through September, onto dry wood, out of direct midday sun so it penetrates instead of drying on the surface.

New cedar has its own rule

Freshly milled cedar often has a glaze on the surface from the planer that stops stain from soaking in evenly. New siding should weather for a few weeks or be lightly sanded or cleaned before its first coat, and it should get that first coat soon, not next year. Bare cedar left through a Northwest winter is already halfway to grey.

Stains and clear coats from Tall Pine Painting cover cedar siding, shingles, decks and fences across Vancouver, Camas and the Portland metro. Call or text (360) 785-6225 to have yours looked at.

Choosing a stain colour for cedar in this light

The Northwest sky is grey for half the year, and colours that look warm on a sample card in a store read cooler and darker on a wall under it. Cedar tones, honey, chestnut and the natural reds suit the material and the surroundings and are forgiving of the next recoat. Solid stains in deep greens, charcoal and warm greys are popular on newer homes in Camas and Felida and hide patched or mismatched boards well. Whatever the colour, test it on the actual siding, on the shaded side and the sunny side, and look at it on a cloudy day as well as a bright one. The sample board in the sun on a Saturday afternoon is the least representative light the house will ever see.

Shingles, lap siding and board and batten

Cedar shingles have more surface and more edges than any other siding, and they hold water in the overlaps, so they take longer to dry and longer to stain. Semi-transparent stain suits them best because solid stain tends to bridge the gaps and peel. Lap siding is the easiest to keep: the overlaps shed water and the boards are flat. Board and batten has a lot of vertical joints where water runs and where the battens trap it behind them, so caulking the tops of the battens and sealing the end grain matters more than the choice of stain. Trim, fascia and corner boards on all three take the most weather and usually need a coat before the field does.

Tannin bleed, and the brown streaks under the nails

Cedar is full of tannins, which is part of why it resists rot and all of why it leaves brown streaks on light surfaces below it. Rain pulls the tannins out of the end grain and from around nails and runs them down the wall. On a stained house they mostly disappear into the colour. On a painted or very light-stained house they show, and the fix is a stain-blocking primer under paint, or on stained siding, cleaning the streaks with a brightener and sealing the end grain and nail heads. New cedar bleeds the most in its first winter, which is another reason to get the first coat on before the rain starts.

Cedar decks and fences on the same cycle

Most houses with cedar siding have a cedar deck or fence too, and they age faster than the walls because they are horizontal, in the open and in contact with the ground. A deck floor wants a maintenance coat every two to three years and a fence somewhere between the deck and the siding. Doing them in the same season as the siding keeps the colour consistent and saves a second setup. What deck prep involves here.

Cedar questions