Cedar Shakes and Shingles

Cedar has been a premium exterior material for generations, and the affection is earned. It's dimensionally stable, mildly insulating, and rich in natural oils that fend off insects and decay. Left to its own devices it weathers to a soft silver-gray that many people prize. But under the romance, cedar is still wood: a living, porous, grained material that swells when it drinks and shrinks when it dries.

That last fact is the whole story. The line between cedar that lasts fifty years and cedar that fails in fifteen is drawn by a single question — how fast does the surface dry after it gets wet? Keep that question in front of you and every care decision, from cleaning to finishing to where you plant a shrub, more or less answers itself.

Wet is fine; staying wet is not

Cedar is water-sensitive in a very particular way. It tolerates getting soaked; what it can't survive is staying soaked. The wood is built to run through a cycle — absorb moisture, then release it — and it depends on that cycle completing. Interrupt the drying half and the material begins to lose the fight. Its natural decay resistance is real but finite, and it fades as the wood weathers and as moisture is held against it.

That's why the cedar that fails first is always the cedar that can't dry: north-facing and shaded walls, poorly ventilated gable cheeks and porch soffits, courses packed with debris, and low sections wetted by splashback. It's also why the placement matters as much as the material. The same shake behaves like a premium siding on a breezy, sunlit wall and like a sponge on a damp, shaded one. Wherever cedar shows up — full wall siding or gable accents, roofing that takes the harshest sun and rain, shaded dormer cheeks, protected but humid soffits, or ground-hugging fencing — the local drying conditions decide its fate. Shakes are thicker and hand-split for a rugged texture; shingles are sawn thinner and lie flatter; but where water is concerned they behave identically, and the difference is only thickness and looks.

Why the pressure washer does the most harm

If drying is the goal, a pressure washer works directly against it, which is why cedar sits at the delicate end of the cleaning scale. Wood is soft and directional. A concentrated stream carves out the softer bands of spring grain, leaving a furrowed, fuzzy surface, and — the real damage — it drives water past the surface into the body of the shake, into exactly the depth that's slow to dry back out. You can create the trapped-moisture problem you're trying to clean away.

Treat cedar as a surface to soft wash rather than power wash. If a machine is used at all, it should be a gentle, wide-fan rinse held well back and kept moving, never a stripping tool; when in doubt, skip the pressure and rely on chemistry and a soft brush. Our overview of pressure washing versus soft washing explains where cedar lands, and because so much cedar care is really wood care, the technique in how to clean a wood deck transfers well.

Cleaning with the grain

A gentle, chemistry-first routine lifts the usual stains — moss and algae on damp faces, mildew spotting, brown tannin bleed on newer cedar, and rust marks around non-stainless fasteners — with the least risk to the wood:

1. Clear debris from courses, valleys and keyways so water and cleaner can't pool.
2. Wet the wood with plain water so it absorbs cleaner slowly and evenly.
3. Apply a wood-safe cleaning solution matched to the stain.
4. Let it dwell briefly per the product's guidance, keeping it from drying on the surface.
5. Agitate along the grain with a soft-bristle brush — never a wire brush, which shreds fibers and leaves rust-prone metal behind.
6. Rinse lightly from the top down, using volume rather than pressure.
7. Let it dry fully before any stain or finish, and test stronger products on a hidden spot first.

Cedar on a roof is a different and more dangerous job. A cedar roof is slick, height-exposed, and easily damaged underfoot, so roof cleaning belongs to professionals with the right footing and fall protection rather than to a homeowner on a ladder.

Graying, greening, and the difference that matters

Not everything on a cedar wall is a problem, and telling the harmless changes from the real warnings is half of caring for it. Graying is the most misread of all: it's simply UV breaking down the surface lignin, a cosmetic silvering that says nothing about the wood's soundness as long as the material underneath stays dry. If you prefer the warm tone, a breathable penetrating stain slows it; if you like the gray, just keep the surface clean. Fine surface checking is likewise normal aging.

The signs that deserve attention are the ones that point to trapped moisture.

Widespread rot, cupping, or shakes lifting off the wall or roof deserve a closer, often professional, look before water reaches the courses behind them.

Giving cedar every chance to dry

Everything productive you can do for cedar comes back to speeding the drying cycle. Sweep debris out of courses and off roofs so water can't sit against the wood. Trim back branches and vegetation that shade a wall and starve it of sun. Keep soil, mulch and sprinklers from constantly wetting the lower courses. Reapply a breathable, penetrating stain periodically rather than letting a film finish fail and peel. Swap out cracked, cupped or rotted pieces early, before water gets behind the neighbors. And use stainless or hot-dipped fasteners to avoid the rust streaking that plain steel leaves behind.

Do that, and cedar rewards you. Well maintained, it's impressively durable for a natural product, though it sits below masonry and metal on the spectrum and depends on care far more than brick or tile ever will. Its practical limit is almost always moisture management: cedar that dries quickly, stays clear of growth, and gets a periodic finish comfortably outlasts cedar left shaded, matted with moss and wet. Neglected, the very same material can decline fast — which is exactly why cedar repays attention more than most surfaces on the house.

Related guides

• Pressure washing vs. soft washing
• How to clean a wood deck
• Painted wood: exterior care and cleaning
• Engineered wood siding
• Asphalt shingles: exterior care and cleaning