Do you need to finish cedar?
Not always. Cedar is naturally resistant to decay and insects compared with many woods, so it can be left unfinished outdoors, where it will gradually weather to a silvery gray. Many people prefer to finish it anyway to keep the color, slow weathering, reduce surface checking and limit mildew. Indoors, a finish protects against stains and handling, though some people leave aromatic cedar bare to keep its scent.
The right approach depends on where the cedar is used and how you want it to look.
Know your cedar
- Western red cedar is the typical choice for siding, fences, decks, pergolas and outdoor furniture. It is soft and takes stain well.
- Eastern red (aromatic) cedar is often used for closet lining, chests and small projects, and has a strong scent. A heavy film can seal in or reduce the fragrance.
- Other “cedars” (such as Spanish cedar or Alaskan yellow cedar) differ in color and oil content, so check the supplier’s finishing advice.
Prep and safety
- Dust. Cedar dust can irritate the eyes, nose and skin, and some people are sensitized to it. Wear a well-fitting dust mask or respirator, eye protection and, with power sanders, hearing protection. Use dust extraction and ventilation, and clean up with a vacuum rather than blowing dust around.
- Acclimate the wood to the environment where it will live for a few days before finishing.
- Sand with the grain. Moderate grits are usually sufficient for stain and oil to absorb well. Over-sanding can burnish the surface and reduce absorption of penetrating finishes. Rough-sawn surfaces typically take stain well and are not sanded.
- Remove dust with a vacuum and a tack cloth or a slightly damp rag.
- Seal knots. Resinous knots can bleed through a finish. A shellac-based primer is commonly used to seal them before painting or staining.
- Use corrosion-resistant fasteners. Cedar contains natural extractives that can react with plain steel fasteners, causing dark streaks. Stainless steel or suitably coated exterior fasteners are generally recommended.
- Keep solvent-based products away from ignition sources, and treat rags with oil-based finishes as a fire risk (see below).
Outdoor finishes
Penetrating, non-film stains with UV blockers. Commonly recommended for decks, siding and fences, as they tend to fade gradually instead of peeling. Transparent and semi-transparent options show the grain; pigments add UV protection.
Water-repellent sealers. A clear sealer limits water uptake, but clear products offer less UV protection, so the wood may still gray over time.
Letting it weather. Leaving cedar unfinished is a legitimate low-effort choice. Expect color change, surface checking and possible mildew in damp areas.
Cautions
- Plain oils such as raw linseed or teak oil are sometimes discouraged outdoors because they can encourage mildew unless the product has mildewcides and UV inhibitors. Check the label for exterior use.
- Film finishes like standard varnish may crack and peel under sun and rain on exposed cedar. Exterior spar varnish is designed for flexibility and UV, but needs maintenance (see best varnish for wood).
- Paint and solid stain are possible, with cedar-appropriate primers (some stain-blocking primers address tannin bleed).
For the wider picture on water protection, see how to waterproof wood. If your cedar is a deck, the trade-offs in deck paint vs stain and the upkeep advice in treated wood deck maintenance are broadly relevant, though cedar is not pressure treated.
Indoor finishes
- Shellac keeps cedar light and works as a sealer for knots and resin.
- Water-based polyurethane gives a durable, clear film with low odor and little ambering (see whether water-based polyurethane darkens wood).
- Oil finishes such as tung or Danish-style oils bring out the reddish tones and are easy to renew.
- Wax is a light touch for decorative pieces.
- For closets and chests where scent matters, use the lightest finish possible, or leave interior surfaces bare.
Always check compatibility, and test on an offcut.
Getting a “cedar” color
If you want the look of cedar on another wood, semi-transparent stains in cedar or natural tones are widely sold (see water-based vs. oil-based wood stain for choosing a base). Test on the actual wood, since color depends on the species, grain and number of coats. You can also use a cedar-tone stain on cedar to refresh faded areas.
Application steps
- Choose a dry day within the label’s temperature range.
- Clean the surface and let it dry.
- Seal knots and repair damage.
- Apply the first coat with a brush, pad or sprayer, working with the grain and keeping a wet edge.
- Wipe off excess penetrating product as directed; do not leave puddles.
- Add further coats per the label.
- Let it cure before heavy use.
Fire safety: rags and applicators soaked with oil-based finishes can self-heat. Spread them flat outdoors to dry, or put them in a sealed metal container with water, away from buildings.
Maintenance
Wash cedar occasionally with mild soap and water to remove dirt and mildew. Renew penetrating finishes when the surface looks dry or water stops beading. Clean and lightly prep before recoating.
FAQ
Do you need to seal cedar wood? Not strictly, but a finish helps manage weathering, mildew and moisture, particularly outdoors.
What is the best sealer for cedar on the outside? A penetrating, exterior-rated stain or sealer with UV protection is the usual recommendation.
What are the different finishes available for cedar? Stains, water-repellent sealers, oils, shellac, polyurethane, varnish, paint and solid stain, each with different suitability indoors or out.