Western red cedar has a good claim to being the best timber for garden furniture in Britain. It is light enough to shift around single-handed, stable enough to stay flat through a wet winter, and full of natural extractives that resist rot without any help from a tin. What it will not do is stay the colour you bought it. Whether it settles into a warm honey-brown, a soft silver-grey, or a cracking patchwork depends on what you put on it — and on whether you put anything on it at all.
The UK climate is hard on finishes in a specific way. It rarely gets extreme, but it stays mild and damp for months, then hits the wood with strong low-angle sun in spring and a humid, still summer. That cycle encourages algae, surface checking and, on the wrong coating, premature failure. There are four sensible routes, and each one asks something different of you.
Leaving Cedar Bare
This is the lowest-effort option and, for many people, the right one. Left alone, cedar starts out a rich reddish-brown and silvers within a year or two, depending on how much sun and rain each face gets. The greying is caused by UV breaking down lignin at the surface. It is a cosmetic change, not a structural one.
Expect uneven colouring as it happens. Rain-washed faces go grey first while sheltered corners stay brown, and any spot in shade or against a wall will grow green algae and dark mould. Small surface cracks — checking — are normal on cedar outdoors and mostly harmless, particularly on thicker sections.
Bare wood asks only for an occasional scrub with a stiff brush and water, or a mild detergent if algae is stubborn. The catch is that once cedar has fully silvered, no clear oil will bring the original colour back. If you want the warmth, you have to add pigment.
Penetrating Oils
Tung oil, Danish oil, decking oils and the various "teak oil" blends soak into the surface rather than sitting on it. Because there is no film, there is nothing to flake or peel, and the timber can still take on and release moisture as it always would. The grain darkens and deepens, and cedar looks noticeably richer within minutes of the first coat.
The limitation is UV. Clear oil slows water uptake but does very little about sunlight, so an oiled piece will still drift towards grey unless the product contains pigment. Most oiled furniture needs a fresh coat at least once a year, and horizontal surfaces — a table top, an armrest — often want two.
Two practical points. Cedar's natural oils can slow the curing of some finishes, so apply thin coats, wipe off what has not soaked in after twenty minutes or so, and let each coat dry properly before the next. And read the label: some cheap products are mostly solvent with a token amount of oil, which is why they seem to vanish after a few weeks.
Coloured Stains
Pigment is the only genuinely effective sunscreen for outdoor timber. A semi-transparent stain still lets the grain read clearly, but the pigment particles absorb UV before it reaches the wood, which is why stained cedar holds its colour far longer than oiled cedar.
Water-based stains dry fast, smell mild and clean up with water, though they can raise the grain slightly on the first coat. Oil-based and solvent-borne stains penetrate more deeply and give a warmer, slower-building colour, at the cost of a stronger smell and longer drying times. Solid stains cover almost like paint; they are a decent rescue for a piece that has already weathered badly, but they hide the very thing you bought cedar for.
New cedar can be reluctant to take a water-based stain evenly. A light sand with 120-grit, or the pre-treatment the manufacturer recommends, opens the surface enough to help. Always test on an offcut or the underside of a rail first.
Varnish and Other Film Finishes
Spar varnish, exterior polyurethane and yacht varnish all work the same way: they build a film on top of the wood. Done well, on the right piece, nothing looks better. Done carelessly, or on a south-facing table, it is the finish most likely to disappoint.
Cedar moves with the seasons. A rigid film does not move quite the same way, so hairline cracks appear, water gets in, and then cannot get out. The result is black staining under the film and peeling in patches that are tedious to repair. UV degrades exterior resins as well, which is why varnished furniture needs a fresh maintenance coat every year, sometimes less.
If you choose this route, use a flexible exterior varnish with UV inhibitors, apply several thin coats with a light sand between each, and accept that you have taken on an annual job. It suits a sheltered chair on a covered porch. It is a poor match for a bench sitting in the open.
Choosing Between Them
- Bare: least work, natural look, goes grey and patchy. Best for planters, slatted screens and anyone happy with silver.
- Oil: warm colour, no peeling, annual recoating. Best for furniture you will handle each spring anyway.
- Stain: longest-lasting colour, good UV and algae resistance, two to four years between coats. Best all-round choice for exposed furniture.
- Varnish: highest gloss and best water shedding, highest maintenance and greatest failure risk. Best for sheltered, decorative pieces.
Preparation Decides the Outcome
- Work on a dry day, in shade, with the wood surface between roughly 10°C and 25°C. Direct sun makes finishes flash off and dry unevenly.
- Sand along the grain with 120-grit, then 150 if the surface feels rough. Do not polish finer — very smooth cedar closes up and takes oil poorly.
- Brush or vacuum off dust, then wipe with a damp cloth and let it dry.
- Seal end grain and any drilled holes with extra coats. End grain drinks finish and is the first place water gets in.
- Apply thin coats rather than one thick one, and follow the recoat window on the tin.
- Use stainless steel screws and fixings. Cedar extractives react with iron, leaving black stains that no finish will hide.
- Lift furniture off paving with rubber feet or small blocks so air can move underneath.
A Workable Routine
For most gardens, a semi-transparent stain on exposed surfaces with oil on anything you want to keep lighter in tone covers the ground well. Set aside an afternoon each spring: wash the furniture with a soft brush and mild soap, let it dry, sand any grey patches lightly, then recoat. Ten minutes per chair, once a year, keeps cedar looking deliberate rather than neglected.
Whichever finish you pick, buy a small tin first and test it on the back of a leg. Cedar varies from board to board, and what looks right on a sample chip rarely looks the same on a whole bench. Solvent-based products need ventilation and careful rag disposal, so follow the maker's instructions — and if you are unsure how a product behaves on your particular piece, ask the supplier before you commit.
Photo: ready made / Pexels
