Seven Years On: Our Experience Preserving Cedar Cladding with UV-Oil
Published: 28 June 2025
Reading Time: 3 minutes 40 seconds
When our extension was built seven years ago, we decided to clad it externally in Western Red Cedar. We loved the warm reddish tones of the newly fitted boards and wanted to maintain that fresh-cut appearance for as long as possible. So, as the cladding was being installed, we applied Osmo UV-Protection Oil Clear.
We’ve written about our experience over the years, and now feels like the right time to bring those insights together into one helpful guide.
Cedar Cladding Will Naturally Weather to Silver
Western Red Cedar is a popular cladding choice for garden rooms, annexes, and extensions thanks to its natural durability against rot, insects, and fungal attack, as well as its rich colouring. However, if left untreated, it will gradually weather to a silvery grey.
This colour change is a natural process caused by UV exposure and moisture. It doesn’t affect the structural integrity of the timber — Western Red Cedar has a maintenance-free lifespan of 20+ years. The change is purely visual.
Some people love the aged silver look from day one, while others — like us — want to slow the weathering and enjoy the original tone for longer.
Many garden room companies offer Western Red Cedar as a cladding option, and some of them also offer UV oiling to help slow the weathering process. This is normally an optional extra specified at the design and ordering stage, allowing the company to either source Cedar pre-oiled in factory conditions or arrange for the on-site team to oil each board before installation.
Our Initial Experiment
Back in 2018, as our extension was being built, we decided to test the effectiveness of Osmo UV-Oil. From one length of Cedar, we cut three offcuts:
- One was stored in a dark shed to act as a control.
- Two were placed outside on a south-facing wall, with two coats of UV-oil applied to one end of each.
We took monthly photos and were impressed by the results. Even after a year, the oiled sections closely matched the control board, while the untreated areas had noticeably faded.
Seven Years Later: How Our Cladding Looks Now
After years of reapplying the oil every couple of years, our Cedar cladding has gradually evolved into a pale honey tone. The treatment certainly slowed the greying process and helped retain a warm mid-tone, which we’ve really enjoyed.
Now, though, some silvering is starting to appear — and we’ve decided to stop oiling and let the Cedar weather naturally from here on.
Why We’re Letting It Go Silver (for Now)
We did consider other options. We tested samples of the tinted Osmo UV-Oils — including the ‘Cedar’ shade — but found it too dark brown for our taste. We prefer the softer mid-tone that natural Cedar develops.
We also discussed staining the whole building black — a finish we’ve used in other parts of the garden, and one that makes a striking backdrop for planting. But for now, we’re curious to see how we like the silvery finish and may revisit the black option in future.
Things We’ve Learned Along the Way
1. Decide to Protect Early
Ideally, the decision to oil should be made during the design stage. Some companies will pre-oil the boards in the factory, ensuring all surfaces — including the tongues between boards — are protected. This can help prevent silver lines appearing if the boards move over time.
2. If You Change Your Mind, Act Quickly
In our case, we decided to apply UV-oil after the boards were installed. The oil was applied within a couple of days. If you change your mind after installation, it’s important to apply the oil quickly — before the boards are exposed to too much light. Think of it like skin without sunscreen — exposure builds up fast.
3. Use the Right Cleaner
We recommend buying Osmo’s own brush cleaner/thinner. We initially tried white spirit but found it didn’t clean the brushes effectively. The Osmo cleaner worked well, and we like to reuse a good brush, so it was worth the investment.
Links to the Products We Used
We’ll include links to the Osmo UV-Oil and brush cleaner on Amazon. These are affiliate links, so we may earn a small commission if you choose to buy, at no additional cost to you.
Disclaimer:
Always test products on a small area before full application, as finishes can vary depending on timber grain and age.
No Regrets About Choosing Cedar
Even as the colour fades, we have no regrets about choosing Cedar cladding. It’s a beautiful, durable material that has weathered well and complements our planting — whether warm-toned or silvery. Its evolving appearance adds character to the building and continues to offer a fantastic backdrop to the garden.
Yes, it’s a premium cladding option — but it’s worth it.
