Oil or Water-Based Cedar Stain, and How Often to Recoat

The choice between an oil-based penetrating stain and a water-based coating is the main decision you make about cedar, and it sets your maintenance pattern for as long as you own the house. Neither is wrong. They fail differently, and that is what should drive the choice.

How the two behave

Oil-based penetrating stains soak into the timber rather than forming a film on top. As they weather they fade and thin gradually. The important consequence is that they do not peel, so recoating is mostly a matter of washing the surface and applying more. The trade-off is that they need doing more often, and on exposed elevations that can be noticeably more often.

Water-based coatings build more of a film on the surface. They generally hold their colour and their UV protection for longer, so the intervals between coats are longer. The trade-off is at the other end: when a film-forming product eventually fails it can flake or peel, and the preparation to recoat is then considerably more work than a wash.

So the honest summary is: oil means lighter maintenance more often, water-based means less frequent maintenance but a bigger job when it comes due.

Which suits which situation

• Exposed north and west elevations take the most UV and are where any coating works hardest. Whatever you choose, expect these faces to need attention before the sheltered ones.
• Coastal and harbour-facing properties deal with salt as well as UV. Regular washing matters more here than the product choice.
• Cedar you want to look natural generally suits a penetrating oil, because it keeps the grain visible and ages without a hard edge.
• Cedar that is already coated with a film-forming product largely makes the decision for you. Going back to a penetrating oil means removing the existing film first, which is a substantial job.

That last point is the one people are most often caught by. Find out what is on the timber before deciding what goes on next, because switching systems is what turns a maintenance coat into a full strip.

How often

Any interval given as a single number is misleading, because exposure varies enormously between a sheltered south wall and a west-facing gable. The reliable approach is to inspect annually and act on what you see rather than on the calendar.

Signs it is time:

• The colour has visibly lightened, particularly on the sunny elevations.
• Water no longer beads on the surface and soaks in instead.
• The timber feels dry or slightly rough where it used to be smooth.
• Any greying is beginning to show through.

Recoating at that point is straightforward. Leaving it until the timber has greyed and started to break down means sanding back, and in bad cases replacing boards, which is a different order of expense.

What recoating involves

For a penetrating oil in reasonable condition: wash, treat any mould or lichen, allow the timber to dry thoroughly, then apply the fresh coats. Cedar has to be genuinely dry before anything goes on, and after a Wellington wet spell that takes longer than people expect.

For a failing film-forming coating: the loose material must come off, edges are feathered, bare timber is sealed, and then the system is rebuilt. This is where the cost difference between the two approaches shows up.

If it has already gone grey

Grey cedar is not necessarily ruined. The greying is a thin surface layer, and provided the timber underneath is sound it can often be cleaned and restored rather than replaced. Where it has gone further, and the surface is furry or the boards are cupping and splitting, replacement of the worst boards is usually part of the work. That is cedar restoration rather than staining, and we have written separately about the signs that cedar needs restoring.

Getting advice for your cladding

We will look at what is currently on the timber, what condition it is in, and tell you which system makes sense from here. Get in touch, or read more about cedar staining in Wellington.