Wood seal flaking off fence

[d000hg]

I had my wooden fences painted with a standard water seal/stain earlier this year - Ronseal Dark Oak I think. Some of our fences had previously been done, others appeared to be raw wood that had weathered a fair bit.

It went on well and appeared to be soaking in very nicely. But within weeks, we noticed it had started to flake in a few places... in a kind of mottled fashion like where you have sun-burn and your skin starts to peel. Where it's come off, you can see the bare wood underneath.

I find this confusing since if it soaks into the wood, how CAN it flake off? Even if the top layer flaked off, the wood underneath would still be stained.
We wondered if the seemingly untreated wood actually had some sort of sealant on which is making it non-permeable?

I re-applied to affected areas but again after only a month or two it is coming off in the same way. Should I keep at it, or what? It's supposed to last for 5 years!

 

[JohnD]

If it is a typical water-based shed and fence stain, it doesn't soak in. It leaves a water-repellent waxy film on the surface.

Did you scrub off mould, algae and dirt from the wood before applying the stain? Bad algae or moss needs bleach to kill it, then a stiff brush. Ordinary dirt comes off with a broom and a hose.

A power jet-washer is very good for getting fences clean before staining.

New garden timber is sometimes treated with a preservative, but this weathers off the surface in a few months enough so you can stain it.

 

[d000hg]

I think it's this stuff, or very similar: http://www.cuprinol.co.uk/products/5_year_ducksback.jsp

If it sits on top that would explain how it can flake off. Not sure about the preparation that was done as I didn't do it. It sounds like giving a quick sand to the flaking parts and re-applying would do the trick?

 

[JohnD]

it's very difficult to sand a fence, which is not smooth or flat. Try a stiff nylon brush or broom.

Or a jet-washer if you can lay your hands on one.