Oak greenhouse base rotting advise needed

[womble]

A couple of years ago I put a greenhouse on an green oak sleeper bed, I was advised that it would last for 10 years, which will be fine for me.
But yesterday I was out clearing out some earth to refresh the beds and noticed the back wall of the base is rotting on the inside, there was a big ants nest there, not sure if they caused it, or are there because of it.
Although I didn't want to, I am now going to paint the inside face and the top with creocote, then dig down the outside face and paint that as well. I can't paint underneath it, for obvious reasons.
I'm also wondering if I should dig right down and have the base on top of the soil, instead of lying level with it.
If I painted the wood I wouldn't grow anything in it till Spring.

Any advice or questions that spring to mind?

[Jeanied]

Hi Womble - watching your question with interest as I have raised beds in my garden made from green oak sleepers about 6 years ago and they are rotting away slowly too - no way can I treat them as I can't get to most of the surfaces. I think I'll just have to get some professionals in to re-do them but it is going to mean large scale destruction and some big expense and disruption.

[tamsin]

I would think on top of the soil would make them less prone to rotting as they'll dry out more. When you come to redo it in future putting them on a bed of sand/gravel to improve drainage underneath might help too.

[Jeanied]

Have done a bit of a search since reading these posts and I think there are a couple of - first to paint the timber with a preservative and second to insulate the face of the timber with a liner - have a look and see what you think.
Error - Rated People
sorry the link has turned up an error - what I googled was green oak timber preservation - they all empasise keeping the wood dry which is where I have gone wrong.

[womble]

they all empasise keeping the wood dry which is where I have gone wrong.

Yes, although it sounds silly, I didn't think green oak needed to be kept dry, I will have to dig out the soil around them I think and put preservative on them.

tamsin, I put them on a bed of sand, thanks for your help.

[Madasafish]

I use a mixture of used engine oil and creosote and apply by brush. The edging planks on our garden have now been in place for 22 years. prior to that they were planks for a garage door. Repaint every 5-10 years when I feel like it/weather is good/they look like they need it.