Help! Green Oak pergola all rotting

[PeticaW]

I am surprised that after 4.5 years my lovely * expensive*! green oak pergola which I had made for my garden, with benches to sit on with storage underneath, seems to be rotting.. It has weathered a lot more than I thought, which is ok, although the floorboards are really cupping, but the worst is the benches - they seem to be falling apart and have mushrooms of all varieties growing inside. I was told not to treat the green oak with anything. I chose green oak because I was told it would last for ages, but it is really looking worse for wear and is almost unfit for purpose if we can't sit on the benches. What should I do?? Helppp!
thanks.

 

[kostello]

Pictures would help here.........

I'm intrigued

 

[Lord Kitchener]

This may be a daft question, but are you sure that it is oak?

 

[Dodge]

Yes photos would be good, was made aware of a similar situation a couple of years ago and the company supplying green oak had actually been using horse chestnut which rotted in a few years and passing it off as oak - Basically a con. At that time there was loads of chestnut about because of bleeding canker and the tree surgeons were chopping them down like there was no tomorrow!

HTH

Rog

 

[zb1]

If it is oak it's not European Oak. Dodge is probably right chestnut and beech both look like oak but are not durable outdoors. Where did it come from?

 

[Phil Pascoe]

If it is oak it's not European Oak. Dodge is probably right chestnut and beech both look like oak but are not durable outdoors. Where did it come from?

Chestnut ( sweet ) looks like oak without figure or medullary rays, but is quite durable - it's used for pall fencing. Horse chestnut (conker) is the one affected by canker, rots quickly and doesn't even make good logs, let alone anything else.

 

[PeticaW]

oh! I'll get photos tomorrow it's too dark now. It came from a shop called uk-oak, in total the timber cost around £800 . I might be able to attach a photo of what it looked like when new!
Oh - annoyingly it says my account is not allowed to post links and my photo is too big - *yawn*.
back tomorrow. thanks!

 

[CHJ]

See The Picture posting Guide at the top of the forum page.

 

[zb1]

If it is oak it's not European Oak. Dodge is probably right chestnut and beech both look like oak but are not durable outdoors. Where did it come from?

Chestnut ( sweet ) looks like oak without figure or medullary rays, but is quite durable - it's used for pall fencing. Horse chestnut (conker) is the one affected by canker, rots quickly and doesn't even make good logs, let alone anything else.

Sorry that should have read "as durable outside" Both sweet chestnut and beech are and have historically been used in buildings and outdoor structures. Beech is a rotter though. You see bottom plates made with beech dissolve. If the timber that has been used is sweet chestnut, or to a slower rate oak, and they have used very sappy, cheap cuts of timber you would end up with some fungus and rot.

I can't see a company like that not selling you oak when you paid for oak, I haven't dealt with them though so can't comment really. What is the timber sat on? Where is the rot concentrated and was there any evidence of fungal attack in the timber before it was worked. I occasionally have to reject timbers with brown rot in. Lovely for furniture and veneers, not so good for building houses with.