Oak framed orangery

Spirit_2

We are replacing a rather tired flat roof extension with an oak framed orangery. We have had a four firms in to quote. We are looking for a frame supply and full construction including any brickwork and internal finish.

The suppliers have offered timber as follows.

2 have air dried oak frames
1 has green oak frames and coated aluminium framed glazing
1 has green oak frame and kiln dried oak framed glazing.


Each supplier has advocated for the type of timber they use.

Cost wise the air dried oak is a lot more (about £60,000 more). We will pay it if it is worth it. The trouble is we don't know if it is or it isn't. They can tell us anything
.
Has anyone got any experience of these types of timber?

Furts

A general suggestion is it depends what style of building you are trying to achieve. Think along these lines. Green oak will be wet/fresh oak so when you build it will gradually dry, move, and create feature like a Tudor building. Hence, any windows or brickwork need careful thought - they should not be moving with the frame.

Air dried oak should be more stable - but it really depends how long the oak has been drying. In theory this means you could build in a more conventional way putting a skin of brickwork up the outside. I am surprised this costs an extra £60K just for sitting around drying, but just like fire logs the longer it seasons the more it costs.

With the figures you are paying it could be prudent to seek specialist advice - there are oak frame specialists/consultants and conservation folks out there. Be careful - a family member was going down this route and gave up because he felt nobody knew what they were talking about from oak frame companies, to architects and to structural engineers.