Pergola build Green oak

Just want to pick some brains on a pergola build I am going to attempt using green oak / fresh oak timber . I want to use oak for longevity and green oak cause its much cheaper than dry oak

I putting it up the side of the house it will be freestanding can't be attached to house , it will be a rectangle shape spanning 16ft in total length, 1ft will be over hang on either side and 8ft wide . I am planning on using 6x6 posts for the legs they be six in total two in the middle and 4x4 for the beams connecting the legs together and using 4x4 again for the rafters. Each individual pieces of wood will be 8ft long except wind braces
I do want the chucky look hence why 6x6 and 4x4 timber

Look a bit like this but with less rafters


The beam will span about 6ft 2 inch give or take between the legs do you think 4x4 beams will bow badly ? I wasn't going to bother with wind braces but seen as it will be free standing it should help keep its shape , I haven't added the wind braces into the 6ft2 total . And how would you attach the beams to the posts? Thought about just doing a simple notch out right through the middle of the 6x6 post ( like a U shape or L shape ) and sitting the 4x4 beam right through it and maybe a half lap joint for where the beams meet for the middle legs , consider maybe a large dove tail joint in the middle leg section as well but is this over the top? Another thing the rafters will be connecting each side of the pergola together like the picture above and the rafters will be sat on top of each post so any dovetail / lap joint or just butting up the to beams shouldn't be visible and better protected from the weather . Thinking of just using 7 rafters 3 on top of posts and 2 in each bay section I may up this to 3 if it doesn't look right .

I wouldn't mind doing a bit of traditional joinery but I am likely to use A4 stainless steel coach screws as well, I've chickened out on doing tenor & mortise wind brace joints , I've had a few practiced runs which went ok ish its the angle what puts be off, I don't feel comfortable risking messing it up and the amount of time it takes doing T&M joints . I am not a joiner but don't mind a dabble

So I am asking will 4x4 beams and rafters bow badly and what sort of joints should I use .

 

An awful lot of questions there @Perki most of it sounds like you have put a lot of thought into it and like you are approaching it in the right way.

As for timbers sagging, it will happen to some extent any way and green oak is surprisingly heavy but much softer to cut.
A chain saw could be handy and a decent chop saw.
You definitely need the bracing to keep it rigid and it makes the appearance more rustic and traditional.
I've built similar things, mostly porches, where I last worked , some halving joints where possible, without the right gear mortice and tennons can be pretty time consuming, i guess you could just butt the braces if you want and use the coach screws to hold them.

 

Thanks @shiney that's very helpful. It quite a grand pergola you have and weathered nicely it would cost a small fortune now around £6500 -£7000 doing a quick quote on google . The Oak pegs look faux to me but effective ? might be something I will consider doing

I've reckon the cost of timber for my own build will be around £500-600 buying the timber from Luxury wood, I don't have anywhere local that supplies green oak hence why I don't want to mess it up delivery alone is £100. I don't like spending a large amount of money on something I haven't seen but what can you do .

@pete yes to many questions its all rolling around in my head, think I maybe over complicated it and not keeping it simple. It is after all to grow plants on so that will cover up my shoddy joinery and to distract from the pebble dashed wall I don't like.

He made much easier work on the T&M joint than me @Loofah that chisel is a beast wouldn't mind one of them . I were doing full shoulders on my t&m which were making it difficult to get perfect.

I did want to be a joiner originally when I was a young whipper snapper, they had course at school for all sorts of trades work but only destructive kids or not book smart kids got sent on them courses which didn't go down well with me and others, what are we short of now Tradesman

 

I'm guessing that you have checked out timber suppliers in your area Perki, even ask a few local sawmills or fencing suppliers.
Even if they can't supply they should know someone who can.
If you really want to use mortice and tennons with dowels you could hire a portable chain morticer, it would save a lot of work.

 

One quick question before buying wood ( still can't find anywhere local who supplies it ) it states on the website that it is landscaping grade it says

These posts are Landscaping Grade and will have splits, knots, and bark and may deviate from the specified measurements. Only in exceptional circumstances will we replace or refund delivered stock.

Landscaping oak is sold "green" and requires specific joining techniques to manage movement in situ. If you are unsure, please consult a professional green oak joiner .

Its not classed Structural grade oak , although a pergola is a structure in a sense it not like barring heavy loads like a roof / house . I am not particularly bothered about knots or doing a bit of sanding or planing if needs be . I can't see why it can't be used for pergola what you reckon ?
I am adding 2 extra rafters as well, after layiny some wood out it didn't quite look right .

I did spot the nest eventually @shiney took a while .

 

My experience is you can get green oak which is basically sawn up tree trunks recently cut, and you can get air dried, again mostly for outside work but dried to as low as its likely to get without kiln drying.
Sizes will vary with green stuff and it will be rough sawn, you dont sand this kind of stuff or plane it, you use it as it comes and the rough surface is part of the charm.

I'd not worry its not structural grade as that really only applies to getting involved in building regs so maybe restoring old buildings etc.

 

Thanks Pete that's what I thought mind at ease . They is a massive increase in price in dried wood around 4x plus .

 

Yes I suspect there would be, but assuming you want something a bit rustic looking the defects, as you say, and any twisting and warping that will happen will only add to the charm of the pergola.
It also means that to some extent you dont have to worry toooo much about how things fit, as if they fit when you do them today you can be assured they wont fit tomorrow.

Be prepared for all your steel tools to go black and rusty and your hands.

 

I do want the rustic look , no measuring done on paper until the wood here I usually go to the millimetre which will not work with this project. I'll probably just bang it together and hope it doesn't fall down . I've read it shrinks in width mostly but not in length

 

Timber doesn't shrink in length, it only shrinks in thickness/width, and it shrinks greatest along the annual rings, so something that is square in section to start often ends up slightly diamond shape.
But it this case that is not really an issue.