Advice on modern style green Oak pergola

[mrmoose]

Hi Folks
Not having worked with green Oak very much I am looking for some advice on constructing a set of modern style green Oak pergolas to replace a customers set of existing structures in pine that have been up for apparently 20 years. (Please see photos).
The existing timber is 75mm square and the structures are 2.35 m tall
My concerns about taking on the project are:

The type of joints on the existing are a bit unusual and I believe might be so in green Oak
She wants the same style so no bracing.
The overall look as she would like the Oak a bit thicker maybe 100mm
Whether they might twist, warp or not be very straight.
How long they would take to rot in the ground (I guess I could use a stainless steel foot of some kind.)
I look forward to your advice.

 

[bjm]

Might be worth getting hold of a copy of this TRADA book on Green Oak

 

[Blackswanwood]

Checkout the Youtube video by the Restoration Couple on making an Oak Pergola - it demystified a lot of things for me on oak framing.

Sitting the legs on staddle stones keeps it off the ground and means it will last much longer.

 

[RobinBHM]

maybe concrete posts in the ground but use postsavers

Ive used flashband with a hot air gun and followed by a wallpaper seam roller.
massively increased life span

 

[TheUnicorn]

Checkout the Youtube video by the Restoration Couple on making an Oak Pergola - it demystified a lot of things for me on oak framing.

Sitting the legs on staddle stones keeps it off the ground and means it will last much longer.

I assume you mean...



I think they were pretty lucky, not a lot of health and safety (yawn), if one of those beams (or more) came down on top of you it would hurt and then some. I'd want a lot of manpower, scaffolding, bracing, whatever I could get to keep everything upright and controlled until the last peg was in place.

I put together an oak sleeper garden edge a couple of months ago, so twice the thickness of the proposed beams, they were bloody heavy, and hard to control even at ground level.

 

[Blackswanwood]

Yes - there is a series of them which gives a lot of detail.

I don't recall being alarmed by the H&S- were they working in the main with 8" timber when you are looking a 4" which will be easier?

 

[TheUnicorn]

maybe concrete posts in the ground but use postsavers

Ive used flashband with a hot air gun and followed by a wallpaper seam roller.
massively increased life span

I like the look of those postsavers, not come across those before. I replaced a post that had rotted out in a metpost, at least five years ago. Like you I surrounded the base of the post with flashing, so the water runs off and onto the ground without being held wet. I repainted the post recently and it is solid as a rock. In the case of the oak pergola I'd raise it onto staddle stones, pinned from beneath as per the video. The only addition I'd make is to route a drip strip or recess on the foot of the post so the water has no ability to sit on the underside

 

[mrmoose]

Thanks so far folks, yes I have seen those postsavers, they look quite good. I've used plastic bin bags and gaffer tape in the past to good effect too I don't think saddle stones will go with the style. Any thought on the joints? also, I'm concerned that using 4-inch posts might make it look too clunky for the modernist style.

 

[mrmoose]

I assume you mean...



I think they were pretty lucky, not a lot of health and safety (yawn), if one of those beams (or more) came down on top of you it would hurt and then some. I'd want a lot of manpower, scaffolding, bracing, whatever I could get to keep everything upright and controlled until the last peg was in place.

I put together an oak sleeper garden edge a couple of months ago, so twice the thickness of the proposed beams, they were bloody heavy, and hard to control even at ground level.

Many thanks, I had already seen that vid. Of course, this project will be smaller sized timbers. Still haven't decided whether to pursued the customer to stick with 3-inch oak

 

[mrmoose]

Cheers! I

Might be worth getting hold of a copy of this TRADA book on Green Oak

Cheers! I will if I get the job!