Garden Pergola

[BAGGIES1]

hi
i've got a very rough plan to build a large pergola at the bottom of my garden. i'm a newbie so open to suggestion..

the area to cover would be 12m wide by 4m deep.

i plan to use 8x 100mx100mx2.6m (or 2.8m) square posts mounted into metal fence posts at the base.

4 posts will span the rear and 4 posts the front across the 12m width.

i will then link each post horizontally with a 4m length. i have yet to determine size but imagine these lengths will run fairly deep as they need to support a 4m gap without bowing.

i have attached an "extremely" rough sketch - apologies in advance but should give you more insight into what i'm trying to do.

i need to determine what width and depth the horizontally running wood lengths should be (connecting the base posts) and the same for the beams running across the top.

all of this is guesswork from someone who hasnt attempted this before so accept my apologies if i sound like i dont know what im talking about - thats because i dont.

but any help/insight would be gratefully appreciated thanks...

Untitled

• BAGGIES1
• 12 Jun 2009
• 1

 

[pantsmachine]

I have in the past built a treehouse climbing frame assault course type thing for the kids in the garden. I used 100/100 square posts. I would guess it spans around 6 mtrs. I have also recently built a 3mtr pergola and used 150mm round posts for it. In hindsight the 100m square posted larger frame looks quite spindly and maybe not in balance? Don't get me wrong its strong about 10 years old and i still go up on top of it no problem. Its just that i think the round thicker posts suit a pergola better. Doubly in saying that i did use square posts for the horizontals on the pergola. Feel free to look at my thread a few below this one. One of the photos shows the view from the pergola down the garden, you can see the treehouse in that shot. Its all down to individual taste of course!

Oh yeah and on my pergola the horizontals are 4"/4" with the thinner cross braces across the top being 4"x2".

 

[Thermo]

50 x 100mm will span and support that distance without bowing, but 50 x 150mm may well look better.

One other comment on your plan. concrete the posts into the ground, dont use met posts as per the drawing. they dont give a decent firm fixing.