Thread: Advice for trellis

Hi, and welcome to the forum.
It sounds like your on the right track and is the way I would do it. The 50x50 will do you for that job, you could go to 40x40 it depends on the weight of your vine that you are going to grow through it. Having 1.5mtr's in the ground will help a lot as well.

Dave

Hi Dave,

Thanks for the welcome and the quick reply. Midalia Steel has a special on at the moment so I can get 6.5m 50x50 lengths for $38 a piece. 40x40 are $29 so even better if I could get away with it. I can use the offcuts as supports for rebuilding my timber planter boxes, for which I should've seeked help on these forums before I started.

Are you putting in a bar/tube across the top as well? Can see the 2 outer ones bending inwards when you tension the wire up and more so after the vine has grown a bit and puts more weight on the wires.

How many wires and how tight are you planning on pulling them?
You might like to thread something like 25mm pipe on one of the wires about 1/3 from the top to stop you bending the end poles in.
Stuart

I'd definitely considered the cross pieces. I have plenty of timber about - I was considering bolting 2.4m lengths of 70x35mm pine across the top of the posts. Stain them to match the rest of the yard and it should look pretty good.

Jeckyll and Hyde just posted (although I can't see the post above) that I should be using SHS with 3mm wall thickness instead of 1.6mm due to the large amount of flex. I did test the flex on 6.5m lengths of the 50x50 and 40x40. While it was certainly noticeable, I am using much shorter lengths. Plus, 3mm 40x40 is $57 for an 8m length. Much more expensive and much more wastage. 2mm 40x40 is $45 per 8m length, so that is less to bear, but most others haven't mentioned the flex as a problem except for the end posts.

Originally Posted by Stustoys

How many wires and how tight are you planning on pulling them?
You might like to thread something like 25mm pipe on one of the wires about 1/3 from the top to stop you bending the end poles in.
Stuart

There's an idea. Much less work that bolting on timber cross-pieces. I have no idea how tight the wire is going to be. I am going to play it by ear as the climber grows up. If the wire starts to sag I will re-tension.

I was going to run wire every 250mm or so. That should be heaps to train up the climber. Not sure what gauge to use since the spans will be 2.4m.

Hi,
I have some here and 50x50mm is pretty stiff, they use it for posts some colourbond type fencing as well. I would say the flex over 3mtr's for 50x50x1.6mm would be around the same or less than 40x40x 3mm so save your money.
If your going to strain it I would recommend at least one cross bar like Stuart has said, Two would be better one near the top and one around the middle for that many wires. Strained wire does put a lot of force on the posts, then you have the weight of the vine on top of that.
I worked for a fencing contractor years ago doing mostly chain mesh fencing, and it doesn't take much tension to pull a post over, and at 3mtr's, it has a lot of leverage.

The timber sounds good to brace the posts, and like you said will match the rest of your yard.
If you decide to go pipe, another way you could attach the pipe is to drill a hole through the square on both uprights and put a long bolt in each. The bolt could then go inside the pipe to hold it in place and after tensioning it wont go anywhere.

Dave

Are the posts going to be Galvanised?

The pipe is a good option, Dave. I'll have to see how I feel once everything is up. I have 11 posts to dig holes for so that will take it out of me. Thanks for the feedback with the 50x50x1.6. I feel pretty confident of its strength after checking it out.

And yes, the steel is galvanised - electroplated. I will also buy capping to put on the top end so the posts don't fill with water. Depending on the look I may get the missus to prime and paint them to match the fence colour.

Getting paint to stick to is hard, I have painted it myself and it ends up flaking off. If you do paint it leave it for a few months to weather and you will have a better chance of it sticking.
Another alternative is to use the colourbond square tube they sell for fencing posts and carports etc, it comes in a lot of colors. See if the steel place has it or can get it in for you, or go to a fencing or carport/shed shop for it.
It may be a little more expensive but if you take the paint cost into account it wont be much if any more and will last for years.

Dave

Originally Posted by nayler

The pipe is a good option, Dave. I'll have to see how I feel once everything is up. I have 11 posts to dig holes for so that will take it out of me.

If you can work out where the pipes will be, and where you need the holes, it will be easier drilling them before on the ground before putting them up. Saves being up a ladder drilling holes, especially with fresh concrete.

Dave

I was originally looking at primed SHS instead of gal:

50x50x1.6mm gal = $38 per 6.5m length
40x40x2mm primed = $45 per 8m length (lots of wastage)

Would be nice if they had primed 6.5m length, but they only come in 25x25x2mm.

I think if the right primer is used then the paint should stick just fine. It only needs to last a few years while the climber does its job.

I did look at the Colorbond tubing but it is significantly more. Like $62 per length for 76x38x1.6 - lots of flex in one direction.

As for drilling up the ladder - not so concerned. I'm more concerned about getting the damn posts in the holes without them caving in. The sand is so soft here. Water helps, but sometimes it just delays the cave-ins and makes them more spectacular.

Why not make it out of treated pine instead of steel? Yopu won't have to worry about it rusting then.
As a plant consider a couple of passionfruit vines. they will fill in the trellis so you can't see through it and you get to have plenty of fresh passion fruit when in season. If you plant 2 or more different varieties you get different fruit as well.
bollie7

Originally Posted by bollie7

Why not make it out of treated pine instead of steel? Yopu won't have to worry about it rusting then.
As a plant consider a couple of passionfruit vines. they will fill in the trellis so you can't see through it and you get to have plenty of fresh passion fruit when in season. If you plant 2 or more different varieties you get different fruit as well.
bollie7

Rust or rot - which will come into play first? For strength, I'd be more inclined to go for the steel. I did look at treated pine, but I'd either have to use stirrups, which only secure the post right at the bottom; or long posts, which can be hard to find. Either way - $$$$.

We have 24 metres of trellis to populate, so we are looking at a lot of options. About 17 metres is in full sun all day, and the other 7 is stuck down the side of the house with midday sun for a few hours.