How to install Merbau screening panels?

[Louiewooding]

G’day all,

I’ve got 3 50mm x 50mm concreted posts, and 2 25mm x 38mm rails in a single lug attached in between. 
Will attaching 900mm tall, 1800mm wide, 15mm deep Merbau screening panels. I’m attaching about 2.6 worth, or a total of ~57kg (1 panel is 22kg). 
Will these rails be enough? Or do I need to add another 50mm x 50mm rail in the middle? 

[EricL]

Hello @Louiewooding 

Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thanks for sharing your question about your Merbau screening.

Generally speaking, the rails will be able to hold the Merbau screening panels, but it won't be strong enough to hold it with the wind blowing on it. Once a "wind load" is applied to the fence rail it will bend and will not straighten back out. In regards to your suggestion of using adding another post in between the 1800 distance, a mid-post in each 1.8 m bay, that is the best fix because it halves the span and makes the rails stiffer due to the shorter distance. 

Let me call on our experienced members @Dave-1 and @Nailbag for their recommendations.

If you need further assistance, please let us know.

Eric

[Dave-1]

Good Evening @Louiewooding 

I do like how you are building a seperate screen to carry the load of the extra height. I think the span is a little too far to carry the merbau screens. As @EricL has suggested an extra post between each side would stop the sag.

Just wondering what are the foottings of the post going into?

Dave

[Louiewooding]

Howdy Dave,

I think that may be the case, good to hear everyone’s thoughts and opinions.

The current 3 vertical 2100mm posts are concreted in, and attached by double lug 25mm x 38mm fence brackets 

[Nailbag]

Hi @Louiewooding 

Just adding another confirmation of a negatory on adding those screens to the existing fence. Its simply going to bite you and your neighbours down-track with that significant weight and wind sail.

Stand alone is your best option long term.

Nailbag