Can I attach aluminium fly screen directly to the top of a pergola?

[miriberry]

Hi, I am wanting to net the top of a pergola to protect grapes and aprcots from birds.  I thought maybe I could put do it with aluminium fly screen instead of fruit net.  It is an old wooden frame pergola and I am in a high BAL rating area (either 19 or 29) but the pergola was built before Bal ratings.  My house is wood and stone.  I was hoping perhaps the fly wire could also offer better ember resistance than the plastic fruit netting?  The frame has battens and joists across with approx 800- 900mm centers.  Do you think fly wire would allow water through adequately.  Would this work?  Thanks, Miri

[Dave-1]

Good evening @miriberry 

Wow love your question! Its something I have heard about and kinda had in the back of my mind but havnt really thought it through.

Definently will let the more knowledgeable people help you out with this question Any chance you could post a couple of photos to help us out?

You start of question caught my eye as I want to use something to protect my blackberries that isnt a nylon style net. I was going to sugest a chicken wire covering but your BAL has thrown that out. I love the idea of something doing two jobs. 

Paying attention for sure.

Dave

[EricL]

Hello @miriberry 

Welcome to the Bunnings Workshop community. It's marvellous to have you join us, and thank you for sharing your question about using flyscreen on your pergola. 

I believe it should work just fine seeing that the gap for aluminium flyscreens ranges around 2mm. It might slow down the rainwater, but it will not stop it from coming through especially if it is a strong deluge. In regards to the BAL rating, please keep in mind that the test was probably conducted while the mesh was vertical. I'm not sure if it still applies when installed horizontally.

It would definitely stop the birds from coming through. Just keep an eye out for other points of entry along your pergola. I suggest using a treated timber moulding such as 18 x 8mm 5.4m Moulding H3 Treated Pine FJ D Mould Clear LOSP as a cap to hold the flyscreen in place in combination with Paslode 40 x 2.5mm 500g Griplock Galvanised Nails. Remember to drill pilot holes when using this.

I'll give our supplier a call tomorrow and double check for you.

If you have any other questions we can help with, please let us know.

Eric

[MitchellMc]

Hi @miriberry,

Our aluminium flyscreen is suitable for BAL-29 and complies with AS 3959-2018 Resistance against increasing levels of ember attack, with increasing heat flux. I've contacted the manufacturer, and whether the flyscreen is used in a vertical traditional orientation or horizontally makes no difference to that rating.

So, in answer to your question, it would offer better ember resistance than plastic fruit netting.

Please let me know if you have any questions.

Mitchell