How to attach Colorbond to a galvanised metal frame?

[Bluejay]

We are getting a couple of large batteries for our solar panels and, as they only have space to go up against the NE side of the house (facing 50 degrees so getting morning - early afternoon sun), I need to make a shade structure for them. I'm planning to weld a metal frame and line the front and top with colorbond sheets left over from a recent re-roofing exercise - and have a few questions about this. 1) Will metal hex head roofing screws self-drill into the material I'm planning to use for the frame (gal1.6mm section square/rectangular tube) or will I need to pre-drill holes? 2) Given I'm only planning to keep sunlight out, and there are lots of air spaces (the side walls and the part of the roof immediately above the batteries will be open to enable passive cooling), is there any advantage in using some sort of sarking under the colorbond walls/roof sheets? If there is what type is recommended? 3) Any other hints/ things I should be considering?

I can't post pics at this stage as I'm just planning prior to battery delivery/installation, and keen to get my design sorted so I'm ready to build when it all happens. However, to give an idea of the scale, each battery is 790w x 1179h x 250d and I need to have  900 clearance above, 200 below, and 600 on each side with the right hand clearance needing to be screened due to where the sun will track.

[MitchellMc]

Welcome to the Bunnings Workshop community @Bluejay. It's terrific to have you join us, and many thanks for your question about attaching Colorbond to a metal frame.

Metal hex screws will self-drill into 1.6mm gal as they're capable of cutting to a depth of around 12mm in mild steel. However, depending on how many you're using, it might save time pre-drilling the holes instead of relying on the screws.

How far will the sheets be away from the batteries? If they are in close proximity, it might be worth adding insulation as a buffer. Although you are sheltering the batteries from sunlight, the sheets will heat up and then radiate heat. If there's an air gap of 30cm, this might not be an issue if there is also airflow. Otherwise, adding some foam insulation will provide some protection.

That airflow is going to be your best insurance against radiated heat. I suggest you make the buffer zone as large as possible and keep the enclosure relatively open.

Please let me know if you have any questions.

Mitchell
 

[MikeTNZ]

Hi @Bluejay,

Why would this need to be made from steel?

Personally I would build this frame out of H4 50 x 100 mm timber, you could have some purlins for the roof and some access doors on the front.

Do you have any photo's of the general area where this is going to be installed?, as that would be really helpful to visualise what you've currently got.

Also do you have a concrete pad poured under where the batteries will be installed?

Could you please get back to me with this information?

Thanks,

Mike T.

[Bluejay]

Thanks for the info on the metal screws. That's going to be useful. 

Regarding how far away the colorbond panels will be from the batteries, my understanding is that it needs to be a minimum of 200mm (see https://www.solarquotes.com.au/blog/solaredge-home-battery-review/ ) so it is up to me how deep the frame is - easy to have 300+ clearance from the batteries. I had wondered about radiant heat - maybe fixing some sarking to the inside of the frame members that have the colorbond attached on the outside would provide an insulated airspace.

[Bluejay]

Hi MikeTNZ

The wall is a rendered brick wall with concrete laid up to it. I will use metal for the frame mainly as I want to develop my welding skills after a recent tech course - though I appreciate many are more comfortable with wood.

thanks

[MikeTNZ]

Hi @Bluejay,

Nah, all good mate, what welding process will you be using, MIG or stick welding?

As a welder myself, this is a great skill to learn.

Best of luck, with your project, if you need any welding advice, by all means, let me know.

Cheers,

Mike T.

[Bluejay]

Hi @MikeTNZ 

Thx for the reply. I'll be using MIG- though given my very intermittent use, I'll use gasless flux-cored wire rather than the std gas. I've tried this combo with gal section and I've found it works well.