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How to span a gap between structures?

I am looking to span a gap between two steel structures - about 500mm apart.

Both structures are made of steel.

A short-stay with corrugated cladding to steel frame and a patio with trim deck to steel

frame.

im wanting to bridge the gap between the two with clear polycarbonate sheets for rain protection.

I have lengths of leftover light steel purlins and battens which Im planning to attach to the roof of each structure and then attach polycarbonate. There's enough fall for water to flow onto the patio roofing.

Question - would the new cover be light enough to screw the battens lengths to the steel roof sheeting - or should I screw thru to the purlin or rafter underneath?

advice greatly appreciated

Sean

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Accepted answers

JacobZ

Hi @SeanWA,

A warm welcome to the Bunnings Workshop community and thank you for your question.

I would suggest that any additional framing is attached to the framing, not the sheets, as this will ensure the forces applied to the new polycarbonate roofing are transferred into the structures, which will then transfer it down into the foundation.

The weight of the sheet is not the main concern, it is the ability for it to resist wind loads. If wind whips up underneath a roof, it can peel the roof sheets off the frame. If you were to attach the new sheets directly to the old sheets, then you would risk this peeling action on both sheets.

It is also worth noting that by tying these two structures together, you are introducing new wind loads that they were not originally designed for, so it is likely worth consulting an engineer to ensure you are not taking these structures outside of allowable limits for wind loads.

If you wanted to avoid this, constructing a flyover roof, where the two structures are not actually attached to each other is likely a better option.

Allow me to tag @Nailbag for his thoughts.

Let me know what you think.

Jacob

All comments

JacobZ

Hi @SeanWA,

A warm welcome to the Bunnings Workshop community and thank you for your question.

If you wanted to avoid this, constructing a flyover roof, where the two structures are not actually attached to each other is likely a better option.

Allow me to tag @Nailbag for his thoughts.

Let me know what you think.

Jacob

SeanWA

Thanks Jacob

i thought as much

I will give my builder a call back and see what can be done

Cheers for reply

Sean

Nailbag

Hi @SeanWA

I would install a custom fabricated steel frame tied to the left hand roof counter-levered across to but not connected to the right structure just under its guttering. To @JacobZ point these structures should not be connected due to independent movement. Downpipe/s from the right structure guttering to the counter levered roof if required to assist with water run off.

Nailbag

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