Industrial Roof Fixing strategy

[confounded]

We have not had any commercial projects yet but I have been asked by a family member about the fixing strategy to a modern commercial roof because they are considering it.

The key thing is it is a big roof and the steels are 6m apart, what is the method for coping with this?

 

[SolarCity]

Vertical rails mounted to the purlins? Without seeing the roof, it's difficult to say.

 

[Worcester]

You really out to get a structural survey first before you even bother putting effort into the design, because that could easily skew the whole economics of the scheme.

The payback is very simple, it almost always works out the same give or take a few %.

If it's 'modern' they may well have access to the original builder / designer. (Their contact details will be on the drawings / plans and if they haven't got them, they may well still be available electronically from the local council's planning department)

 

[confounded]

Thank you for the replies. To cut a long story short my relative is out in New Zealand where he met up with his friend and builder/designer of the commercial building in the UK who emigrated to NZ. The designer was curious how you would install panels on the roof and I was asked what the method would be used so my relative could relay this to the designer. I am not familiar with large scale systems and thought it was a good opportunity to seek advice on here.

It sounds like the advice should be coming from the designer, so the next question is what do they need to provide to the existing roof to allow the system to be installed, baring in mind the distance between steels is 6m?

 

[Worcester]

@confounded

Amongst other things I am a qualified Civil and Structural Engineer, and even I can't answer your question without a site visit....

 

[confounded]

@confounded

Amongst other things I am a qualified Civil and Structural Engineer, and even I can't answer your question without a site visit....

I am not looking for specifics just looking for a general overview of how you can mount a system with such wide spacing of possible fixing points. As seen from the link below it looks like there are different strategies to the normal domestic system where a fixing is every 800mm for example.

United-Kingdom (1.16MW) A-SUNENERGY.COM

 

[SRE]

depending on the roof type, the garantee may be viod if you drill through insulated roof panels into the z rails, it can bone with renusol or scletter kits have a look at there websites, it will give you a better idea of what you are looking for, our structural engineer told us that he would not have any problems with any steel structural building having pv installed, but make sure you make sure you look at the wind load for that area. You may need to install extra purlins to cater for the fixings. the biggest problem you may have is the length of D/C cable to the isolators, try to get the invertor central to where your pnls will be installed. hope this helps.

 

[Worcester]

Look closely at that roof and you'll see that they have a support / purlin structure every 1.2m under the roof.

(Panels are 800 wide, 15 panels = 12m, look closely at the transparet ones and yiu can see a mid support, plus there will be a support at each panel lap, 5 panels = 10 supports + eaves, covering 12 m = 1.2m)

As an engineer, unless it has a structural roof covering it isn't going to support it, they will need to put some intermediate supports in, typically aluminium rails need to be anchored for two reasons.
Load - bending, deflection
Uplift from wind, it needs to be securley anchored to the substructure. You could easily have mountings just ripped out from the substructure.
As such you'll need something custom if you want to span more than 1.2 - 1.5 meters.

So your solution would have to be a custom substructure support system of some kind, and then you can put any of the popular flat roof systems over the top. - Schletter has some great products for industrial roofs - go take a look at their site. Schletter GmbH | Home

Once again - you NEED to get a Structural Engineer to look at it , and that should be your advice. -

"There are loads of mounting systems that can do it, however before we can say wether it can or can't be done, you'll need to get a structural engineer to check it out"

 

[confounded]

Guys, thank you for your replies, very useful!