Solar panel fixing

[Libby2017]

Hi, I,m looking to fit solar panels on my Burstner Delphin 680 (2006 model). Any suggestions as to the best adhesive to use to fix the plastic corner supports to the roof with? Also will this be sufficient or should an additional method be used as well?

Thanks

[Mickt]

I have used Sika Flex 522 I  the past ,clean fixings and roof and rough up with glass paper.Dont push panel down to hard ,leave a bead of Sika

[Libby2017]

Hi Mickt

Thanks for this. I've seen Sika Flex 522 suggested elsewhere. I'll give it a go.

[Globebuster1]

I'm not a fan of the plastic supports, I think they are crap - but if you are using them make sure you rough them up and give them a good clean with Isopropanol or MEK, ensure the roof is also clean.

There are many different PU/Hybrid sealants available - Sika, CT1, Puraflex, 3M and the like [Don't use Plumbers Mait 😁😁😁] all will do a reasonable job.

Ideally you would use a primer with Sika products, although with 522 this is less critical - and most seem not to bother or are unaware.

As was suggested by Mickt, you need to have around 3/4mm thickness of sealant between bracket and roof substrate - tile spacers are useful.

If you are not adding a mechanical fixing, let the sealant ooze through the bracket fixing holes - this is one occasion where an untidy finish is actually beneficial! - and you won't be seeing it anyway.

[Derek Uzzell]

If a SIKA product were to be used, the logical choice would be Sikaflex 554

https://sunworks.co.uk/product/solar-panel-adhesive-sikaflex/

(Not sure if SIKA actually markets 554 in the UK, though...)

[Globebuster1]

Sealants have almost become too complex  - although it appears that some manufacturers are making 'Joe Bloggs' friendly products now, that require less prep and knowledge.

Me, I'd be happy with either Sika 291-i - or if you're worried about sheering strength 292-i

Then again CT1 is pretty good, as are Bostik Simson products.

The biggest problem with using 'plastic' mounts [apart from UV degrading] is understanding that prep is important, and that some of the very best sealants will not adhere so well as some of the cheaper alternatives.

[Brian Kirby]

On 08/08/2023 at 15:22, Libby2017 said:

Hi, I,m looking to fit solar panels on my Burstner Delphin 680 (2006 model). Any suggestions as to the best adhesive to use to fix the plastic corner supports to the roof with? Also will this be sufficient or should an additional method be used as well?

Thanks

I think it is fair to say that all adhesives exposed to UV light degrade over time.  How quickly this will happen in a particular, "real-life", case is an unknown.

The initial strength of the fixing will depend upon the materials used by Burstner for your Delphin's roof, by how they have weathered since 2006, on the materials used by manufacturer of the solar panel's corner supports, on the standard of preparation of both for the adhesive, on the quality control achieved while mounting the panel on the Delphin roof, and on the compatibility of the adhesive with the other materials.  Again, I would regard this combination of variables in the process of bedding the panel mounts onto the Delphin roof render the remaining strength of the joints at any future point in time a further unknown.

The critical risk is the consequence of the panel breaking free from the roof while driving, where that might happen, and the potential impact on following traffic should the electric connecting cable fail to adequately tether the panel to the van until you become aware that it has broken free and can stop the van.

So, to answer the second part of your question, it depends on your perception of the risks implicit in using adhesive alone to secure the panel in place.

In view of these variables and uncertainties, I would say the fail-safe option has to be to use sufficient mechanical fixings in addition to adhesive, relegating the adhesive primarily to maintaining an effective water seal around the mechanical fixings, and secondly to reinforcing the mechanical fixings (i.e. belt and braces! 🙂), with the primary objective of ensuring that the panel cannot fly free form the Delphin roof - with who knows what consequences for following traffic.

That you asked the question suggests that you also doubt the long-term reliability of adhesive alone for this task.  As you will have gathered, I think your doubts are wise and well-founded!  🙂