Solar panels - portrait vs landscape orientation

roadweary

A new curveball….I've had at least 3 companies quote for panels in landscape in such a manner that there's probably around a 145mm gap between the roof ridge line and the gutter line.

I've just had a conversation with DCL Renewables who were very cautious about such an install on the basis that it would breach the panel warranty!

Just when I thought I had the right design, panels and components and was just selecting the right installer.

NedS

https://forums.moneysavingexpert.com/discussion/comment/82037138#Comment_82037138

MCS guidelines recommend 400mm gaps around edges on pitched roofs, although these can be reduced where there are other mitigations in place to combat wind effects. For example, is it a low roof that is sheltered from the wind? Have extra fixings been used and has the roof been structurally reinforced to sustain the increased load caused by placing panels closer to the edge?

At the ridge, the panels must not protrude above the line of the ridge, so the minimum gap will also be determined by the height of the fixings.

MCS also state that any equipment should be installed to the manufacturers guidelines, so you would also need to consult the OEMs recommendations and adhere to those.

roadweary

https://forums.moneysavingexpert.com/discussion/comment/82037285#Comment_82037285

Hi, thanks for this. We're definitely not sheltered. Have I understood correctly that potentially at the ridge line the 145mm gap wold be sufficient so long as the panels don't protrude above the ridge?

Towards the gutter, is using additional fixings sufficient if the gap is only 145mm?

Would all of that detail be captured in a standard design report for the system that an installer would provide? Else how would the panel manufacturer by able to check or refute the installation details?

The panels would still be exposed to extra wind stress I guess closer to the edge off the roof, so would those mitigations cover everything?

I was hoping that if the company is MCS and RECC certified that they'd have to adhere to those standards and check the roof structure etc?

If that is the case, if a panel were to fail, if the panel manufacturer said the warranty were voided due to the installation, would the installer not be liable?

I was hoping that those certifications would ensure what ever was installed would be fully covered for workmanship, and that the manufacturer warranties would all apply. Now I'm just not sure.

QrizB

If that is the case, if a panel were to fail, if the panel manufacturer said the warranty were voided due to the installation, would the installer not be liable?

What warranty is the installer themselves providing?

Eg. if the installer is providing a 25-year warranty on materials and workmanship, backed by insurance via eg. HIES, the panel manufacturer's own warranty is moot.

If however the installer is only offering a 5-year insurance-backed warranty, with claims after that date relying on the manufacturers, it becomes more important to adhere to those warranty terms.

NedS

Panels cannot protrude above the height of the ridge as this violates permitted development rights, so would not have planning consent. So this is non-negotiable. This is a height thing, not a distance from ridge thing. The higher the mounting is off the surface of the roof, the more distance from the ridge will be required, and the pitch of the roof will also factor in to this with a shallower pitch requiring a larger distance to keep the height below the line of the ridge. The further down the roof you have to bring the panels to achieve this, the less space you have at the bottom of the roof to the gutter. This is also just common sense. If the panels protrude above the height of the ridge line, the prevailing wind will catch the protruding panel and rip it free.

The 400mm MCS recommendation is a guideline, but it's not unreasonable and is there for good reason. It can be reduced where mitigating action is taken. If you were talking about reducing to 300mm gaps, that may be reasonable, but 145mm is a significant reduction (to around a third) in the recommended gap and not something I would be comfortable with, especially in a non-sheltered location.

As @QrizB discusses, the manufactures recommendations are just that and are important if you are relying on their warranty. But again, if you do not adhere to the manufactures recommendations, you should not be surprised if the product fails (ripped off in high winds).

I would be having a detailed discussion with the installers as to why they feel the MCS 400mm recommendation does not apply in your case and what mitigations they are planning to take in order to feel able to significantly reduce these recommendations, and what type of warranty backup are they prepared to offer.

I also would not touch any company who have not been trading for at least 10 years under the same ownership (you can easily check on Companies House website)

roadweary

Hi, this is my current design, can you please let me know what you think? Let's not go into why I've had to come up with this….

The diagram is not to scale. Roof is at least 4.6m wide, usable vertical length at least 6.04m. Pitch is 45 degrees.

The panels are 1.954m by 1.13m. So 3 rows in landscape take up a vertical height of no more than 3.45m. The row portrait panels is 1.95m so no more than 5.4m in height. That leaves 64cm or more to be split between the gutter and ridge margins. Does that work?

The maximum width used is 3.45 metres on the 4.6 metre width.

Thanks!

PS on the South (unshaded side) there is a light tunnel, hence one panel missing.

NedS

640mm split (320mm each) sounds a lot better than your previous 145mm.

What I would say is that if you are interested in maxing out the potential of your roof (as you should be), any really good solar installer should be working with you by doing a full survey and coming up with different configurations to maximise the potential. Maybe they can use bigger or smaller panels to maximise the available space. I know far to many installers will say we supply these panels and that's it, because they've bought a container full from China so aren't prepared to go source other panels that may be a better fit for your roof. This probably helps keep the price down, and is great if their preferred panels are a perfect fit for your roof.

If they are not prepared to do this work, maybe you can research some common panel sizes and see if you can come up with some better configurations. I now in the 12 months between having our first and second arrays installed, the panel sizes changed and this came as a bit of a surprise to me, although the new slightly larger panels still fitted on our roof without issue.

roadweary

Hi,

Yeah, I agree and get it. I work in presales for a software company, and what I'm seeing is that in solar the sale guys pretty much fly solo and take the occasional question to their presales (engineers / installers).

I get a similar mess when the sales guys get to far into conversations before consulting me.

I've pretty much settled on DCL Renewables for the moment. They've had the right balance of being responsive to my plethora of OCD emails (the other front runner takes 1 - 3 days to respond to emails and sometimes forgets and calls me to catch up), and won brownie points for questioning the config (panels vs regs) a different installer gave that the others accepted without question.

Another installer agreed to the same config after a physical survey. They did a drone survey and measurement in the loft and I swear the guy decided there was safely 6.1m which still feel too little for the 5.75 vertical array of 5 landscape panels.

Whether luck or otherwise, DCL questioned it, and in the meantime I proposed this config.

Potentially my roof might have as much as 6.36m which probably would allow the 5 landscape rows.

The quote I feel is good, particular because they are providing the higher powered gen 3 Aiko panels.

They don't do a survey till after they take the 10% deposit, but they do lodge it with HIES and it's fully refundable even if I just change my mind.

They've been around since 2013, 4.6 on TrustPilot, only 16 reviews. TrustMark, RECC, MCS and all the other things. The quote is very good, but please do challenge me

Martyn1981

The quote I feel is good, particular because they are providing the higher powered gen 3 Aiko panels.

Just to say, I also think that's a good quote, and whilst it's only a smidge more, you may find that 540Wp model panels are now available. Same dimensions.

Every little helps.