Solar mounting questions

[vantech2022]

Hi,

A few general questions if I can:

When doing a DIY solar install on a roof, does this impact home insurance? Appreciate they need to be told, but do they require MCS certificates? I am an electrician, so competent enough to do these works, but I do not have an MCS registration.

What is the minimum distance to the edge of the roof? I read 300mm and 200mm in different places?

Thanks all.

[Oldgreybeard]

Interesting question. I'm not sure that there is any impact on insurance with regard to MCS or not, as frankly MCS certification isn't a measure of quality or workmanship, and it's just as likely that an MCS person might do something that causes damage as a non-MCS person. Also, the roofing industry in general has been beset with cowboys doing poor work for years, yet insurers don't seem to take issue with it.

When it comes to mounting distances it depends on the roof type, pitch and installation method. Our panels are right down to the gutters, for example, as I used in-roof mounts, so the panels are the roof covering for a large part of the roof. The minimum distance with other mounting systems depends on several factors, not least being the type of roof covering. There's usually a need for on-roof mounted panels to be spaced a short distance from the eaves edge to allow rain water to flow down on to the roof covering and then into the gutters, without the risk of overshoot, where in heavy rain water might shoot over the top of the gutters. Steeper pitch roofs generally need the panels to be further away from the eaves edge than shallower pitched roofs.

For on-roof mounting systems the spacing at the sides can be pretty tight with little risk of problems. Same at the ridge, no reason not to run panels pretty close to the ridge, with the proviso that they shouldn't be fitted so that there is a risk of wind getting under the top edge, particularly in exposed locations.

For in-roof systems the minimum side edge and top spacing is set by the available flashing kit width. The flashing needs to run under at least half the width of the tile of slate roofing usually, so in practical terms that means leaving a tile or slate width margin at the sides.

[vantech2022]

Interesting question. I'm not sure that there is any impact on insurance with regard to MCS or not, as frankly MCS certification isn't a measure of quality or workmanship, and it's just as likely that an MCS person might do something that causes damage as a non-MCS person. Also, the roofing industry in general has been beset with cowboys doing poor work for years, yet insurers don't seem to take issue with it.

When it comes to mounting distances it depends on the roof type, pitch and installation method. Our panels are right down to the gutters, for example, as I used in-roof mounts, so the panels are the roof covering for a large part of the roof. The minimum distance with other mounting systems depends on several factors, not least being the type of roof covering. There's usually a need for on-roof mounted panels to be spaced a short distance from the eaves edge to allow rain water to flow down on to the roof covering and then into the gutters, without the risk of overshoot, where in heavy rain water might shoot over the top of the gutters. Steeper pitch roofs generally need the panels to be further away from the eaves edge than shallower pitched roofs.

For on-roof mounting systems the spacing at the sides can be pretty tight with little risk of problems. Same at the ridge, no reason not to run panels pretty close to the ridge, with the proviso that they shouldn't be fitted so that there is a risk of wind getting under the top edge, particularly in exposed locations.

For in-roof systems the minimum side edge and top spacing is set by the available flashing kit width. The flashing needs to run under at least half the width of the tile of slate roofing usually, so in practical terms that means leaving a tile or slate width margin at the sides.

Thanks, great input. I think I will allow 200mm or there about around the edges.

Can you confirm what you did with electrical sign off up to the solar inverter? Part P or building control notification (or nothing)?

Thanks.

[Andy]

Part of the Mcs now is having proof that the roof can take the loading. Ie a structural report. This is both for the static load and the uplift generated. So, I'm not sure where you would stand if something did happen to the roof.

I read somewhere that the standard distance from the edge is 30cm. My barn turned out to fail if the panels were right to edge. Slipped back a bit they were fine.

[Mr Gus]

Snow / wind lading has been a part of things for years (thankfully)

Your house plans should give some insight as to design & load capabilities, & take it from there.
Must admit I see very few "to the edge" roof installs.

Are the roof tiles anything special or simply bog standard hefty concrete type?
Really would recommend you dig out a solar install manual first & foremost, plenty of manufacturers so plenty of physical pages of material with lots of example & much legwork done.

End of a building is a blast zone for air turbulence in the 1 in 50 year storms roofs are engineered for, stepping away from the edge is somewhat of a storm load spreader rather than transferring everything across & through everything (the way I figure it) kind of like a weir as it can be to slow water force downstream. (Downstream being the rest of your roof)

[vantech2022]

Snow / wind lading has been a part of things for years (thankfully)

Your house plans should give some insight as to design & load capabilities, & take it from there.
Must admit I see very few "to the edge" roof installs.

Are the roof tiles anything special or simply bog standard hefty concrete type?
Really would recommend you dig out a solar install manual first & foremost, plenty of manufacturers so plenty of physical pages of material with lots of example & much legwork done.

End of a building is a blast zone for air turbulence in the 1 in 50 year storms roofs are engineered for, stepping away from the edge is somewhat of a storm load spreader rather than transferring everything across & through everything (the way I figure it) kind of like a weir as it can be to slow water force downstream. (Downstream being the rest of your roof)

The house is brand new, and the tiles are standard concrete tile. I don’t think loading will be an issue to be honest. I had 3 solar companies come out to quote who all agreed to do the works but then appeared to lose interest when it was apparently only 3 panels would fit, hence why I will do it myself.

I will move the panels in by 300mm on each side, which should I think negate issues with wind.

[vantech2022]

Part of the Mcs now is having proof that the roof can take the loading. Ie a structural report. This is both for the static load and the uplift generated. So, I'm not sure where you would stand if something did happen to the roof.

I read somewhere that the standard distance from the edge is 30cm. My barn turned out to fail if the panels were right to edge. Slipped back a bit they were fine.

Do the installers physically get this report from a structural engineer for each and every project (doubtful) or do they certify this themselves?

[Oldgreybeard]

Do the installers physically get this report from a structural engineer for each and every project (doubtful) or do they certify this themselves?

They just use a simplified method that doesn't involve any calculations, based on the region, roof pitch, and roof construction. There's no structural engineer involvement, or at least there wasn't when our panels were put in. I believe the method used is much the same as that used for other building regs requirements, where it is assumed that standard components are already designed to take certain live and dead loads, so there is no need for builders to have to do any calculations. This is how floors and roof trusses are built, no one usually bothers to do any calculations they just use span tables and pick the right standard components for the span and load.