ᐅ Green flat roof and photovoltaic system

Raising the structure, installing the photovoltaic modules, and adding a bit of substrate around them—done.

I wouldn’t ask any questions and would just build it without the greenery. Who’s going to come by to check your flat roof with a ladder anyway?

Thank you all for the many responses! They have already helped me a lot.
I understand that the most reliable answer can only come from the building authority, but I still find it quite helpful to hear from anyone here who has experience with this.

Müllerin schrieb:
what’s the problem now?
Do an extensive green roof with sedum plants, it works under elevated modules too, there are varieties that can tolerate it.
Then you get both.

The problem is that the architect believes photovoltaic and green roofing are mutually exclusive. Before I go straight to the building authority based on my amateur Google research, which suggests otherwise, I just wanted to check if anyone here has dealt with this issue before.

bortel schrieb:
Elevate, install photovoltaic modules, add some substrate around, done...

I wouldn’t ask anyone and would just build it without the green roof. Who would come to check your flat roof with a ladder?

In fact, aerial images are analyzed here in the district. A neighbor was inspected on site as a result.

I actually don’t want to avoid the green roof regulation. I think a green roof is a great idea and would like to combine both. Based on the feedback here, I will pursue this further. Thank you all!

quisel schrieb:
The problem is that the architect thinks photovoltaic systems and green roofs are mutually exclusive.

Well, even with an extensive green roof, it’s definitely a good idea to check more frequently whether the vegetation is becoming too dense.

quisel schrieb:
In fact, aerial images are analyzed here in the district.

And then you see a photovoltaic system on your roof with the green roof surrounding it. But who looks underneath the photovoltaic panels?

guckuck2 schrieb:
Well, even with an extensive green roof, it’s definitely a good idea to check more frequently whether the vegetation is getting out of hand.

We are definitely keeping an eye on that as well. However, overall, I consider it less of an issue.

guckuck2 schrieb:
And then you see a photovoltaic system with the green roof around it. But who checks under the photovoltaic panels?

Like with my neighbor: representatives from the local council or building authority.

But in the end, it doesn’t really matter. I WANT to have both. It’s not like I’m trying to avoid maintaining the green roof. So I have no problem greening the areas beneath the photovoltaic panels. Whether anything will grow in the shade remains to be seen... 😀

rick2018 schrieb:

Then please check with the building authority / planning office. That way, you get a legal statement.

Cooling effect through greenery for the units above lol
They will also be raised...
Of course, you can green the roof and then install the photovoltaic system on top. You just have to remove the substrate for the supports. But it makes more sense to leave it out.

I would definitely submit it with the building application.

Why should the substrate for the supports be removed? And then install the photovoltaic mounting system directly on the drainage layer?

We have a green roof and a 9.9 kWp system on the roof. And I would always do it that way. Every flat roof specialist recommends greening because it provides additional protection for the roofing membranes.

@quisel: We installed the green roofs on our three flat roofs ourselves — main roof, “secondary roof,” and garage — it’s not rocket science.

Here is the construction on the main roof, 110 sqm (1184 sqft): root-resistant fleece 300 grams, 20 mm (0.8 inch) drainage layer with laminated fleece, then 8 cm (3 inches) of roof soil plus a 30 cm (12 inch) gravel edge.

On the “secondary roof” and garage, together 90 sqm (969 sqft): root-resistant fleece 300 grams, 9 mm (0.35 inch) drainage layer with laminated fleece, then 8 cm (3 inches) of roof soil plus a 30 cm (12 inch) gravel edge.

On the secondary roof, there is a 30 sqm (323 sqft) roof terrace, and the rest plus the garage are fully planted with sedum plants. On the main roof, only the area outside the photovoltaic system is greened.

Material costs were just under 4,000 EUR.

Where did you buy that? I want to add greenery here as well, but I’m having trouble finding anything under 40€/sqm (per square meter).