One of the biggest downsides of installing solar panels on a rooftop is that maintenance of the actual roof structure becomes much more difficult with solar panels in the way. But for many people who don’t have huge tracts of land, a roof is wasted space where something useful could otherwise go. [Mihai] had the idea of simply eliminating traditional roofing materials altogether and made half of this roof out of solar panels directly, with the other half being put to use as a garden.
Normally solar panels are installed on top of a roof, whether it’s metal or asphalt shingles or some other material, allowing the roof to perform its normal job of keeping weather out of the house while the solar panels can focus on energy generation. In this roof [Mihai] skips this step, having the solar panels pull double duty as roof material and energy generation. In a way this simplifies things; there’s less to maintain and presumably any problems with the roof can be solved by swapping out panels. But we would also presume that waterproofing it might be marginally more difficult.
On the antisolar side of the roof, however, [Mihai] foregoes the solar panels in favor of a system that can hold soil for small garden plants. Putting solar panels on this side of the roof wouldn’t generate as much energy but the area can still be useful as a garden. Of course we’d advise caution when working on a garden at height, but at least for the solar panels you can save some trips up a ladder for maintenance by using something like this robotic solar panel scrubber.
Story is useless without picture of room ceiling below panels.
How waterproof is this setup?
Closeup of how he flashed the panel joins?
I’d overlap and overlay them a half inch, like large fragile tiles.
AmateurRooferaDay?
Presumably you would put insulation on the inside, which in most cases is aluminum (painted or not – you could always paint it). In some setups you run cooling (hybrids) to cool the panels and save excess heat for later (useful during the night).
It’s not a novel thing, ppl are putting panels on walls as well, wrapping the entire building. It’s an emerging trend in PVT. You can save a lot on construction costs if you can skip the outer part of the walls.
That was my plan too: to reduce the cost of the building by removing one layer (the tiles)
I plan to remove the heat with some cooler at the top of the roof.
Also I assume no air conditioning or heating, because if there were then the energy generated by the solar panels would be quickly squandered by lack of good insulation. This seems like more of a Gilligan’s Island type situation, though, so maybe some pots and pans catching drips and no HVAC is the order of the day..
Air conditioning is moot because the “building” is open to the air. One wall is entirely missing.
The building and roof are still under construction. The roof is still open on one side.
What? Please do some numbers on that.
Heatpumps for heating are totally a thing (aircons are heatpunps, just running the other way). PV can cover much of the electricity for this (until you get heavy snow fall, and it’s covered under a foot of snow, or if you live in e.g. Tromso and it’s dark for three months). Solar heating works as well. My parents had that in their last home. Very low energy bills.
So please stop spouting FUD.
Did they change their comment or something, because none of what you said at all conflicts with their claim that an uninsulated roof made only of a single layer of solar panels would mean that the extra energy used by heating and cooling would exceed that generated by the panels, which is probably true, albeit incomplete because there’s no rule that says you can’t put insulation under solar panels
There is no problem with heating of cooling the house, because it is half buried in the ground! So, during summer is quite cool and during winter is quite warm.
I assume this is an unconditioned attic, so the floor of the attic is the only part insulated… No need to insulate the panels or grass sides.
What about this idea requires a lack of good insulation?
The house is half-buried in the ground which provides a good insulation.
Who insulates their roof? In most conventional construction, the roof is uninsulated in favor of batt or blown insulation laying on top of the ceiling joists. Same concept would apply here.
People with finished attics.
Have you considered following the links the article gave? A bunch of pictures are on the github page…
https://github.com/f-roof/.github/tree/main/pictures
As for the waterproofing, thought was put into it, but it doesn’t look very robust.
Yeah I expect that kinda response on MSN, but come on man, follow the provided links! You giving us a bad rep
GTF out FL follower!
We don’t like your kind.
Reading articles, following links…
Here is a new movie during a heavy rain:
https://www.youtube.com/watch?v=0JjJXp-amts
As you can see, there is no water inside.
How about under the solar panels.
That’s the terracing.
Which isn’t leaking, yet.
How much slope on the flat part of the plant terraces?
Going to want at least a bubble, assuming it freezes at some time during the year.
I would also want some overhang on the ends and bottom.
It’s often windy along with rain here.
Also: how much aluminum in that roof?
Roughly (e.g. ‘roof is aluminum sheet folded down terrace steps’ or ‘just flashing’).
Thanks.
With regular domestic scale panels you’d not want to overlap them – way too thick a frame around them, which is likely to cause heaps of trouble, and in many cases the active area is really close to the edge – shading that area is a bad idea for efficient solar generation. But if you could source just the silicon and glass stack or ones with a better mounting frame for the purpose I can’t see a problem with the concept.
Though I don’t really see the need to worry about the watershedding of the panels alone – just put them ontop of a membrane and the small cracks around each panel that can let water in just don’t really matter, or if you have the money to make a new product create a zinc roof style crimping ready solar panel production line or something similar.
The real issue is solar panels get really really hot if you don’t have lots of airflow around them, and don’t work very well at those elevated temperatures. So using them as the waterproof outer surface and the ceiling below in a traditional building at the same time would be a challenging task – think you’d need to actively watercool them (which is a PV panel type you can just buy). Can then use the heat for something useful too. That would I suggest end up being about equivalent to the normal uninsulated roof tiles and loft space most building have – going to get really toasty inside still on the sunny day, and cold over night as insulation value is terrible (though the waters thermal mass will even that out a fair bit).
Yes, lack of airflow under the panels would make for heat issues (and panels are less efficient at power generation at high temps, aside from transmitting heat into the structure).
My plan is to remove the heat through some pipes and coolers placed at the top of the roof. A cooler does not consume too much energy … and is needed only during the full summer-time when there is enough energy production.
Consider a resovoir , you can use it as heat storage for night and cooler weather, and the only complication is how large it should be, which can be scaled down by the efficiency of your cooler arrangement.
@S.O. What kind of reservoir? With water? How to I move heat from panels/air to water? By using pipes? It seems complicated …
There is “proper” tray solar and that works the same way. It’s now the normal way solar is put into new roofs in the UK and also when solar is added during a re-roofing of an older property as it’s usually cheaper.
There are some distinct disadvantages though – having solar as your roof reduces the amount of cooling on the panels a lot (not a big deal most of the year here), and also stops them acting as parasols keeping the worst of the suns heat off the true roof and the rooms below. So “on roof” solar still outperforms it somewhat but costs a lot more.
My house is half-buried in the ground, so during summer is cold inside and during winter is not very cold. Also, I plan to remove the excess heat using some vents at the top of the roof.
I have used bituminous tape for the garden part and silicon for the solar panels part.
Pictures with inside the roof are here:
https://github.com/f-roof/.github/blob/main/pictures/IMG_3316.JPG
https://github.com/f-roof/.github/blob/main/pictures/IMG_3355.JPEG
Also, more details can be seen in the movie that is posted in blog post.
A new movie during a heavy rain is here:
https://www.youtube.com/watch?v=0JjJXp-amts
As you can see there is no water inside the roof, even if there is a heavy rain outside.
That doesn’t look like anywhere that a building inspector is required.
Also, with a high wind some neighbor will be cleaning up broken solar panels from their garden.
You mean more than usual installation ?
The solar panels are well connected inside the roof.
Here is a picture:
https://github.com/f-roof/.github/blob/main/pictures/IMG_3358.JPEG
Also, I tried to remove one of them because initially I have incorrectly applied silicon, but I simply could not remove it!
Replacing a broken solar panel from roof could be a serious problem! I currently do not know how I’ll handle that situation if arrises!
The link contains a video where you can see some of the info you want.
To summarize: the “building” is open to the air. I think it was made specifically as a solar array first, and perhaps a toolshed second. It is not waterproof.
Yes, I built the solar part first (in 2024) and in 2025 I built the garden.
I would love to get a structural engineer’s take on this. I stopped being able to take this project seriously when I read “Wood should not be utilized for construction purposes. Trees are more important than for building houses!” He specifies it uses “tubes” and that it’s mostly made of “metal” but never actually specifies which type of metal. It’s probably steel but there are many different variants of steel with different properties. When you are building something, it matters which type of steel you use.
There is a good chance this is a deathtrap in the making.
“Trees are more important than for building houses!”
Most wood today comes from “lumber farms,” which are managed forests where trees are harvested after relatively short growth periods. We aren’t building homes from old growth timber and haven’t been for a very long time.
Where does wood come from?
– from trees.
Where does steel come from?
– from China.
;-)
I live in Romania. Our steel comes from a local manufacturer.
In the past 2 years, the temperatures rose significantly into our country (with at least 5 degrees Celsius during peak summer). We were very lucky that we had a lot of trees inside our yard and garden, which really helped us to survive to such temperatures. I prefer to keep trees alive no matter what!
Our tree comes from the nearby forest, which is abused! I stay away from using trees, because in the last 2 years it was very hot during the summer and only trees from our yard have protected us.
Looks like theirs was steel tubing which is commonly used for carports. Truth be told, it’s stronger than CFS which is often used for framing houses. One of the terrible trade offs of steel is thermal bridging though. I could see this being something like with prepackaged roof panels like they do with structural SIP. Where the solar panels provide structural rigidity with a water proofing layer underneath. You’d need some type of air channel to dry it out though.
There is no need for a layer behind. Silicon between panels is enough!
I utilized S235JRG2 steel.
Nice to see panels as roofing being done. I have seen it offered commercially in the UK before, and a quick google search came up with this company https://www.bmigroup.com/uk/solar-range/ There are probably several integrating the panels into tile and slate roofing.
That is way to go, but you must be careful with isolation between panels. Initially I applied silicon in the wrong way and I had water leakage inside roof. Then I fixed the problem using a bituminous tape placed over the silicon!
My mind always boggles when reading about the roofing practices in other countries. Asphalt? Put a real roof on it, and it will last for a century. Easily. It’s not magic, the Romans had roof tiles already. Maintenance? Really? OK, we had to get somebody to close a hole where once a chimney of a gas (not gasoline for those who like to misunderstand me) powered water heater was. The roof is about 60 years old, and I’m pretty sure it will last another 60. The wooden structure is still going strong, and the tiles will outlast me.
Other than that: for an addition / shed it looks really cool! Our shed is in the shade, so it won’t really work, but I might raise a plattform on top as a “tree” fort and put PV on that roof. I need to bury a proper power line to the shed then (and look at the regulations for those), so far it runs off a 12V solar light.
Might I suggest you don’t bury just that armoured cable but a conduit (assuming suck things are legal in your area – can’t see why they wouldn’t be but logic in legal restrictions don’t always apply), we didn’t do that and I’ve regretted it many times since.
We got a social club here in the Netherlands and the previous cable was put into the ground, without conduit, around 1970. This area is flooded very often in the fall and winter and when I mean flooded, I mean flooded. Too much rainfall and the river grows and the entire area is flooded with a layer of water on it. So the cable is constantly being wet dry wet dry. It’s probably the worst condition you can put it in. We recently replaced it not because the cable was bad, but because we wanted more cables to spread the load over groups and the old one couldn’t provide that. The cable goes onto another property that provides us with electricity. We have huge parties with multiple stages and all sorts of equipment, from a whole bunch of refrigerators to large sound systems, deep fryers, etc. And that cable lived in the ground without a conduit for 55 years without a problem.
I know that most places in the US are very strict on what you can and cannot do. A American YouTuber I watch had to use metal (!!!) conduit inside his workshop and wasn’t allowed to install his own (also metal!) power outlets. It’s the weirdest thing to me. I rewired a large part of my house myself, installed a new breaker panel, build a new kitchen and did all the electrics, replaced all the gas lines myself, replaced my gas boiler, I even installed a diesel heater in my workshop. I don’t need to and would never inform the government.
The point of a conduit to me is 99.9% because its so much easier to fish say an Ethernet or phone cable down a conduit alongside the power, or even another power line if you need more juice – which in the USA with low amp and voltage on their breakers wouldn’t shock me at all considering I’m at the edge if not over limit of my 32A UK breaker should I use everything at the other end without consideration – The armoured cable being good for years isn’t my concern, its that its a real pain to dig everything up to add more cables later when your needs change, especially if its running under a real garden you will have to actively repair afterwards – digging up and backfilling a grassy meadow is easy enough, if still more work than just pulling a new run through the conduit..
I’m sure that the Netherlands has building codes intended to ensure safe construction and electrical wiring. You can get away with ignoring it and not getting construction permits. You’ll probably never be bothered by the government.
If the electrical wiring you installed goes up in flames, however, your insurance company will probably be really sticky about paying out. No permits for the installation of the diesel heater? No proof that a qualified electrician installed the wiring or the outlets? Tough. No insurance payout for you to replaced your house and goods. If someone dies in the resulting fire, then there could also be criminal charges brought.
Pretty much every country in Europe has building codes and standards, and the insurance companies use any excuse they can find to avoid paying out on a claim.
I live in Germany. When we built our house, I did a lot of the electrical work. I installed the wiring in each room and installed the outlets and lights.
The wiring was completed by a qualified electrician, who double checked my work (which was all OK.) Officially, he installed all of the wiring. I have the receipts to prove it. If there had ever been a problem with it, he’d have had questions to answer.
I purchased very good solar panels that have 25 years warranty for energy production. So, definitively the mechanical part will survive even more!
Also, I did NOT utilized asphalt. I do not know how this idea was connected to my roof.
bitumen and asphalt are the same.
ok, but I utilized (75mm wide) bituminous tape, which has 1mm thick layer of bitumen … and I did not placed it everywhere … only between 2 consecutive gutters.
Yeah, not how you waterproof or use non galvanized steel in exterior locations. I would estimate 3-7 years before the wood rots, collapses, and needs a complete rebuild.
I painted the steel with good paint … also all screws and nuts are from stainless steel.
Roofing materials are generally engineered for the purpose. So if you list the required properties of a roof would panels tick off the boxes?
Consider that Tesla did the r&d to make solar tiles that have the properties of roof tiles. You still need the rest of the roof even then.
Consider that tesla merely copied the efforts of Dow Chemical which unveiled their powerhouse solar shingle in 2009, going to market in 2011, five years before tesla announced theirs.