TedM

Have you taken I to account the extra 100kg of panels plus the ballast for each one? How much ballast do they take... I guessed at 100kg each 🤷🏻‍♂️ My numbers were for a standard roof plus about 700kg extra.

If I was doing this I'd fit a plate to the wall and then new bigger joists onto joist hangers screwed to the wall plate, like this: You won't be able to get the new joist right next to the existing one but I'm not sure that matters - you could fit them at the mid point between the existing joists. I would probably use an acrow to apply a little bit of upward pressure to the new joist while fitting the hanger - this is to make sure the new joist is doing some of the work. It seems that 8x2 (47mm x 195mm) C24 graded timber would be a starting point - but this is also assuming the walls are up to taking the extra weight.

Oh! ......Didn't know.

You would basically need to strengthen each existing joist - two options might be: bolt a steel strap to one side of each joist (we've done that before to a pair of roof purlins with the blessing of our SE) add new joists of the correct diameter - but they will def be deeper which would then affect the ceiling height of the room below. There may be other options but I would imaging they would all involve considerable intrusion into the room below ceiling and it's associated repair costs.

My late dad was an architect and always said to never put anything through a flat roof unless there was absolutely no other choice. 5 panels would probably mean 20 holes, meaning that it would potentially be 20 x more likely to leak at some time in the future 😬

Hmmm. A quick look at good old AI suggests: According to standard UK span tables (BS 5268), a 2" x 4" (specifically 47 x 100 mm) joist typically has a maximum allowable span of only 1.7 to 2.1 meters depending on the wood grade and spacing. At a 2.4m span, the joists are "undersized" and prone to significant sagging or structural failure under standard loads. So maybe no planning required but some acro props probably will be as whatever you put up there may well try to find its way downstairs fairly quickly 😬 (The 70's has a lot to answer for!) "I'm sure it would payback within a couple of years or so as I can fit myself." Possibly a bit longer if you take roof repairs into account 😉

Even better - barcode on the hardware that you scan with your phone, add your name and address and press send. It creates the certificate for you and sends the notification to the correct DNO and puts the info in a national database 👍🏻 (I create mobile apps as my business and that would literally take 15 minutes to create!)

I wonder how they're going to deal with G98 and G99. Are they going to exempt anything less than 1kW from G98? Otherwise there's going to be a big pile of applications to be dealt with! And then there are people with an existing G98 installation who want a bit more - are they going to have to submit (and pay for) a G99 application?

A number of reasons I guess - but it seems the prices have already gone up since last week. The panels I bought from Plumbnation at £82/each are now £92 at CityPlumbing!

It can be cheap at the moment (depends on your tariff) but who's to say what will happen in 12 months time. One potential outcome is that as the number of EVs on the road increases so does the number of people using the spare overnight generation - so prices go up.

No, but it's only 800w so probably close to 100% self-use.

Got to be good news! I see a big demand coming from people wanting an outside socket fitting! I've got a place by the beach that already has a small (3kWp) south facing array on the roof and I was thinking of adding a couple of panels facing west to get the afternoon/evening sun - this might be just the job!

I was wondering about that and, as I am a fantastic procrastinator, I've gone and bought 5 x DMEGC All Black 515W Bifacial panels from PlumbNation as City Plumbing are out of stock of what id like and can afford. The only downside I can see is that delivery takes 8 days ☹️ But I guess that gives me some time to run the cables as they need to go in/under the concrete yard base.

Ahhh, OK so DMEGC should be OK. Are >500w [bifacial] panels actually better than 460w panels or are they just fudging the numbers from some potential generation from the rear? In other words, spend slightly more on bifacial 500w panels or less on 460w panels?

I'm looking at two different panels - both 500w and both about £80/panel with free delivery. Is there likely to me any real difference between them? (One is the LONGi Hi-MO X6 and isn't in stock, the other is a DMEGC and is in stock)

Frame starting to go up. Two diagonals and horizontals (ledgers) still to be fitted which the panels will clamp to. I'll need to alter a few bits after they've gone but it's much easier and quicker than doing it myself! 😁

I'm still undecided as to how to clamp the panels 😩 Either use the eBay clamps and just fit them directly to scaffold tube, or save a little money and somehow fit mounting rail to the scaffold tubes and use 'real' clamps to hold the panels. Realistically there's probably no difference in price by the time I've bought something to fit the mounting rail to the scaffold tubes.

I'm going to try and copy that if you don't mind! Looks like it should give good access to the back of the panels - there's a wall at the back of mine but I want to get in a keep under the panels fairly clear. I'm not looking to export anything! There's an Immersun that heats a 250L Megaflo after which spare power will go into the electric unfloor heating in the kitchen which takes 2kW when it's heating. I also have electric underfloor in the bathroom plus a few electric heaters around the house all of which are controlled by Shelly relays. I have a number of Shelly Actions set that will switch various devices on and off depending upon how much power is being exported - such as this one: I've also got another E/W facing array that gets the original FIT payment (for every kWh it generates) I'm not bothered about exporting anything really. [The new array is completely separate to the existing one]

That looks good 👍 A little update on mine..... my mate is sending a team over next week to build it for me!! I'm obviously not trustworthy 😬

I have literally no idea why I drew the ground mount like that..... so many uprights!! 🤦‍♂️ This is how it's actually going to look with just 6 uprights - 2m between each set should be fine, but I can always ask my mate who owns a large scaffolding co (hence the free poles 😉)

Something along these lines. Front will be around 500mm high and the back will be around 2000mm high (whatever to give 45-50 deg angle). There will be two diagonals on the rear uprights for bracing.

I'm actually swinging back towards all scaffold pole construction using those ebay clamps (price comes down when you buy 12) as it will handle overhangs better and the poles are free. I'll see about doing a sketch.

Stupid questions probably but how much gap do I need between panels? I'm going for 5 panels at 1134mm wide each. Can I get away with 2 x 3m unistrut for each horizontal run? (scaffolding poles being delivered today)

Cost: The tubes are indeed free! Ease of cutting: I've just purchased a 'vintage'* Record pipe cutter for almost no money which means I don't need to use the demon angle grinder 👍 Connecting poles: There's a pretty huge selection of scaffolding tube connectors for about £1.50 each Mounting panels: see my link above - although £8/clamp is pretty spicy! AI suggests I make the frame from the scaffolding tubes and then fit unistrut to the frame to mount the panels - so what Unistrut do I need for 5 panels? * How can a tool be 'vintage' when you can still buy new ones! 🤨

I was thinking about using these to clamp the panels to the poles: https://www.ebay.co.uk/itm/376886172656?_trkparms=amclksrc%3DITM%26aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D20240627101223%26meid%3D5cf7769367854ef8b06318011d31e8fa%26pid%3D102236%26rk%3D1%26rkt%3D1%26sd%3D376638412709%26itm%3D376886172656%26pmt%3D1%26noa%3D1%26pg%3D4481478%26algv%3DDefaultOrganicWebV9BertRefreshRankerWithCassiniEmbRecall%26brand%3DUnbranded&_trksid=p4481478.c102236.m5337