Mistral Posted April 13, 2019 Share Posted April 13, 2019 (edited) Wanting to mount panels on my flat car port roof - old style corrugated asbestos type. Presume these would not be mounted flat but upright at an angle. What best to use for mounting. Cost per panel? I guess aluminium as we are at the coast. The car port roof has a slight drop from right to left to allow for water run off. Faces North West. Edited April 13, 2019 by Mistral Quote Link to comment Share on other sites More sharing options...
Jaco De Jongh Posted April 13, 2019 Share Posted April 13, 2019 2 hours ago, Mistral said: What best to use for mounting. I cant say this is the best, but I recently started using this range of mounting equipment. Renusol_Katalog_catalog_2016_2017_160531.pdf Its cheaper than Unistrut and a lot lighter because its aluminium. Just as info, If you are interested in something like this, I can help doing a costing on it. I just need to know what your asbestos sheets are lying on and how many panels you want to mount as well as the angle you want to mount them at. Quote Link to comment Share on other sites More sharing options...
___ Posted April 13, 2019 Share Posted April 13, 2019 2 hours ago, Mistral said: Presume these would not be mounted flat but upright at an angle. Yup. You lose way too much by putting it flat. 43 minutes ago, Jaco de Jongh said: I cant say this is the best, but I recently started using this range of mounting equipment. Jaco supplied me with the hardware I needed for this. This is roughly what it looks like. It bolts together pretty much with a 5mm Allen key. Hanger bolts going through the roof into the wooden beams below. You're looking at around 3.5k for this. Quote Link to comment Share on other sites More sharing options...
Mistral Posted April 13, 2019 Author Share Posted April 13, 2019 Many thanks for the info. Still calculating number of panels I need. Quote Link to comment Share on other sites More sharing options...
Mistral Posted April 13, 2019 Author Share Posted April 13, 2019 3 Panels R3.5K? Quote Link to comment Share on other sites More sharing options...
___ Posted April 13, 2019 Share Posted April 13, 2019 3 hours ago, Mistral said: old style corrugated asbestos type. Now the only thing that concerns me is that asbestos roof thing. The first thing you have to find out is if it is asbestos, or Fibre-cement. If the roof was put up after 1985 chances are it's not asbestos. If it is asbestos, then the rule is generally that as long as you don't disturb it, you don't have to replace it immediately. Natural wear (wind and weather) causes smallbits of fibre to be dislodged and it washes down with the rains and is generally (according to the safety people that briefed us at a place I used to work) pretty harmless. But once you start removing roof sheets, you have to take care not to get the fibre into the air. So you pretty much cannot throw the sheet off the roof into the ground... it has to be carefully lowered and all that. Now you won't be removing sheets... but you are going to drill into it... and that to me seems like the kind of thing that you probably want to consult someone on. That is IF it is asbestos. Quite often it isn't, it just looks similar. 4 minutes ago, Mistral said: 3 Panels R3.5K? The rails are 4.2 meter, so I have space for 4 panels up there. I only put up 3 for now and decided to leave the rails in case I ever change my mind. The beams below are spaced 1.2 meter apart, so that dictated how many triangles I had to put up. That is pretty much the maximum spacing I would advise in any case. Quote Link to comment Share on other sites More sharing options...
Mistral Posted April 13, 2019 Author Share Posted April 13, 2019 (edited) House was built in about 1978 but carport erected later but will try and double check - I would guess it is not asbestos. Are the hanger bolts rust proof? Edited April 13, 2019 by Mistral Quote Link to comment Share on other sites More sharing options...
___ Posted April 13, 2019 Share Posted April 13, 2019 1 minute ago, Mistral said: House was built in about 1978 but carport erected later but will try and double check - I would guess it is not asbestos. At the very least, wet it down when you drill. Use a cordless drill that doesn't have a big fan inside the motor that blows dust everywhere. 2 minutes ago, Mistral said: Are the hangar bolts rust proof? Stainless steel. They cost around R35 each. These I bought from another supplier, Jaco's upstream supplier was out of stock. So the hanger bolts and angle-brackets are solarworld stuff... the triangles and rails are Renusol. It married up pretty well in the end. But if you use Renusol hanger bolts it will make things even easier. Quote Link to comment Share on other sites More sharing options...
Mistral Posted April 13, 2019 Author Share Posted April 13, 2019 Good Tip. Tx. Quote Link to comment Share on other sites More sharing options...
Mistral Posted April 13, 2019 Author Share Posted April 13, 2019 At what angle should these panels be mounted? Quote Link to comment Share on other sites More sharing options...
___ Posted April 13, 2019 Share Posted April 13, 2019 1 minute ago, Mistral said: At what angle should these panels be mounted? It depends where you live. Mine is mounted 25°. Technically 30 or even 35 would be better for the area where I live. Renusol can supply different angles, essentially they just give you a shorter or longer piece to bolt into the back. Quote Link to comment Share on other sites More sharing options...
Mistral Posted April 13, 2019 Author Share Posted April 13, 2019 Cape Town? Quote Link to comment Share on other sites More sharing options...
___ Posted April 13, 2019 Share Posted April 13, 2019 (edited) 9 minutes ago, Mistral said: Cape Town? http://solarelectricityhandbook.com/solar-angle-calculator.html That suggests 10° in summer and 50° in winter. So if you aim right in the middle, that would mean 30°. That gets you optimal production in spring/autumn, with a little bit of loss in the other seasons. The loss can be calculated as the cosine of the angle. If the sun hits it spot-on (0 degrees from perpendicular), then cos(theta) = 1 (100%). If you are ten degrees off, you lose 2%. 20 degrees loses 6%. So at 30° you are quite optimal. For me aesthetics also plays a role, and a panel that's mounted at more than 30° feels too much like a sail to me. Edited April 13, 2019 by plonkster Quote Link to comment Share on other sites More sharing options...
Mistral Posted April 13, 2019 Author Share Posted April 13, 2019 I agree about the sail! We have peak wind gusts of up to 140kmh in winter when the north wester is pumping..... Quote Link to comment Share on other sites More sharing options...
SilverNodashi Posted April 14, 2019 Share Posted April 14, 2019 On 2019/04/13 at 12:07 PM, Mistral said: At what angle should these panels be mounted? Generally you angle the panels more or less on the latitude you live, +15 degrees for summer and -15 degrees for winter. So if Cape Town's latitude is -33, mount them at say -18 in summer and -48 in winter. IF you can, and your roof supports it, get a system with some adjustment. Most people can't so we mount how we can. If you can't have the flexibility, mount of winter. Quote Link to comment Share on other sites More sharing options...
Mistral Posted April 15, 2019 Author Share Posted April 15, 2019 Pics of Carport roof will be posted when the rain stops. Quote Link to comment Share on other sites More sharing options...
___ Posted April 15, 2019 Share Posted April 15, 2019 1 hour ago, Mistral said: Pics of Carport roof will be posted when the rain stops. In Cape Town? Bright and sunny today! Quote Link to comment Share on other sites More sharing options...
Mistral Posted April 16, 2019 Author Share Posted April 16, 2019 (edited) Had to wait for good light! Herewith pics of the carport reduced to 20% of their original quality. Edited April 16, 2019 by Mistral Quote Link to comment Share on other sites More sharing options...
Mistral Posted April 16, 2019 Author Share Posted April 16, 2019 Quote Link to comment Share on other sites More sharing options...
___ Posted April 16, 2019 Share Posted April 16, 2019 That is very similar to mine, though I think I have slightly beefier beams. There is a minimum beam thickness you need relative to the size of the hanger bolt. I can't really advise on that. But assuming it will hold, your setup will be similar to mine. Drill a hole on the top of the ridge right above the beam. Screw in the hanger bolt. It has a rubber seal on the top to help keep it tight. Then mount your triangles to it in the same manner. When working on the roof, use a long plank to spread your weight. Quote Link to comment Share on other sites More sharing options...
Mistral Posted April 16, 2019 Author Share Posted April 16, 2019 Thanks. I am a bit worried about the thickness of those beams - maybe the carport is not such a good idea.... Unfortunately the tiles on the main house roof are old and tend to crack. Quote Link to comment Share on other sites More sharing options...
___ Posted April 16, 2019 Share Posted April 16, 2019 10 minutes ago, Mistral said: Thanks. I am a bit worried about the thickness of those beams - maybe the carport is not such a good idea.... Retrofit a thicker one next to it and tie it into the main beam. My beams are almost 50mm wide, so I could sink my hangers directly into them. Here and there, where I deemed it necessary, I put in some support too from below. A small bit of pine shaped to fit. Hanger goes right through it. According to the IBC manual, if you use M10x200 hangers like I did, you have to sink the hanger between 40 and 65mm. Pre-drill with 7mm. So you need a rafter that will at least take that much screwed into it and have some meat left, probably 100mm in height at least. Quote Link to comment Share on other sites More sharing options...
Mistral Posted April 16, 2019 Author Share Posted April 16, 2019 Neat job! Quote Link to comment Share on other sites More sharing options...
___ Posted April 16, 2019 Share Posted April 16, 2019 3 minutes ago, Mistral said: Neat job! Thanks. There's still thing I could have done better Quote Link to comment Share on other sites More sharing options...
Mistral Posted April 17, 2019 Author Share Posted April 17, 2019 How best to tie into the main beams? Retrofit a thicker one next to it and tie it into the main beam. Quote Link to comment Share on other sites More sharing options...
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