sgt_woulds

Too true - too many monkeys not enough craftsmen. The adage 'never do to a customer's house that you wouldn't want done to your own' is one I've always worked to and tried to instil in apprentices, but I've worked with many so-called tradesmen of all types who couldn't give a toss as long as they got paid. Having said that, I've yet to come across any roof that is 100% waterproof but a properly installed and detailed membrane should keep out 99.99% 🙂

A valley is a likely area to leak due to the amount of water it will see. Have they fitted the dry valleys yet? Gable ladders are a strange location for issues unless the undercloak is not in place. As ever, pictures speak a thousand words...

The tiles and flashing form the primary waterproofing layer. In older houses this is also the only waterproofing, which is why traditional buildings have slates or plain tiles, both of which have greater overlaps and can resist wind-driven rain quite well. Wooden sarking boards were introduced in high exposure zones to prevent wind from blowing through one side of the roof and lifting tiles on tiles on the other. These were gradually replaced with paper and bituminous membranes that performed the same function but were cheaper and quicker to fix. As modern interlocking tiles were introduced, wind-driven rain became more of an issue, and the membranes became important as a secondary weathertight barrier. They became standard fit in all situations, but gradually changed to the breathable types. The membrane should provide good weather tightness until the roof proper is on but are not 100 % proof thanks to nail holes etc. The better types will have tape at the overlaps and a conscientious roofer will ensure there is a slight 'droop' between the rafters to ensure good runoff and tape penetrations and abutments if leaving exposed. In certain situations the membrane can be deleted, e.g. wood fibre insulating sarking boards above the rafters on a warm roof. Tiles still provide primary weatherproofing and the hydrophobic coating on the woodfibre is the secondary waterproofing layer. In any case, whatever is under the tiles is only ever a backup.

www.paintzero.com Make breathable paints that come as bags of powder - mix with water and off you go. Seems quite a good idea as unused paint powder can be stored easily until it's needed again, unlike large tins of paint that can go wrong. Crown were making bold claims, (probably still are) in their literature and website to push people to use their contract trade paints over freshly plastered walls as the paint was 'more breathable'. I couldn't find anything in the datasheets or the tins that gave the Sd or mu values. After a lot of back and forth they finally said: "We don’t measure the Sd value on our Trade paints as the paint will always have a low Sd value due to the nature of the paints. A couple of years ago we measured the Sd value on Covermatt and Crown Trade Matt and both of these had a Sd value of approx. 0.060. The measurements were carried out in our R&D lab. Please see table below for Sd value and the classifications Sd 0.060 Classification v 1 HIGH Classification Sd 1 HIGH The Covermatt, Trade Matt and Contract Matt are similar types of paints so I would expect the Contract Matt to have similar Sd value and classification as the other two paints." (sic)

If you are looking at building a house with natural materials like straw bales I assume you are happy to trade the low(ish) cost and complexity of the materials against the sheer amount of extra labour required? In which case, have you considered Cobbauge which would be similarly hands-on but not subject to the vagaries of straw bale quality and procurement?

That's not oversight, it's incompetence. It's about a lack of fundamental knowledge of how a PV system works. Any solar installer would check the system requirements before wiring the system. To complete the work they need to update the schematics of the system, (displayed at both inverter and mains incomer locations) to show how the panels and inverter are wired. If you've paid them on the basis of their alleged knowledge then they should be liable for the cost of scaffolding and rewiring to remove the redundant lengths of DC cable, (which will affect the performance of the system by a negligible amount, but the principle remains). They should also ensure that the inverter wiring and labelling are compliant with the wiring regs and MCS requirements and the grid regulations, (at least the ones in place when the system was first installed - G83 I think -G98 came in around 2020 from memory). I'm unsure if there are any additional requirements under the 18th edition WR - I've been out of the game for quite a while - but I'm sure there are some up to date electricians on here who can advise further...

Don't forget to check that your clamps will fall within the clamping zones specified by the panel manufacturer too. Clamps outside these zones may invalidate any warranty and may stress the cells/glass, and the frame may not provide the necessary uplift resistance. Not all solar panels can be clamped on the short sides - best to check. One thing to factor in when installing direct to the gutter - water rushes quicker down non-stick glass than other roofing materials and a large PV array can cause undersized gutters to overflow. Based on my own experience - and pessimism about future weather patterns - I would recommend deep flow gutters in general but certainly in this scenario.

If it were my panel on my roof I'd connect the two strings in series, then connect to one inverter. I'd have a bit of extra inefficiency from the additional cable length, but if I couldn't get on the roof to re-string it'd be the easiest option. However, I'm stating ON RECORD that I DO NOT recommend that you do this. It appears neither you nor your installer are competent enough to install panels or connect high-voltage DC to a grid-connected inverter. My recommendation is to have a suitable qualified PV installer commission the system for you.

You don't necessarily need a new inverter or more panels. 6 panels should fire up a single SB1200. Whether it will make the most efficient use of the panels, who can say. For maximum returns, a PV system should be designed, not just thrown together.

Yes. Who designed this system for you? Is the 'installer' a MCS competent person? If not, what are their qualifications for installing panels and working with high voltage DC? Why did they not check the requirements before connecting to the inverters?

The panels, string design, voltage and amperage would have been designed to match the inverter specifications. What panels did you have before? What were they rated at? How many panels in a string? (presumably 5 each but not necessarily) What is your string voltage and amperage now? Is the polarity correct? A string of six panels should have an open circuit voltage of 120 - 225 v and 10-15 Amp depending upon panel specs which should be fine on one of your SB1200's. These things are bullet proof, but keep the other one as a spare. Who has installed the panels? What are their qualifications? Are the clamps within the clamping zones of the panels? Have you run uplift and dead weight calculations to ensure the correct number of fixings and screw sizes to work with your roof timbers? Distance from roof edges and ridge? If the installation was poor before, did the original installers properly assess the roof structure? Most times not. [Back in those early cowboy days we turned down installs on some roofs rather than risk roof damage or panels flying off. Often the homeowner would call back later to say company 'XYZ' had fitted 'twice as many panels' as we had recommended but had gone out of business. We had quite a good business fixing all the badly installed panels during the solar crash...] Who is connecting the panels to the inverters? What connectors are they using? Are they original manufacturer or 'generic compatible' with the original connectors, (MC3 or MC4 depending upon the age of the inverter). NEVER mix and match connector types - there are plenty of examples of fires caused by incompatible 'compatibles'. What size cables? Are they double insulated and how do they enter the roof space, (are they mechanically protected, or just run under a tile?

Says a man who has never done it ! 🙂 Try shovelling 2 1/2 tons of it into wheelbarrows and making what feels like the equivalent of a round trip to the sun backwards and forwards! Geocell binds together making it incredibly hard to get a shovel in, (had to use a shallow frying pan in the end) - moving it was the hardest physical thing I've ever done. I'm saying this as an ex-roofer used to shifting tons of slates up onto a scaffold 'cos the boss was a tight old so-and-so who wouldn't pay for a Bumpa. Other than that, yes it's lovely and light...

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You could try the Geocell system (from Mike Wye) - although it would mean wheelbarrowing a ton of expanded glass rubble to your back garden which might be just as hard as pumping concrete there. Is very DIY-doable though: Back to Earth also do something similar: Solid floor insulation – How to create a solid, insulated floor - Back to Earth

Yes, but Egypt tends to have less rain - although I suppose the Pyramids and other buildings probably get sandblasted regularly! Lime render may stand up to extreme weathering - but I'd take the advice of an expert - there don't appear to be any on here at the moment... These walls will likely be seeing horizontal wind-driven rain on a regular basis - if a stone rain screen can be made to work it will probably require less maintenance than a Lime render. Scottish John - I've not heard of this being done with bales, but the situation will be similar to using a brick or stone face with a ventilated cavity on a timber frame building. Will need to be signed off by a structural engineer. I'm sure I read an article in a (very) old magazine where the owner used a drystone wall over rendered bales for a shed/study. Can't remember if/how it was tied in, but it's not beyond the wit of man. I wouldn't want to try it though - would be Mouse City... On a separate front, a rubble foundation would not only be cheaper and easier to self-build but might also reduce the embodied carbon count enough to justify using a more conventional structure/insulation without so much environmental guilt. To annoy the FUD brigade - this is quite often employed with Earth Bag construction which the OP could consider as a more weatherproof construction method, with suitable internal insulation 🙂