Thorfun

we have a sedum roof and a wild flower roof but I paid someone to do it for me as I got a good warranty for all the work and it wasn't something I wanted leaking! but ours is over habitable spaces and not a garage so I might've had a go if it was over a garage. I'm not really sure I can offer much advise but I put bits about it in our latest blog post: which might offer a few bits of insight. I would probably suggest to get the roof designed (or at least signed off) by some form of structural engineer as the weight of the sedum, growing medium and water can be quite substantial. I found this on the web when I was researching green roofs: “To support lightweight sedum green roof construction, your roof needs a loading capacity of at least 120 Kg per square metre. For a wildflower roof with a 150mm depth of the substrate, work on loading capacity of 250Kg per square metre.” Source: https://www.turfonline.co.uk/blog/green-roof-construction/

my builders merchant has said that they also stock OB1 which is cheaper. does it do the same job as CT1? anyone know the difference?

****! better get some more ordered then.

@WWilts buy in bulk as it will get used! 🙂

it's a pretty simple spreadsheet and I won't share but here's an image of the categories I got from the various TF companies. hope this helps and there were a few unknowns in there as well so it is very hard to compare like-for-like as most people find which is why build quality was so much more important than cost for us. once we'd narrowed down to these 4 companies we did site visits for each to get an idea of how they work.

38mm x 140mm CLS is cheaper than that. first site I found not far from me shows headline figure of £5/lm. I'm sure that could be reduced with quantities. https://www.mstc.co.uk/ex-50x150-cls-38-x-140-fin-sizes-4-8-only-70-pefc-certified-bmt-pefc-0277-cls26

our TF sole plates sit on coursing blocks and, as @Mr Punter said, it was at this stage that I was standing over the brickie ensuring everything was as level and square as possible to give the TF the best chance of fitting! I think the TF company needed to use packers in only 1 small bit where the brickie went awry as he didn't have the self-levelling laser level! 🤦‍♂️ in the end the TF company said the coursing blocks were spot on and it made the sole plate fitting a breeze for them which they (and I) were very happy about.

I did it the other way and just sent our BR drawings to various TF companies and then put the resulting quotes in to a spreadsheet and could then see which companies included stuff and which didn't etc. I could then go back to the ones that didn't include things and asked them to add that item. I figured that TF companies should know what's required to build a house better than I did and so basically left it up to them to tell me what I needed as a base line. but at the end of the day my decision on who to use came down to quality of work and gut feeling as to whether I could work with them more than price.

but the Solaredge batteries can't be islanded, right? so in a power cut you're limited to the PW2?

hmm...yeah. maybe I'll investigate getting an installer to do it and zero rate it. then I don't have to worry about reclaiming VAT. too many options and too many things going around my head!

I'm not sure, was just voicing concerns in response to other posts about batteries not being zero rated unless supplied as part of the PV. also our battery solution will most likely be supply only so I'll have to claim back from HMRC post completion (assuming I go down that route!). tbh, I have so much else to do and worry about that I'm trying not to think too much about the batteries and am giving it thought cycles as and when I have them spare.

thanks Dan. appreciate it. so my 9.5k isn't too far off the mark. I still think I'll go down the Lux Power and Pylontech route as I can't really afford 9.5k (and maybe + VAT as my PV is already installed as well) at the moment!

I'd be really interested, if you didn't mind sharing, what your quotes for the PW2 and install is when you get it. my recent quote was £9500 exc VAT which had gone up from £7500 18 months ago. not sure if the installer is taking the Mickey/doesn't want the job or that is now the going rate.

ok. I guess that's one for your structural engineer.

Happy wife, happy life! 😂 (Happy partner, happy life doesn't really work though, sorry.)

I don't get how your system is, in essence, any different to a SIPS panel or a twin-wall system? again to refer to MBC's drawings https://www.mbctimberframe.co.uk/passive-house/passive-wall/

wish I knew what you said now!

that's the thing isn't it. going to get my sparkie to install the battery system. Solar PV is already installed as per that G99 application. then the M&E consultants got taken over and are no longer doing batteries and so gave me a refund for the PW2 and dumped me to find someone else to do the work. that's what led me down this path! so I don't have an installer any more.

spoke to UKPN and they said new G99 application. guess I'll Google how to do that (after searching on here first of course. 😉 )

isn't loft roll for horizontal usage? might sag if installed vertically or diagonally between rafters? also you have to compare the lamda values of each. they may be different and so will need different thicknesses of each to get the same U-value.

I was talking about insulation below the slab. here's an example that many have on here offered by MBC https://www.mbctimberframe.co.uk/passive-house/passive-foundations/

don't forget the emotional cost of going for a flooring that you don't really want! if you'd wanted LVT then you'd have specified it to start with, right? so ditching the tiles (which is what you wanted) for LVT (which you didn't)* will have an emotional cost and impact. you might forever be thinking you really wished you had tiles? not sure you can put a financial cost on that. * assumed due to original decisions made about floor coverings

a whole new G99 application though? I've never done one of those before. 🤔

can't you just ask the tiler to install them and tell him you accept any risk in 'that area'?

on the subject of informing DNO....our G99 application that has been approved has this: if I'm not going for the PW2 any more but using another battery storage solution do I still need to inform the DNO? if so, is that a whole new G99 application?