Redbeard

With similar misgivings I laid some for my son at his request. They looked quite ... OK. He was very happy with them and I guess I could learn to live with them! Ours were from Wickes, and I think I have a box over, so I'll take a look and report back on details.

Until the latest revision it was very clear. The roof U value target was split into 'at rafter level' and on top of first floor ceilings (cannot remember the exact wording for the latter). At rafter level it was 0.18 and 'on the flat' 0.16. Now there is no distinction made so one has to assume that the target for both is 0.16. The fact that a ceiling at rafter level (a skeiling) is a ceiling has not, in my view, changed.

@Russdl, what was the minus 12.6 degree 'item'? How cold is it in Salisbury at the moment? Had a guess or two but the siting (above a bedroom) seems illogical for my guess.

Lots who aren't lads too! SE = Structural Engineering.

For fiddly little cut-outs you can do a lot worse than a bread-knife. The special insulation (hand)saws you can buy are effectively just that. You can buy insulation blades for reciprocating saws but I challenge you to stop the blade waggling (i.e. your cut looks great on 'your' side of the board and is say 50mm out at the back!). I gather Festool do something wonderful but I am afraid i have no details. Yes you can fill with expanding foam, but the lambda value is not (AFAIK) the same, so keep it to a minimum. However if you try to fill really narrow joints (say less than 3mm wide) you will probably find yopur foam only goes a few mm deep. Do some test-pieces. Good luck!

Very much agree with @ProDave. While the buyer may accept that it complies (or more correctly is exempt from some bits) it does not alter the fact that the thinking behind an exempt conservatory is that it is effectively 'outside' (hence the external doors between it and the house and the separately-controlled heating (so that it does not act as a heat-dump for the C htg). It will still be cold/expensive to heat and (depending on the orientation) possibly blazing hot at times too. Yes, it does not fill you with confidence when a seller does not know the difference between a lambda value (W/mK) and a U value (W/m2K).

It may not be that great, as there are other views 'out there' on t'internet. Someone I know had this done, although they also had no separating doors, which was definitely non-compliant. As I said, *as far as I can see* there are no stipulations, but others may have other views. I hope you can get it sorted to the satisfaction of your buyer.

Hi and welcome. Your BCO is right. All you need is here: https://www.planningportal.co.uk/permission/common-projects/conservatories/building-regulations There is no stipulation AFAICS as to what you can put in a 'conservatory'. Therefore the presence of kitchen paraphernalia is immaterial as long as you have the compliant doors, glazing, elecs and independednt heating 'system'.

Ah, sorry, read that too quickly. You are saying they have ignored the spec of 120 and fitted 100? If so ask them to fit as per the spec which will get you 0.18. 100mm won't, unless there's something else not listed.

** Ventilation externally of course if you do *not* insulate the flue! We did both insulation to the flue and IWI.

Yes, I poured it down and capped the flue. You could ventilate externally and apply IWI to the full chimney breast.

Most PIR insulants are credited with a lambda of 0.022W/mK. 0.12(m)/0.022 = R = 5.45. 1/R = U = 0.183W/m2K. You can also take into account any othere elements which don't have cold ventilation air flowing through them, so that's the ceiling, deck board, EPDM, internal and external surface resistances. All that should just get you 0.18. Assume you already have Bldg Regs approval (prior to the June changes (if you are in England).

If you are happy that it is dry you could insulate from the top with vermiculite or EPS beads. I did this for a client 5 years ago and no issues. The flaw I find with ventilating unused flues as per DIY guides is that you introduce potentially warm moist air into the flue where it can potentially condense as the flue cools near the bedroom ceiling line.

Got one in Sheffield a few weeks ago. Search IBC Sheffield Ebay. Co. is in Darnall. Not *that* far from Chesterfield!

Hi, Have you done a heat-loss calc? What's the worst-case scenario at 21 internally and say -5 externally (or whatever parameters you want to work to)? If less than 16 or 17kW then you are OK for a single-phase ASHP. You probably know you can keep the walls breathable and improve the insulation using rigid wood-fibre, cork or (with a rather worse lambda value) hemp/lime. However if you simply want exposed stone walls then you won't want to cover them with anything. Is the existing render lime or sand/cement based? If lime and not too cracked you could treat it as a parge (air-tightness) coat for wood-fibre.

Would this help? https://www.susdrain.org/resources/SuDS_Manual.html The original CIRIA document is of some age (I knew it in 2008) but there is ref to an update. Hope it helps. I agree re the 'drainage field' and foul, but is this perhaps whatever the 'modern' version of a leach-field is, after a sewage treatment plant?

If it is not for seriously long term, how about turning those studs into Larsen Trusses (spaced studs) and filling with 300 cheapest-you-can-get mineral wool? If you are just wanting it to last a year don't even worry too much about VCLs and so on. You will have to do something to isolate the insulation from the (damp) plinth walls, but I would suggest don't do it with polythene (risk of condensation on the cold side of the 'sandwich'). I would definitely do a floating floor (say T & G OSB on 50 PIR) but then that will be 'dead money' unless you can find a late phase of your build in which you can re-use the materials. Are you going to insulate the ceiling/roof? Maybe that could be spaced studs too. I don't think I would 'do' MVHR in this case unless I found a really really cheap unit.

It suggests that you can have a monopitch roof sloping 2.5-3m, but I would suggest a Planning app to get what you really want, if that does not fall under PD. I did that for my shed. Within 1m of the boundary, 3m @: eaves (and ridge height 4m). No problem (except the 8+ week wait for it to be transferred from the 'in' to the 'out' tray!).

Hi @richo106. You have not attached anything so we cannot see what you want your 'large glass front' to look like.

jimal1969: https://www.google.com/search?q=lulu+'shout'&oq=lulu+'shout'&aqs=chrome..69i57j0i22i30l9.6577j0j7&sourceid=chrome&ie=UTF-8#cobssid=s It was the w-ee-e-ll that did it. ''but surely if treated and untreated is the same price, treated would be a better bet??'' The feeling I have on timber treatment is that it contains stuff designed to kill things and if those things are very very unlikely to be there then it's a chemical I can keep out of the (or at least my, immediate) environment.

We-e-e-e-ll... (no, not Lulu, for those of a certain age) (explanation available on request)... OK, so pressure treatment is no longer CCA (Copper, Chrome and Arsenic) but whatever treatment is there may not be necessary in your circs. My general feeling is that if you are not exposing timber to potentially aggressive conditions you don't need to treat it against them. My timber-framed extension will have no treated timber in, and neither have a few extensions and TF buildings which I have helped build over the last 15 years. I would not buy treated for mine even if it were available at the same price.

Hmm... Strange. However: 10-12 years ago a fairly well-proven rule-of-thumb assumption was about 750kWh/kWp in propitious conditions. Again another rule of thumb is (was) that you could go to SW or SE with a loss of only 5-10%. Outputs per kWp of what we are getting now (I am not up to date, but 850 - 900kWh seems reasonably common) were not, AFAIK, around then. The sums work for me (within a few kWh) if I assume 240W per panel and a 5% drop-off from due S. As to whether the FIT £ is right for that size of array you could 'unwrap' that figure using RPI for each year going back. If I remember rightly the year 1 FIT was 41.3p, rising to 43 (?.3) in 2011.

Hi and welcome from another relative newbie. As intimated by @Mr Punter I would strongly suggest that you do a Whole House Plan (detailing your wishes, target U values, where the air-tightness layer will be, what it will be, *how* it will be) at the outset, even if you have to do a room at a time. I am 35 years into my 'incremental retrofit'! Doing the Whole House Plan allows you to identify the 'edges' - those perimeter bits which the next stage of work will need to connect to when you get round to it in however many years. There are some who believe that 'move out and rip out' is the only answer. If that were the case then 99% of my clients over the last 20 years would have done nothing. You do have to be careful not to leave gaps and potential 'moist edges', but with care (and documentation) it can be done. In particular note that the tighter you make it the less you can rely on 'unintentional ventilation', so design in your ventilation 'system' (even if it's not MVHR) sooner rather than later. Enjoy it; it's fun!

A common approach is to lay the VCL on top of the bottom OSB deck, before laying the insulation on. A not uncommon approach is not to be too careful where the long screws go, between top deck, bottom deck and (supposedly) into the joists/rafters, meaning that the 'sandwich' is mainly fixed between OSB and OSB, leaving it insufficiently fixed down. I suspect this is why the 'deck is pierced with nails in quite a number of places'. In the circs it may be that a retrofitted polythene VCL may not be fitted too 'tightly', and that in these circs the 'VCL paint' might be OK. I normally worry about having gypsum (which, in my view, 'sucks' moisture) in a 'sandwich', but in terms of 2 'evils' the VCL paint may be the lesser. It will also allow you to connect wall VCL with ceiling, which can be very tricky if the VCL is above the bottom deck.

When you say ' I was intentionally NOT insulating between the floors' I assume you mean 'the *walls* between the floors. If so this is what was done a long time ago, but is not common IWI practice now, which is to wrap the entire envelope (preferably externally but sometimes internally), including the interstices between floors. I am a retrofit practitioner, but I cannot claim to be a moisture expert. I defer to WUFI when I can (if I can find a practitioner to do the calcs (leads appreciated!). Have you got pics or diagrams of your situation and your proposals? What thickness of WF are you using? Rigid, hard-to-the-wall, or flexi between studs?