Alan Ambrose

@Iceverge - thanks for taking the time to put up those examples - I think I'm going to have to carefully work through your examples to make sure I fully understand all your points I'm sure my brain was faster at some point than it is now ...

>>> And what does it look like if you move the polythene from in between the two different types of insulation to inside the PUR? Ah thanks, spotted (one of my) mistake(s) - their section drawing does show it where you suggest. That makes it look a bit better with only the OSB apparently having the main condensation risk...(left graph) I guess if I take the min temperature as +1.5C (which is the actual mean minimum from historical data in our area) instead of -5C then that makes it look even better (right graph). I suppose I'm assuming it'll dry out OK if the temperature occasionally dips below the usual minimum ..... this really does appear quite a complex subject

I'm no expert in tis but the Screwfix (No Nonsense) stuff I've used was (a) a bit too weak and crumbly once it set to use as an actual floor surface and (b) actually quite difficult to get accurately flat.

>>> pay an appropriate proportion of your bill - and keep the rest as a retainer Yeah, I've only done one piece of work with a supplier where there was an incentive arrangement agreed. In that case it worked well and everyone was happy. So, I'm also wondering about an after-the-fact incentive payment at the customer's discretion?

Hi, I'm trying to wrap my head around insulation options particularly re condensation. I think I kind of 'get it' re structural, installation & heat flow/temperature, but not not moisture. I get that as the temperature decreases from inside to outside (generally in the UK anyway), for any particular humidity level, at some point we reach dew point and get condensation. And 'that's bad'. But surely, as the temperature graphs must always fall off 'monotonically' i.e. always decreasing from inside to outside then we're going to hit the dew point at some position in the wall build-up? Here's a commercial example. If I've understood their literature then the build-up looks like this: and crunches out something like this: - and the temperature and humidity graphs look like this: That is, 'not so happy'. Any thoughts? TIA, Alan

Yeah, I think you’re right - can you call her to check?

Well that's interesting, I didn't know they published their pricing algorithm. I'm not sure I understand though why there should be a 14p uplift from 4-7pm in addition to the wholesale price? That seems like double counting and/or subsidising the rest of their customers.

Just to add a bit of balance (and to state the obvious) - of course, structural warranties are generally only for 10 years. This means, that the vast majority of UK houses (i.e. ones over 10 years old) get sold without one. What's more, structural warranties only cover structural problems. Then, supposing you find a structural problem between 3 and 10 years out - what do you think your chances are of claiming on the warranty after the warranty company has argued 'no it wasn't bad structural design, it was bad workmanship' etc etc etc. That is, the warranty won't be 100% protection - 50% maybe? I think I would dig into the detailed problems and see which really bother you and the surveyor. Negotiate money off to cover these if you can - because 'cash buyers only' reduces the available market. Maybe contact the builder and ask a few polite questions to cover some unknowns. See if the seller wants to provide an architect's or SE's cert - again these are not 100% watertight. Life is all a bit of a risk and even if you take all the insurance and make all the mitigations you can, there'll still be uncovered risk - on this and every other house purchase. Take a view of seller and builder integrity. By all means go in with your eyes open and as best informed as you can be, then make your decision bearing in mind how much you want the house and how much risk you're happy to bear - warranty or not.

As I've been attempting to nail down details of my build and I'm coming across an increasing number of 'Government', 'Industry' and for want of a better word/acronym 'NGO' organisations. Some of them make 'the rules' and/or are big influencers on people who have power (e.g. building control). As I've been looking at, say, Part O, I've been wondering 'where do these rules come from', 'who's making them', 'who's running these organisations', 'who owns them', 'what authority do they have', 'which get government funding', 'which are really for-profit masquerading as something else', 'which are really scams' etc etc etc. Maybe everyone else just accepts 'the rules' and gets on with it ? Does anyone have a sense of the landscape and/or answers to any of the questions?

Thanks Ian for your thoughts. >>> Why not just go with 300mm I-Joists, full of cellulose. A bit like this? I can get within 8% of the previous number with 373mm joists and only lose a cm: I read the chapters on ventilation and moisture in The Passivhaus Handbook over the weekend, but I am obviously still not quite getting it... BTW does this kind of join handle the SIP cold bridging problem?

Hi, Would anyone care to comment on this insulation stack-up, which I am considering for both walls and roof (walls with horizontal board for rain screen rather than pantiles)? Essentially SIP over cellulose using posi joists as Larsen truss. The idea is to use some PIR to reduce the overall wall thickness while maintaining a reasonable decrement delay / phase shift. This is all meant to be hanging outboard of an Oak frame which is also the structural support. BTW I chose Isocell as the nearest thing to Warmcel / I think 'Lamination' in ubakus is probably ply / I don't know why ubakus looks like it has put in an extra layer of wood underneath the pantiles - but I don't think it makes any difference anyway as the cavity beneath is ventilated. I was also thinking of using the posi joists / Warmcel as service layer rather than have a separate one. I've included an extra ply layer inboard of the plasterboard (like our Scandinavian brothers) to allow easy shelf support etc. It still looks there's a condensation problem - any ideas? Is the optimum decrement delay / phase shift 12 hours (for max attenuation) or is a longer number better? TIA, Alan

>>> vector sum metering is guaranteed by the standard Ah, so in a sense, his HP man is 'right' - that is the DNO will 'exchange' your export for import at zero price difference.

Well anything is possible, but you probably won’t like the cost and/or performance. The problem is that RTDs are usually used as small-signal devices to avoid self-heating - think tiny cables, screening, short distances to avoid noise pick-up etc. Sure, you can convert to digital and send IP/serial etc over wireless. But you’ll probably need a custom-made device to convert from digital back to small signal again with PT100 curve characteristics. Any other input options to your HP? RS485, Modbus, 0-10V etc?

Personally I would take the solid ash or oak anytime and treat any movement as evidence of 'life'. It's a funny thing, but antique dealers tell me they get far more money for the 'wonky' chairs they sell.

I guess 'our' kind of houses are, unfortunately, few-and-far between, so there's simply little exposure to good building practice or a lot of the more modern equipment, materials, and techniques we use. I think most customers for building trades don't have any idea of what quality they're getting - they tend to judge by contractor's politeness, cleanliness of their vans, how much they tidy up, how well written their quotes are etc etc. So, as we're leading the housing quality race, it would be right that central and local government cut us some slack e.g. like restricting Part O to the high-rise flat builders and the modern estate builders.

>>> the conumer unit will put power to whatever phase is calling for it... Hmmm, nonsense - in the sense that it can’t move power from one phase to another. So, that could leave you exporting on 2 phases while you import on the phase the HP is connected too. Which may have a cost penalty unless your supplier does the net-metering thing. ideally you use all PV power you generate on site first *before* sending some back to the grid. This added complexity of phase balancing and contractors being less familiar with 3P inverters, HPs, car chargers etc is one of the downsides of 3P.

>>> Arguing with stupid people, who are so stupid they don't realise how stupid they are. +99

Guys you don't seem to fully get the concept of 'O' in SWMBO.

>>> set the handrail on the balustrade higher than the 1100 mm required by building regs to allow for the height of the decking. You do know that thinking ahead is actually forbidden on BH forum?

Wow, that's nice :). Yeah, I could retire there...

>>> a bunch of trained otters from the zoo Looking for a more skilled workforce? >>> So just how bad is the cold bridge created by the ridge board? You can work it out approximately, if you can be bothered (or get someone to do it for you). I would guess not very much - add maybe 3-5% to roof w/m^2? Maybe there some internal insulation detail you can figure - the RSJ was always going to be a cold bridge anyway, so some beefed-up and specific insulation detail under that?

Personally I hate fibreglass after a bunch of experience with glass, resin and gf boats in my youth. You'll be sheltered from the installation yuk, but I wonder what the real expected lifetime is? Used as a terrace, I would expect it to crack under point loads, then leak, then need replacing.

If you ever need high bandwidth to any particular point in your house then proper network cable is a must. Once we got fibre here it took me a bit of work to get all that bandwidth back to my study etc. You need a fibre router, 1 gig hubs, and … cable. Shared wifi will be fine for internet browsing etc but it won’t handle the full bandwidth of fibre. Cable also allows poe to cameras, access points etc and avoids you having to have mains power near them. Also wired doorbells, thermostats etc avoids all that BS with batteries and the spottiness of low bandwidth connections. I think dependence on wifi is short-sighted.

Nice & congrats.

Congrats, and you'll find the people here very skilled and very helpful. A shot of the view please, just to make us jealous you understand?