Jeremy Harris

My suggestion would be to do a normal U value calculation, taking the R values of all the layers, adding them together and them taking the inverse to get the U value.

Congratulations! Over the first hurdle in what will probably be a few, but far and away the most worrying in many respects.

From the chat I had this morning with my ISP, they said much the same, but added that they believed that, under the new legislation, if you get less than 10 Mbs, then the charge from Openreach to run FTTP would be capped. It remains to be seen what that cap would be, but if it's of the order of a couple of hundred pounds then I'd pay it, as the current 4 to 6 MBs is pretty dire, and that's on VDSL and FTTC. On ADSL we were struggling to get half that.

+1 to the above from @Onoff, I've also used them for years, in fact three of my torches are still running on their cells and they must be at least 6 or 7 years old, maybe older.

I've just looked at the drawings again, a bit more closely, and found that the orientation of the manifold in the drawing is 180 degrees out compared to the installation photo. That suggests that the always on bypass loop may really be the bathroom, rather than a bedroom.

I read this, then rang my ISP to find out what was likely to happen (we don't get 10 Mbs even with VDSL and FTTC). They were quite helpful and said that as they understood it, the chances were that OpenReach would be forced to offer FTTP for those who requested it, but they had no idea as to the cost. They did say that the chances were that we would pass the initial installation feasibility test, as access from the existing roadside cabinet to inside our house was straightforward; a short length of overhead fibre and then down through the ducts we already have. Be interesting to see how it pans out, as we could desperately do with better download speeds.

Sounds high, to me. We had a very much bigger retaining wall built, using double rows of 220mm hollow blocks, filled with rebar and concrete, for not much more than that. I think the base cost of our retaining wall, less the cost of the rendered finish, was around £25k or so. There are photos in these blog entries that show the scale of it - it was around 2.5m high and the total wall length was around 42m, IIRC. http://www.mayfly.eu/2013/07/part-six-there-we-were-digging-this-hole/ http://www.mayfly.eu/2013/07/part-seven-pouring-concrete-3/ http://www.mayfly.eu/2013/07/part-eight-the-wall/

It means that the right most circuit is always on. Whether it is as per the schematic and a bedroom needs to be checked, it's possible that the manifold pipes were not connected in the order shown on the plan. Changing it is easy, just swap the cap on the right most circuit with one of the actuators, whichever circuit you want to act as the bypass and be on all the time. You may need to change the wiring of this actuator to make sure it's now on the bedroom zone, if you have zone switching.

Some of the companies that pull the "eternal sale" trick really should be tackled, IMHO. We went and looked at a lot of furniture in Oak Furniture Land, about a couple of months before one of their sales, at a time when they had no signs up indicating any sale or promotions. I wrote down the name and price of every item were were interested in, typed up a spreadsheet then waited untl the January sale, that was widely advertised on TV. Every single item was EXACTLY the same price as it had been long before the sale................ I had a bit of a public argument with one of the sales guys, who tried all sorts of bluff and bluster to "explain" why the prices were the same, and he even went so far as to offer us a "£150 free gift" (a mirror that wasn't worth £20 and which we didn't want, anyway). We walked out and vowed that we'd never, ever buy anything from them again, on a point of principle. The interesting thing was that we found a local, independent, oak and pine furniture warehouse and they had EXACTLY the same range as Oak Furniture Land, at around the same initial prices. When I explained that we were looking to buy over £4,000 worth, potentially, we got a massive discount off the listed prices and ended up saving around 25% over the "sale" prices in the other place. We also had really good personal service from them, with them delivering, unpacking, checking and assembling every item, free of charge. My understanding is that Oak Furniture Land just deliver the stuff and leave you to unpack it etc.

Yes. 7.5V is too high, the maximum voltage it will normally see with brand new batteries is around 6.2 V. 350 mA is probably a bit on the low side, too. The other thing to watch is that the polarity of any supply you use is correct. The normal convention is now that the centre pin is the positive, but this isn't always adhered to so is worth checking before you plug anything in. To add to the problem, there is a wide range of different sizes of power plug, and even common external barrel diameter ones, like 5.5mm, can have either a 2.1mm or 2.5mm internal pin/socket, making them incompatible with each other in some cases (some have springs that may make up the 0.4mm difference in pin size).

4 AAA cells when brand new will be around 6.2 V, when effectively discharged they would be around 5 V, so a 6 V supply with the correct plug should do the job. Hard to know what the current demand is, but as the cells are only AAA, which are not that high a capacity, I'd take a guesstimate that a supply capably of delivering at least 1 A should be fine.

We bought a new house (had been a self-build, by a "serial self-builder") that had an architects certificate. We had no problems at all getting a mortgage on it; every lender I approached was happy to accept it, so I'm convinced that, in practice, all this fuss made about the importance of warranties is exaggerated. Lenders are not daft, and must know full well by now that something like an NHBC warranty is a worthless bit of paper in reality.

Nothing like that here. Just a declaration that it was a self-build.

We don't have a self-build mortgage, neither did we have a problem with a CiL exemption, and we don't have a warranty, mainly becuase we once bought a new house with an NHBC warranty and when we tried to claim we found it wasn't worth the paper it was written on. What are the links between CiL exemption, a warranty and a self-build mortgage? I haven't seen any connection between these at all. All the local authority needed was to be assured our build was a self build (easy, we told them, both directly and in the planning application). No one ever asked whether we had a warranty or a self-build mortgage, either, and I can't see why a local authority would be interested in either.

Generally it's a hard question to answer, as it's not just the U value that matters, but the overall heat loss. Much of this will be ventilation loss, and there is very definitely a trade off between the volume of a house and the insulation level needed - as buildings get larger insulation values become less important and ventilation heat loss becomes more important. It's partly why I wrote the simple heat loss spreadsheet, as that allows you to fairly quickly see the effects of changing things. You can pretty quickly do "what if" checks to see what effect making the walls, roof or floor better insulated have, or what effect improving the windows has (although bear in mind that there is a subjective comfort factor with having 3G glazing with two low e panes that is not shown by the U value difference).

It's always a trade off between performance and cost, but windows and doors are areas where the benefits of improved performance are generally greater than elsewhere, not just because the losses are lower, but mainly because they improve the comfort level more than the bare figures tend to suggest. The impact of having two layers of low e glass, reflecting long wavelength IR back into the house, are very noticeable indeed, and add a fair bit to the way the house feels in cold weather. The argument that it's not worth improving insulation elsewhere just because doors and windows won't be as good doesn't really stack up at all, as the areas of all the other surfaces are so much greater than that of the glazing. There are also other factors to bear in mind, like ensuring that the decrement delay factor of the wall and roof construction and insulation is adequately long, as that makes a significant difference to the comfort level.

FWIW, I did layout drawings for both floors for the drain runs (they are the immovable things, usually) the ventilation duct runs (the next biggest items) and the hot and cold plumbing runs. I didn't do wiring run drawings, but did produce drawings showing the location of every outlet and switch, plus the consumer unit etc. All told I would guess I spent around 20 hours doing drawings, and left the wiring runs to be sorted by the electrician. This was for a house that's a lot smaller, 130m². The problems get more complex as the house size increases, particularly where there may be "pinch points" where several services have to run close to each other. £6k sounds a bit on the high side, but then you're in an expensive area plus it's a big house, and both of those factors would tend to push the price up.

I've changed it to a link to satisfy the over-sensitive souls, but frankly I think this level of sensitivity to something so mild is way OTT...............

Frankly I've used the word fuckwit before, and I'm not sure it really warrants censorship. Anyone who has been on any building site will have heard far, far worse, and this is a building and renovation forum.................... I can link to it if we REALLY feel that's needed, but in my view I don't think it's really necessary to just change it to a link.

I don't think we'll see a change to the Building Regulations, as they are fine as they are, in the main. The problem areas are that the Approved Documents are not properly understood; not everyone realises that they are not the regulations and they are not legally binding directions or instructions, and also that the inspection regime can be inflexible and less than competent on occasion. If inspectors stuck to inspecting for compliance with the Building Regulations themselves, rather than a few being obsessed with the Approved Documents, then things would be a great deal easier for self-builders looking to use new methods of construction.

OK, edited for the prudes with no sense of humour, so you now have to click a link: https://flic.kr/p/22CTv4H

Nothing to do with duct loss at all, and everything to do with the positioning of MVHR fresh air terminals and the way the air circulates. If you could reconfigure the ducting, to switch the fresh air feeds selectively to the specific rooms that have the incidental/solar gain issue, then it might have a greater impact, but the evenly distributed nature of MVHR means that cool air is distributed from several terminals in rooms that don't actually need much cooling. This is all discussed in depth in older threads here, but to reiterate, before we fitted the long wavelength IR reflective external film to the front glazing, we had typical cold, but sunny, late autumn, early spring, days when we would get well over 2 kW of solar gain in the hall way, just from that glazing alone. It wasn't a problem in summer as the shading from the extended roof overhang worked OK. Also, and again discussed at length in other threads, we had a surprising amount of solar gain from the two east facing windows, as I'd overlooked the effect of clear morning air and the duration of the sun from the east. Having around 300 to 400 W/m2 coming in through around 3m2 of glazing added a significant heat input too (and, as discussed in other threads, we fitted external long wavelength IR reflective film to the east-facing bedroom window to mitigate this). The east windows were in a bedroom (with a single fresh air terminal) and in the kitchen (with no fresh air terminals). At 18 deg C surface temperature there is a near zero risk of floor surface condensation, so much so that we've never had (AFAIK) any room air conditions where condensation would occur on a surface at 18 deg C (and is why I selected that temperature, as mentioned in the other threads on this). The RH would have to be way, way higher than we have ever seen, even when cooking, for ground floor condensation to be an issue at this temperature. The duct heat exchangers have a capacity that is similar to the Genvex air to air heat pump, as the limit is really set by the air flow rate, but they do have the advantage of being cheaper. coupled with the floor cooling and run from the ASHP, I would expect that the performance would be around the same. One option might be to separate out the duct coolers from the MVHR and have a separate system that recirculated air from warm rooms through local fan coil units (with condensate trays). This would address the issue where incidental heating is localised to just two or three spaces in the house (which was certainly the case for us). The bottom line is that shading is a better option. Had we had the option to fit external blinds (planning constraints meant this wasn't an option) then they would have been my first choice. I stayed in an apartment in Portugal with electrically operated external blinds and they were extremely effective, and had the added bonus of increasing security.

sorry, looks like I made an arithmetic error, comes from working in a hurry over a glass of wine!. Our Genvex also has a max boost of 300 m3/h, but will the outside temperature be 5 deg lower than the target room temp when you need cooling? My experience is that it doesn't, and that just having the MVHR on bypass, on (noisy) full boost doesn't make a great deal of difference during the day. It works OK for night purging, but for day time cooling the active air to air heat pump tends to work a bit better, as that can deliver air at around 12 deg C (pulling it through the bypass first, then cooling it with a nominal cooling capacity of around 1200 to 1400 w). We've discussed adding duct heat exchangers here several times, and they do make a lot of sense. If I were doing in again I'd probably have fitted a heating/cooling duct heat exchanger, with a condensate tray and drain (there are some links in other threads here where we've discussed this). The bottom line is that, in practice, the Genvex Premium 1L is nowhere near enough to make a rapid difference, even on full boost. It's oversized for our house, too. The floor cooling, on the other hand, is massively more effective at cooling the house. In cooling mode I run it with a flow temperature of 12 deg C and that gives a coolest floor surface temperature of around 18 deg C, so there is no realistic condensation risk for any probably house air relative humidity level. Floor cooling works better than I expected and is our primary cooling system in very hot weather.

Email the link to one of my throwaway email addresses, purchases1@mayfly.eu, I'll upload it to flickr or postimg and then post a link.

The interim report says this: and then goes on to say: I don't think I'd disagree with those statements at all. There are many times when I've reverted to looking at the letter of the underlying law, rather than the guidance in the Approved Documents, and have gone on to make the case that compliance with the law is all that matters, not rigid compliance to the suggested methods of compliance in the Approved Documents. One interesting point made is that private building control companies have NO power of enforcement, yet LABC do. That alone is a curious situation that encourages larger construction companies to use private building control companies, knowing full well that they cannot enforce any action over any non-compliance they pick up................