Jeremy Harris

That's a very useful reminder, as I think someone here (may have been on the old forum) got caught out by not following the precise paper trail needed in order to get the CIL exemption. IIRC, temp wrote something on this around the time the CIL exemption was introduced, highlighting the potential pitfalls for the unwary. I'll have a poke around and see if I can find it, as it would be useful to compile a "sticky" here as a reminder, in bullet point form, as to how we can avoid getting caught out. The same sort of thinking seems to be behind the HMRC and VAT reclaims I've recently found - unlike the VAT helpline (who are very good) the reclaim people are both obstructive and slow, in my recent experience. I've also found that the local authority tried very hard (to the extent of breaking into our security fenced site, with no PPE worn, one evening) to try and get evidence to charge Council Tax as early as possible during the construction of your build. Without a shadow of doubt they are after a much money from you as they can get!

Pity you didn't actually read what I wrote, it sort of spoils the effect you were aiming for. I didn't say there was NO cold bridging with Dave's build, what I wrote was this: Note that the phrase I used was "largely mitigated". There's an important and significant difference between what you allege I wrote and what I actually wrote. Accuracy seems something that some here have a problem with, and I think it's important that if being critical one should at least make the effort to be accurate in that criticism. As you're well aware, you can reduce cold-bridging to such a degree with a twin-stud wall that, for all practical purposes, it's not even worth the effort of calculating.

Who's confusing cold bridging vs basic heat loss? Not me, that's for sure! As a retired senior principal scientist I'm reasonable aware of the basic physics of heat transmission.............................

Over the years I've found that it's the fast-cure foams that seem to create the most pressure. I filled some flotation chambers in a GRP boat decades ago and managed to put bulges in the hull! I was filling these tubes (which were the gunwales for an experimental "no wood" rowing boat) really just to prevent them getting water inside. If anyone's inetrested I wrote the design and build up in an article in Watercraft magazine a few years ago, and there's some details of the design and build on this forum thread: http://uk-hbbr-forum.967333.n3.nabble.com/The-quot-Aerowherry-quot-a-lightweight-rowing-boat-was-going-to-be-a-canoe-td2424625.html Here's a photo of me rowing her up the Hamble to the pub:

Not only will the BI not ask, but there's no easy way to tell from just looking at a joint. There are times when 100% compliance with the regs is essential, and a very good thing, but equally there are times when it's best to just take an easier, simpler and just as safe route and not worry too much about the regs. I can give an example, and one that I did raise with my BI. Our 70 litre buffer tank is on the ground floor, and is indirect, but filled with inhibitor, because the coil in it is filled with antifreeze for the ASHP (and there was no way I was paying hundreds of pounds for 70 litres worth of antifreeze!). All it feeds is the UFH and a PHE for pre-heating the incoming cold water supply to the main DHW heating system. The regulation way of installing this would have been to fit a small header tank, with float valve, overflow etc, in the first floor, in-roof, service room. However, space up there was limited. The buffer tank was rated at, IIRC, 1.5 bar maximum working pressure (enough to allow it to be used on the ground floor of a three storey house with a loft-mounted header tank). I decided to use it as an unvented cylinder, operating at 0.5 bar, so fitted a larger than normal expansion vessel, filler loop etc, a 1 bar pressure gauge and a 1.5 bar pressure relief valve, discharging into a tundish to a drain. Building inspector was of the view that running at 0.5 bar meant it wasn't a pressurised system, and wasn't the slightest bit bothered about it. Technically it needed a part G sign off, but if your BI signs it off on inspection that's covered.

The case on hers is one of those that form a stand, I've a feeling it's the genuine Apple one though, that cost an arm and a leg. I didn't buy it - I use a cheap Sony Xperia Z tablet, bought "refurbished" from Morgan's, with a case from ebay, and loaded with a de-Googled completely open source version of Android, but then: a) I'm a cheapskate b) I like devices that can communicate with pretty much any device or network, accept µSD card storage, µUSB OTG sticks, don't use proprietary connectors and don't infringe on my privacy...........

I missed this earlier, but I did something similar when filling some alloy tubes with can foam, and it's a trick that may be worth passing on here. The tubes I wanted to fill were 1" diameter 16g wall and just over 5m long (sorry for the mixture of units, but alloy tubes are often sold in imperial diameter and wall thickness but metric length...........). I got a bit of cheap 8mm PVC clear flexible pipe and found that it was a nice tight push fit on to my foam gun nozzle. I didn't block either end of the tube I was filling, but started from the centre, by having just over 2.5m of pipe on the gun. The technique was to squirt (slowly!) whilst pulling the pipe out. Having done this from the centre to one end, I did the same from the other end. It worked a treat. What I found didn't work was to try and fill the tube from one end, moving the gun back the whole 5m+. I tried it, made a mess, had to throw the bit of flexible pipe away and clean out the tube, before using the "centre out" method. I can't see why this shouldn't work for filling things like cills, as if you go slowly, pulling the pipe out as you go, there's very little risk of a pressure build up.

There's a BS method for calculating the λ for a thin air void, I mentioned it in the post above, that might be worth passing on to your AT. There's more detail of the method on the BRE website, in fact I think there's even a downloadable document detailing the methods to apply and their limitations.

My personal view is that, even if it's fine for the residents (and pets etc) of the house right now, how safe would it be in the future? In our case, the power outlets will most probably be used to charge my other's half iPad (hence the reason for getting the one with USB outlets) so she can look at it whilst cooking, or for powering the little hand-held whizzer food mixer thing. Both probably low risk in terms of safety hazard if they were pulled off the work surface (although a small child and the food mixer thing would be a damned dangerous combination). The consequences of catching an iPad charging lead from a side-mounted socket and smashing it on the stone floor would be expensive and that was my main reason for fitting the pop-up. It so happens that it makes a very good iPad prop as well, making it easier to see the screen when cooking.

I'm sure Dave will be along soon, but I'm pretty sure when he came up with this construction method there was a fair bit of discussion about it, probably on ebuild before it closed down. The thickness of wood fibre on the outside does have a pretty big impact on reducing the cold bridging, if my PC wasn't still in the process of being rebuilt from a backup right now (long story - lost the boot HDD four days ago!) I'd probably be able to find the calcs, as I think I did some way back before Dave started building to see how effective the construction scheme he'd come up with was, and concluded that it was reasonably good. Not as good as a twin wall system, but cheaper to build, and importantly from Dave's perspective in his location, could be relatively easily built on site, rather than use large and expensive to transport prefabricated sections as we did.

That makes a tiny bit more sense. For those thinking of putting sockets on the outside of an island, though, I'll just relate my experience in my workshop. I fitted 6 outlets just under the top of my bench, set back slightly so the plugs don't stick out, and to protect them a bit from any swarf etc falling on them (there's a lathe and a milling machine on top of this bench). I've lost count of the number of times I've accidentally snagged a cable and pulled a power tool off the bench. I know that I've broken a Dremel, bent a few drill bits and smashed a grinder disc doing this. I'm a reasonably careful adult. Just think of the consequences of trailing leads leading to things like kettles, coffee makers etc on top of the island if a small child was to tug on the cable, or even a dog or cat using the trailing lead as a plaything.......................

Depends. Our timber frame is cold-bridge free, using the construction method pioneered by John Larsen 30 odd years ago. So, in my case there's no "kidding" at all going on at all! A decent timber frame should have designed-in mitigation for stud cold-bridging, not primarily for heat loss reasons, but because solid timber is a pretty poor insulator and solid studs will end up being condensation loci. We used solid studs in our garage, and with 150mm of insulation between them we had lines of condensation running down the inside panelling in winter - it was so bad in places that I thought we had a leak in the roof somewhere. There's no way on earth I'd build a house like this. FWIW, I'm certain Dave has largely mitigated the stud cold bridging with the thick layer of wood fibre outside the studs, for those here keen to criticise....................

Not far off ours Dave. A 13 hour phase shift (or decrement delay) is not at all bad. For comparison, our old brick and block house (brick outer skin, 50mm EPS bead foam filled cavity, 100mm block inner skin, plus 12 to 15mm plaster) had a decrement delay of around 4 hours, and that meant that by lunchtime the inside face of the walls was getting warm, and would often get to well over 25 deg C on the South end by the end of the day. At night, these walls would then carry on radiating heat into house making the house uncomfortable to sleep in at times. Our new house is over 20 hours, IIRC, I'd need to go and dig out the analysis I did. I do know that there is no measurable temperature rise on the inside face of the external walls even on the hottest of days; the heat just doesn't get through the wall/roof before the outside temperature drops at night and heat starts flowing from somewhere in the middle of the wall/roof back out again.

Yes, as do a few other places I've since found, now. However, when the RoHS regs first came in everyone stopped selling it for a time, I found, it was buy it on ebay or live without the stuff. I think what happened was that many companies did a knee-jerk reaction to RoHS and thought it meant that they weren't allowed to sell the stuff. They then realised that it wasn't their responsibility to stop people using it, lots of people (me included!) started complaining on forums that lead-free was a PITA, and gradually the retailers started selling the stuff again, quite legally, as RoHS only applies to "products" and their manufacturers, not hobbyists. I'm not even 100% sure that someone doing DIY plumbing HAS to use lead-free solder. I've had a quick look around and I can't see anything that prevents a DIY'er from using it if they wish. Just as well, given that I used 60/40 on all our soldered pipework after the horrible experience when I tried lead-free. All the DIY sheds still seem to stock 60/40, which, I suspect, shows that there is still a fair demand for it (people like me, probably!).

And, most importantly, remember that the U value doesn't indicate how comfortable the house will be. Using a lot of low decrement delay insulation may get a decent U value, but the house thermal time constant could end up being short, and this leads to higher swings in temperature inside the house. Decrement delay is at least as important (perhaps more important) in terms of comfort, although the regs are only concerned with heat loss, not the thermal time constant. There's a good article on decrement delay here, that's worth a read: http://www.greenspec.co.uk/building-design/decrement-delay/ I can vouch for the fact that our all-timber house (no masonry) has reasonably high decrement delay insulation and a very long thermal time constant, and it makes it slow to heat up or cool down, so it tends to stay at a steady, comfortable, temperature all year around. Most importantly, there is virtually no diurnal variation. For example, the high decrement delay means that the heat from the sun takes two or three times longer to get through the insulation that it would if it were something like foam with the same U value, and in practice this means it never has long enough to get through the walls or roof during the duration of exposure to the sun even in mid-summer.

I'm certain you're right, Terry. It was a knee-jerk decision to ban lead from everything, irrespective of whether there was a significant, or even real, risk of harm in any particular application. I don't think for a minute there's any evidence to support the view that the very, very tiny bit of exposed, 40% lead, solder in a capillary pipe fitting has any health impact at all. At best a few molecules of lead salts may get dissolved in a few hundred litres of consumed water per year, which is ludicrous compared to the lead exposure we have from many natural sources. I understand why the lead ban was initiated; workers in electronics factories were being exposed to high concentrations of lead from tin/lead solder baths and manual soldering, as were workers in industrial soldering operations such as manufacturing hot water cylinders etc, but to apply the same ban on domestic water solder is both is without any evidence I can find easily, and I strongly suspect there is none.

That's pretty much what I did for our build - worked as the electricians "labourer". It worked well for both of us, as I got to make sure that absolutely everything was in exactly the right place, we had each other for company for a few days (I find working on my own, with no one to chat to, gets me down after a bit) and he got a big'ish job not long after he'd first started his own business as a self-employed electrician.

Not sure about Scotland, but here you can't even officially run cables yourself anywhere that they can't be seen for inspection by a competent person, as things like cable grouping, going through insulation and proper support of cables are all a part of the regs, so subject to inspection if you go down the DIY route. Given that there's normally a requirement to fit some form of acoustic insulation between floors and in stud walls, and given that acoustic insulation will almost always be pretty good thermal insulation, cable sizing has to take that into account for any run of cable in insulation; there's a cable size thermal insulation correction that needs to be applied depending on the length of cable within an insulation layer. In a new build it's safe to assume that pretty much all the cabling running in the floor/ceiling void will be effectively running in insulation. Our build has 200mm of acoustic insulation in the ceiling/floor void and 100mm in the stud walls, for example, so almost every cable ended up having to have the derating in the regs applied, as practically every cable in the house ended up in an insulated void somewhere.

Yes, that's the one. It just plugs into a 13A socket normally, or you could cut the plug off and wire it to a fused switched spur. I fitted a single gang 13A socket inside our island carcase, accessible via a cut-out in the back of the drawer housing (it must be accessible under the regs). This means I can just remove the top two drawers that are under the induction hob and both get at the socket and also get at the threaded ring that holds the pop-up socket in place, if I ever need to.

It's the "Simple U Value Calculator" download. There's also a simple heat loss calculator for a whole house on that same menu.

I've just uploaded the spreadsheet I mentioned earlier to our website, in the "downloads" menu at the top here: http://www.mayfly.eu/

I have a spreadsheet that will calculated multiple layers (up to 6) and has λ values for a common materials if you want a copy.

Not sure, that link took me to my empty Amazon shopping basket! The one we have is this one: https://www.tlc-direct.co.uk/Products/SE80050SS.html

To calculate U value (approximately, without corrections for surface effects) you find out the lambda value for each material layer in the wall and then convert that to the R value (thermal resistance) using the thickness of that layer and then add all the R values and take the inverse (divide them into 1) to determine the U vale of the whole wall. For example, say you have a wall like this: 15mm plasterboard and plaster skim: λ = 0.22 W/m.K 50mm service void (calculated λ using method in BS EN ISO 6946 horizontal heat flow method): λ = 0.28448 W/m.K 12mm wood board inner airtightness layer: λ = 0.15 W/m.K 300mm cellulose insulation: λ = 0.04 W/m.K 12mm Panelvent outer wood skin: λ = 0.15 W/m.K 25mm partly ventilated void (calculated λ using method in BS EN ISO 6946 horizontal heat flow method): λ = 0.14653 W/m.K * 20mm outer timber cladding: λ = 0.14 W/m.K * Converting these to R values (using thickness in metres): 15mm plasterboard and plaster skim: R = 0.22 W/m.K x 0.015m = 0.068 m²K/W 50mm service void: R = 0.28448 W/m.K x 0.05m = 0.176 m²K/W 12mm wood board inner airtightness layer: R = 0.15 W/m.K x 0.012m = 0.08 m²K/W 300mm cellulose insulation: R = 0.04 W/m.K x 0.3m = 7.5 m²K/W 12mm Panelvent outer wood skin: R = 0.15 W/m.K x 0.012m = 0.1 m²K/W Sum of all the above R values = 7.924 m²K/W Take the inverse to get the U value: 1 / 7.924 m²K/W = 0.1262 W/m².K * Note that the outer void and cladding improve the U value by reducing wind washing heat loss and by changing the surface loss, so although not included in this simplified calculation method, the true U value for the wall will be lower as a consequence of this.

Same here. Our basic sockets and USB power Sensio pop up is very solid-feeling, and has the advantage that you can put it down with things plugged in and the leads just come out of the little spring loaded flap, making it far neater than sockets on the side of the island with trailing leads that would inevitable end up being caught on something as someone walked by.