TerryE

One other thing, and it's a personal view: we chose a frame+slab bundle tailored to our custom design from a specialist manufacturer that targets the passive-class market. I know of example builds where the scope of supply is stripped down and therefore a lot less. But you have to compare like-for-like. In our case we had three major subs: the slab and frame; the ground works and exterior, done by a local builder; and the windows . All of the other trades we either did ourselves or used the builder's subbies. The net result is a cosy warm house that looks really nice, costs bugger-all to maintain or to run -- for roughly the same price as a run-of- the-mill one-off development.

PM + Architect + QS between them can add over 20% to a self-build. A self-build is invariably a one-off so will cost more than a like-for-like mass-built estate house, simply because the developer can amortise a lot of costs over N builds. This being said, with a self-build you and your partner have the opportunity to take on activities (if you can spare the time) that you might otherwise be paying £250-500 per day for. In our case, I've done a lot of PM in the IT world before I retired early; I also have a good 3D visualisation sense, and we wanted a fairly standard house in terms of layout, though passive-class in performance. So between Jan and I, we've done all of the design, PM, bureaucracy, and a lot of the internal trades, such as the carpentry, plumbing, etc. The end result is that we've probably saved ourselves maybe £60-80K on the cost of our build. There's a lot of other members here that have done likewise. Moreover, I suspect that there are less than a 100 commercially-build houses with comparable energy specification to ours coming on the market in UK annually. It's a long road and can be very stressful, but the payback can also be huge. And there are people here willing to help you on the journey .

Maybe, but the general tone detracts from the underlying points. If you upset people, then they tend to stop listening, and if they don't listen, then they won't learn and this kind of defeats the point of the debate.

Gotcha!!! Not paying attention! http://www.tonyshouse.readinguk.org/tony.htm Not sure Tony invented it, because this sort of wrap is pretty standard on timber constructions, though most block-built houses are just allowed to leak from what I see

Ask your Brown Owl.

AND its got a schrader valve included. My hero!

Thanks guys. The end stop idea seems to be simpler to do than trying to make a T. I'll give it a go tomorrow.

I am trying to work out the easiest way to procure / fix a Schrader valve to the kit. My current thinking is to buy / butcher a bike tyre and lots of CT1 and wipping onto a piece of 15 pipe. Any better suggestions?

Jan's gone all coy -- mainly because she's got her head in a book, but her aside was "but I did the plumbing, so I'll rest easier once I've seen it pressure tested!"

Clive, thanks for the kind offer, but I am going to need this on and off (forgive the pun) over the next month or so, so it would probably be simpler to borrow the design and do my own. For others' benefit, can you give a quick parts list.

My sink is in the kitchen centrally against an outside wall under a window. I've got 2×Hep2O 15mm coming down the wall to the right of the window with 2×15 mm copper running along behind the units, each with a slow bend into the unit under sink. I've simple cut a slot hole in the plasterboard to bring the Hep2O pipe out clear of the wall behind the corner unit and I've 2 × Hep2O 90° elbows joining the copper to the Hep2O and turning the 90° at the same time. I would have used end-feed copper 90s and done a straight Hep2O to copper, but Jan's argument was: what's the difference between a copper - Hep2O straight vs. elbow. I couldn't come up with a valid counter-argument, so I lost this debate. I'll leave you two to discuss this while I go and hide

OK, another go around the merry-go-round on this one. Where we live is flat and the mains is pumped to around 3 bar IIRC. I have one particular pair of elbows that are behind a corner cupboard in our kitchen and the new worktop is going in on the 30th, so I want to pressure test these to at least 5 bar before then, because if either fails after the worktop is in then it's going to be a total PITA. As far as I can see, the Rothenburger RP 30s are the standard entry piece of kit for doing this, but they cost about £140-180 new. Has anyone used any of the cheap Chinese clones that you can pick up for down to £40? OK, I accept that the main risk is that the gauge is crap and I end up over-pressuring the system, but I thought that the simplest way of preventing this is to add a second pressure gauge at £15 or so. Any comments or suggestions? @Nickfromwales @Onoff or anyone got pearls of wisdom?

I left some 75mm wide sycamore saplings on my boundary when clearing it just over thirty year ago. About 5 years ago I had the last one felled and the root ground out. It was about 400mm wide by then and the root ball was even bigger!

Yup,Tony also mentioned the alternative of using hangers plus sealant, but be aware that you can get air leaks particularly in the risers between blocks if not fully filled; that's why the render suggestion is made. Alternatively is you haven't hung the joists just hang a strip of air tightness membrane around the wall at floor void level and punch the hangers through it and seal each one.

To be honest, I not the expert here. I was just relating of detailed conversations with a couple of crews who worked on my timberframe house (both of which had a lot of experience of erecting passive house class both blockwork and timberframe constructions, and these crews essentially gave the same message that Tony described in his blog here, and this was that trying to achieve airtightness in the floor void zone was a real PITA if you didn't do something to actively address this (such as the sock method that Tony used). Whether you sit your joists in the block skin or use hangers the material interface invariably causes separation of the mortar at opens many cracks through the blockwork. These are structurally insignificant, but can really impact the overall airtightness. Essentially the house will leak like a sieve. As JSH once mentioned, if either of our houses was totally airtight except a 1" diameter hole somewhere, then it would fail a 0.6 ACH airtightness test. Just out of interest, here is how they did it on our TF build: the floor was decked out to the external perimeter and the airtighness membrane looped back onto it before the next storey cassettes where craned into position. I am not saying that everyone wants or needs to achieve an 0.6 ACH figure, but more that some though about how you seal the internal floor void surface of the exterior walls will have a major impact on the actual airtightness achieved.

@hmpmarketing, this also has the advantage that the neighbour did this from the planners PoV so its outside your control Check with your BInsp that the neighbour has offered to remove the tree and grind out the stump and see if he will give you a concession on this in this light.

@tonyshouse is one guy that posts here and been through this though there maybe others. If you want high levels of airtightness with a block wall then you are going to have to use the inner face of the blockwork as the VCL / airtightness layer. It is very easy in the laying of blockwork to leave or to create fine air paths between blocks. A direct inner render coat or plaster coat will help to minimise these, but the danger zones are the floor voids and joist hangers which tend to be omitted when planning plastering, as well as the window, door and services openings discussed in previous posts. The best time to address airtightness in the floor voids is during construction, but you are now past this, so the next best time is before boarding out. If you don't bother then at best you will get very modest airtightness by sealing around skirting, etc.

Have you not just thought about finding out what a reasonable cost of the extra foundation work is, knock off the price of felling it and grinding out the root ball and offering your neighbour that as a lump sum plus you carrying the cost of removal for his agreement to let you remove it? There's nothing like a bit a cash to encourage cooperation.

Ouch! I can see why the BInsp would cry foul on this one. You need to be careful with trees so close the foundations.

As I said, I can't fault the kit itself, but I suspect that a lot of the issue avoidance is down to the competence of the kitchen designer. We were impressed with ours. We didn't have a single issue with the Bill of Materials, though we did need to order the extra pelmet/capiital to get around this extra 70 mm issue. But again Wickes supplied this free in a two-day turn around.

This is the one gotcha in the wings. The Slabtech FAQ also mentions a minimum 120mm behind gas hobs, however this doesn't square with examples in the Wickes showroom where a ~500mm deep gas hob is in a ~600mm work surface -- that is with 50mm front and back. We will have a heat resistant glass splashback that's rated up to 400°C. I don't think scorching is going to be a material risk in our case as we'll generally be using the induction hob for an longer duration cooking. The gas hob will tend to be used for cooking that needs fine and rapid heat control, e.g. making sauces, scrambled eggs, etc. But the Sheridan guys are coming to template the worktop tomorrow PM, so we can discuss this all with them then. BTW, the steel 30×30 angle worked fine. I used steel rather than Alu because of availability / lead times.

@SteamyTea mentioned the SHC of Cellulosic filler, what he's talking about is the specific heat coefficient, also loosely referred to as the thermal mass. The ratio of the SHC to U-value has the dimension of time and drives what is called the decrement delay factor which is the lag it takes for external temperature variation to transmit through the wall fabric. This profile gives a DDF of days, which means that you can ignore diurnal variations in your heat calculations. IMO this is more useful that the nominal extra 0.1kWh that you lose from the drop in U-value. Especially as the main issue that you will face in a room of this size is not so much keeping it warm, but controlling excess heat and how to divert or dump it. Big rooms usually have big windows and you can easily see solar gains of ½kW / m² on windows which can play havoc with your temperature control if you haven't designed to accommodate this.

+1 on service cavity and cellulosic filler. You can also get a special airtight version of OSB that has a plasticised film on one surface and is designed for use as air tightness barrier. Also the is some advantage in using a breathable outer layer such as Panelvent cover by a tenting fabric. Consider using Foamglass as a thermal isolation layer. You will also need the whole thing signed off by a decent SE.

Can I raise a dissenting POV? Surely there are two different answers here: What's the best way if you are a professional and need to do this on a routine basis? What's the best way if you are a self builder and only doing it once? In the first case, you really need a tool which is accurate and quick; no doubt about that. In the second case you only need to be accurate, but is it really worth spending an extra £100 or so to save yourself an hour's fiddling around getting it right? I think not, but then again I am not cash rich at the moment. Though if you haven't any accurate laser level, then ~ £100 seems a reasonable price. What you need at a minimum is a way of establishing a set of datums, one per room that establish a common level throughout the house, and preferably each near the door connecting to the common hall / access. There are loads of ways to do this. The water level works really well (I did a blog post about this). So does a Dumpy if you have one, or any kind of calibrated laser level. If you are using levels then IMO it is important to chain from room to room at the doorways. If you want to double check then back chain from the extreme back to your primary reference. This will throw any systematic errors in your level. Do this a fixed amount above FFL and mark each datum well so they don't get lost in subsequent building works (e.g. screw or bond a bit of wood to the wall and cut a notch in it and mark it with a sharpie.) Then if you do need to redo any room you only need to measure down the fixed amount from the datum to reset the level in that room and you can be confident that it will still be correct. And then you need to establish reference levels around each room, and here pretty much any type of calibrated laser level will do the job. The expensive ones will only save you 10 mins extra setup per room. And I wouldn't worry too much about a few mm systematic error across the chain, because if you think that the builders or you will end up laying the FFL exactly to that level then you are mistaken. Even if they use a decent self levelling cement to finish off each room, do you think that they are going to use the exact amount of cement to hit the level? They make it up, pour it in and give it a float and leave it to find its level, and if they are good then you'll still end up using the door thresh or carpet bar to hide the hopefully few mm offset between rooms. In my current house some of our "level" floor slabs are about 1cm out across the room.