Dreadnaught

This (in green) is the sort of thing I had in mind. All WCs on main runs. Stick a rodding eye at the end of the long run if it exceeds the max length of a run according to BC. You don't need to angle your runs at 45º. You can approach the IC at 90º and have a short bend right next to the IC to hit the socket (bends are allowed so long as they are right next to the IC). And note that, while bends are best avoided in general, bends of <30º are generally allowed away from the IC in long runs if they are required.

Interesting. I am unsure about having the WCs on branches. I would be tempted to find a way to have them on the main runs. Perhaps have two main runs branching from the purple IC. Just an idea. My only definite comment is that you could consider just a rodding eye at the end of the run rather than a full IC if you wanted. (I am not an expert but I did design (and install) my own drainage system for my current build, which has been signed off and inspected by building control.)

sadly I don't think you will find one. Sufficient to say that it is a kiosk made from a palette-as-a-base with flimsy OSB walls, door and roof. Despite it being plumbed in to the sewer, having a fetching window with a view (no glass), and a bucket conveniently filled with water for flushing, the consensus from certain visitors thus far has not been complimentary.

Heat loss through frames is often greater than through the glass. Manufacturers who make triple-glazed windows probably care more about frames than those that only make double-glazed ones. Buy good frames.

@Visti has a Brink model I believe. I heard he was happy with it. Remember that the Brink units are also branded as Ubiflux Vigor too.

(@Nick Laslett, I might have about 8m of the 32mm insulated twin pipe spare on my site if you're interested. I'll measure the off-cut next time I'm there.)

What does that mean please?

Same here. I just sent them the whole report.

Suspect that's a minimum. Or rather a maximum that their lifetime-aging-system will allow them to estimate. 30-years will see me out. And it will probably be an easy-ish job to replace it when the times comes.

I too am considering using Ubbiflex B3 for covering my insulation at the bottom. I have the samples of grey and black (tempted by the black). I am puzzling over fixings. @ToughButterCup, how did you attach yours to your EPS? Regarding stopping vermin, I am thinking of putting a narrow layer of MOT-style stone right next to the house and up against the Ubbiflex. I assume the buggers won't chew or burrow through stone. Then backfill with soil for my flower beds.

I paid £22 per panel delivered, with free clips. Cambridge.

@GaryM, looks great! Installed by IdealCombi's official installers or DIY?

I have a simple DIY OSB cubicle on site sitting on a couple of pallets, knocked-up by one of my groundworkers, with white goods and a flexi to the nearest IC. Bucket for flushing. But I also have access to proper facilities next to the site.

I have my SAP calculation for my forthcoming bungalow and all generally looks good. The roof and floor have U-values of 0.08 W/m².k. However, the walls are a bit low, about 0.18 W/m².k. I did this on-purpose to maximise floor-space but it has turned-out a bit lower than I expected so I am thinking of adding an additional layer of insulation inside the the airtightness layer of say 25mm or 50mm of PIR. I was planning a 25mm service void anyhow. My questions: Could I just fill that service void with sheet PIR everywhere except where services run? That would do the job without stealing more floor area. I am aware that electrical cables may need de-rating if they are insulated. To counter this, could I just leave, say, 50mm air-gap each side of a cable run? Are there any other problems with largely doing-away with a service void by filling it with insulation? (For service runs, as a bungalow with a warm roof I will have 200mm of open space between the metal-web joists in the flat roof). (The external walls will be 240mm I-beams at 600m centres full-filled with blown-cellulose/Warmcel.) (The airtightness layer is Pro-Passiv Smartply.) (I am aware of condensation-risk analysis and I am confident that adding such a small amount of extra insulation won't cause a problem).

Keep in mind that I am building this dwelling primarily for my enjoyment of the process and journey, and as a learning experience. I am therefore optimising for my own involvement, which is close to full-time, not for the usual triad of price, time and quality (although from that triad, I choose price and quality over time). I'm sightly reluctant to name names on this public forum as it may be unfair to those I did not choose. I would be happy to send you a PM with the names. In general terms, my long list was about eight frame-companies. I visited the factories of two and spoke at length with about four. Unusually, I was quite opinionated about the frame build-up that I wanted and so was looking for that flexibility. In the end I chose the company that offered that flexibility and which also happened to be a local company, not halfway across the country. I learnt, with the benefit of hindsight, that it is perfectly possible to take a different approach. Having now also been introduced to an excellent and personable frame designer, next time I might start with them and ask them to recommend a frame-manufacturer in the local area of my next build, wherever in the country that may be (frame manufacturers are the clients of frame designers). I learnt that it is perfectly possible to work with the various parts of the supply chain oneself, such as pile designer, foundation designer, frame designer, roof designer and make it all work, and not resort to using a one-stop shop, with the inevitable constraints that provides. I didn't choose a standard package but invented my own. Its a bungalow: Foundations: a complicated and completely bespoke solution. Screw piles, 240mm heave protection, 230mm PIR insulation (not the more usual EPS), reinforced concrete raft (with UFH pipes and lots of other pipes and ducts embedded within it, including the potable-water distribution pipes). Three embedded recesses in the concrete (two shower-formers and a mat-well for the front door). Frame: 240mm I-beams full-filled with woodfibre insulation (either Wamrcel or woodfibre batts, I am still choosing). No internal walls: I will do those myself in metal framing. A single steel beam. Flat green roof: warm roof, by Bauder for the transferrable warranty and no worries about leaks. Bauder is also installing the extensive green-roof atop. Six windows. Nine roof windows. Passive-house-style front door (the only external door). I chose this as I had read a lot about frames and wanted my chosen balance between thickness (which steals floor space), U-value, decrement delay, acoustic insulation, and greenery (saving the planet). I will be interested to see how this frame preforms. Yes, two of the big national firms did. But that was actually of no interest to me as I want to do the airtightness process myself anyhow to see what sort of results I could achieve. – (By the way, I simply could not have done this without BuildHub!) Hope that's helpful. Of course, it is only one personal view and, as you may have gathered, I am somewhat unusual in my motivations for building. Others, and there are many here who have much greater experience than I, may be able to provide insights that align more closely to your own personal circumstances.

When is an Intumescent Pipe Collar needed?

How would I seal the outer face? Foam around and then just tape the duct to the breather membrane?

Could someone explain how to make an airtight seal for the supply and extract ducts to atmosphere please? The ductwork work will be 160mm Aerfoam insulated mass flow ductwork. My external wall will be a timber I-beam wall at 600mm centres. Cladding will be brick slips. Is it simply a matter of cutting the holes through, inserting the pipes and then using a pair of airtightness grommets on the inside airtightness layer?

On the subject of silencers, I notice the Ubbink Air Excellence 800-series manifold box has the option of putting sound attenuation foam within the manifold itself. It is shown in this video. And it seems you can buy extra attenuation foam pieces too to bump it up yet further, although I am not sure about this. Could such a manifold also act as a silencer too I wonder? Two birds with one stone.

Ask away. My frame is in the very final stages of specification and is due to go in to production very soon and will be erected on site hopefully the other side of Easter. Having chosen my frame company more than a year ago, I remain very pleased with my choice. They are a friendly relatively local company and it has thus far been a joy to work with them. They also introduced me to a splendid frame designer and it has also been a pleasure to work with him, albeit lockdown slowed him down as it has for many people with families.

I read your reply with care. Really interesting and highly relevant. Thank you very much. Regarding doubling ducts, what about pressure as well as noise from turbulence from within the pipes. For all longer runs, wouldn't doubling ducts also reduce pressure, which in turn would reduce how hard the fans need to work, which I turn could would reduce noise from the appliance itself. Any merit in such reasoning too? And given that ducting is not a big cost in the overall costs, suggest doubling long runs as a matter of course? Oh yes, I forgot about that document. Thanks for the reminder.

Thanks @Iceverge. When you say 90mm is that the external dimension? And internal would be 75mm? Is that right? 2.5 m/s noted, thanks. I am thinking of using Ubbink Air Excellent System, which 90/75 duct and even higher capacity one that is semi-rectangular in various sizes. Ubbink has good data on their website for each component showing volumes, flow rates and pressures, which are very hopeful. I have calculated my room sizes on-the-back-of-an-envelope, which has been helpful in deciding on duct numbers and sizes. For example, I have quite a large living room and was thinking of putting two supply outlets, each with two 90mm ducts attached. Four ducts in total. Running the numbers showed that a single 90mm duct to each of the two outlets would be fine but, conversely, one single outlet with two ducts attached would have been border-line noisy.

Do I actually need someone like BPC to design my MVHR ducting system? For my new-build bungalow, it seems really simple. I have designed the ducting plan myself following the basic rules: equal number of supply and extracts across the house (5x of each) double pipes to every terminal so it is quiet supply to bedrooms and living room (x3 & x2) extract from bathrooms, kitchen, utility room and plant room (x2, x1, x1, x1) room terminals as far from the door as possible Seems simple! What am I missing? Is a pro-design for the air-change data, which is needed for building control? The reason I am thinking about this now is that I am just about to put the timber-frame in to production. The frame has one single structural steel. And that steel would benefit from some pre-cut holes (x6) to allow the 75mm MVHR ducting to pass through it. I can cut the holes based on my design. Or should I get a professional involved?

Welcome @Phaedrus! There's a few us around East Anglia self-building. I'm in Cambridge and @Nick Laslett is in Suffolk as two examples.

Resurrecting this old thread. The MVHR extract vents in my kitchen either need to go though a steel beam or can be a linear diffuser in a wall without needing cut a hole in the beam. But I am still not sure whether linear diffusers are good as extract terminals. I wonder, has anybody used a linear diffuser in their MCHR system? @MikeSharp01, did you use one in the end?