Dreadnaught

Out of interest, why was it perforated duct? I assumed those were used only for drainage solutions.

Yes, make sure you can gat the CAD files and that the architect is OK about the IP (they should be). Regarding IP, the principle I have encountered is that it is OK to use the design from your architect for the purpose intended without their further involvement (i.e. building that house in that location). Its not OK to then sell it on as a generic solution to others. That would breach the architect's IP rights. Getting the CAD electronic files can be trickier. I have them for my build. Added: I agree with @Sensus. Ensure your agreement with the architect entitles you to receive the CAD files. Some architects may baulk at this, in which case move on.

@Oldsteel I tried an attenuation tank as an option but I could not bury it on my site (no dig restrictions), it would have been sitting on the surface. It was rejected as a solution by the council SUDS-person as being a potentially temporary structure. I imagine the your tank will be buried and thus will be an undoubtedly permanent solution and so cannot not fall foul of such an objection.

Sorry I can't help with a specific contractor recommendation for you, @Visti. My impression was that any drywall contractor could do it but that they will inevitably grumble. I have heard of some bodge jobs so, like you, I'd be certainly be looking for someone who'd had some experience with it. Generally. I am interested in your decision, I am seriously considering Fermacell myself, because of the lack of the need for any plastering, but in my case I am tempted to try and DIY it as I have the time.

Good point. It is not an adopted road, indeed it not owned by anyone, but it it is open to the public, although I shall be the only regular car driver across it as just beyond my entrance there is gate blocking the road which I have never seen opened.

Thanks everyone! Superbly helpful. Here's the new plan based on all your comments. Got it down to just 3x ICs (from 8x in the plan by the engineer). What does everyone think? Is it OK to have the ICs just outside my gate? Nobody owns the road. Would help to keep the IC's off my paving. The road is concrete. The gutters (shown as red dotted) are long, about 15m each. Is that OK with a single downpipe serving both gutters. I tried a few online calculators and think it is but not sure. Roof is 142 m². The foul run is 12m to the IC and then about 12m to the bathroom, so the max allowable. The rainwater run is about 24m, which seems OK as Part H says 45m max from rodding eye to IC (!). In the road, the storm main drain is alarmingly deep, 2.2m. The foul main drain is just 1.2m deep. Think I will need a trench box. Then I just have to convince the engineer to change his design and tree people to let me (hand-) dig nearer the chestnut tree. D. (IC = inspection chamber. Part H = building regs.)

Yes, thank you @Bitpipe. My engineer initially specified four ICs for the foul drains and yet another four ICs for the rainwater drains, eight in total. With the advice from BuildHubers, I hope now to get that down to just two ICs for each, four in total, saving quite a lot of money and effort.

Oh I would like to see the BuildHub version of it. I wonder if it includes pregnancy too.

Thanks @MikeSharp01. That's my main open question for me now. Whether I can run the drainage pipes x2 (foul and rainwater) into a single service trench with water, gas, telecoms and electricity or whether there is some fundamental reason why I shouldn't do that. Anyone know?

Thanks @MikeSharp01. Did you also have drains in your trench? If so, how did you position them?

This seems to be the standard cross section of a services trench. For my build, I am thinking of having a single combined services trench bringing absolutely everything into my utility room so I am wondering how to to fit everything in: Why the 350 mm radius gap between the water pipe and the gas pipe? And why the separation between the other pipes? Where do drain pipes go (foul and rainwater)? Could they go in the gap underneath the gas/telecom/electric pipes/conduits? My falls would mean that they could well fit there nicely.

@PeterW, in your scheme, how would one rod a blockage between the utility room and kitchen?

Thanks @PeterW. I like your simple approach but the council tree officer might not approve it because of the root-protection zone for the chestnut tree on the south boundary, shown with a green dotted line.

Thanks @scottishjohn. Yes I believe it is 22m according to Part H. I think it is because rodding points are only for pipe terminations. An IC is needed for a corner > 30º. Any other votes?

My SE initially specified a hydrobrake and, when I looked it up, I was surprised at how much it cost (around £1,000 if I recall correctly). In the end I agreed with my SE to submit the drainage calculations to the council without the hydrobrake on the off chance they would approve them without it and fortunately they did. However, following our heroic SUDS efforts, the calculated maximum run-off rates were not hugely in excess of the mandated figure which is presumably why.

Hi guys, which of these two foul drain run designs is better, 1 (red) or 2 (blue) and why?

Many congratulations @Thorfun. And welcome to Buildhub!

@Triassic by coincidence today I was researching brick slips while await my planning permission. I will need to cut some brick slips for the specials that will bridge to an angled wall I will have in my design. In doing so, I stumbled upon an entire world of brick cutters, cutting bricks not just slips. To my surprise there seems to multiple such companies in each county. Here is just one example fairly near me in East Anglia to give you an idea: http://www.masterlaybrick.com. They can make slips from any brick you choose. As an aside, I have learnt there are two types of brick slip tiles: (1) those made by cutting bricks; and (2) those made by extrusion. Type 1 creates rather more waste in the production process so, to my eye, Type 2 seems better.

Roger Scruton (misquoted): in Britain everything is permitted unless it is forbidden; in Switzerland everything is forbidden unless it is permitted; in France everything is permitted, even if it is forbidden; and in Russia everything is forbidden, even if it is permitted.

Under pressure, I believe that eBay is tightening requirements for its sellers with regard to VAT. If the seller is UK based, I wonder if approaching eBay might be another avenue.

We have them in my current place (albeit 10-years old models). Audible noise from the motor; prone to dumping cold water on your head after the shower is paused and restarted; all-in-all pointless. But they do have a flashing LED. Of the three we have, one has needed servicing.

@lizzie did. Have the name of her designer if you'd like it. I suspect that she won't mind me sending it on.

Welcome @ianfish!

Welcome @Davidkw. A couple of places to start: https://www.gov.uk/vat-building-new-home , https://www.gov.uk/vat-building-new-home/eligibility, https://www.gov.uk/vat-building-new-home/how-to-claim. We also have a large and well-maintained thread on the forum here about the VAT reclaim process but I believe that you need a few more posts (to be an established member) before you can have access to that. @newhome in particular is very knowledgeable on the subject. And @JSHarris has a sample claim spreadsheet that he has provided to some others here. Some members, including @jack, are following current cases about exactly what triggers the 3-month clock on claiming after the completion of a build. And there are some companies various members have used to assist in the process (for a fee). @joe90 has used one recently for example.