Nickfromwales

Sorry, but not my experience directly. Simply what I saw, heard and witnessed directly whilst on a clients build. The issues with Velox run way further, and the builders who were tasked with this build were some of the most skilled and competent builders and joiners I've had the pleasure of working with for quite some time. They were constantly suffering with, and engineering solutions to the problems with that product / system. Even boards braced down to as little as 400 OC were breaking and blowing out. Maybe OK for someone building with it time after time, but a one-off would be an expensive baptism....

No need to go crazy. Assuming you have a 110m AAV or an SVP for the rising foul stack, the 2 anti-vac basin traps will be all you need here. The horizontal breaks in the run, coupled with the 50mm pipe, will be all the air break you'll need. Trust me, I'm a pipe doctor

They're a way off for availability atm anyways.

23.5 total on 1ph! You were lucky there me thinks

A combi cannot deliver heating and hot water at the same time. It has an internal diverter which chooses either one. DHW ( domestic hot water ) takes priority, so if you turn the heating on at 07:00 and get up, and 3 people take a 10 min shower each, the heating will be off, and the house remain cold, for that 30 plus minute period. As you'll already be inside the 'insulated envelope', you wont need the insulation on the 1st floor, quite the opposite. A product with largely bogus claims. Every mass builder would be going for this if it was any good. Pile of crap i'm afraid.

OK, obviously my advice is for when you go for the service alteration, assuming you then wouldn't want both. TBH if you use the old hoover technique and some fishing line you can suck yourself a new draw wire in with ease.

Not quite, more a statement of compliance as at that stage you'll be non MCS ( so no export payment eligibility ) and setting the hybrid inverter / declaring ZERO export At the most the DNO will ask a representative to attend and witness the zero export limitation in practice and sign you off. What you do after that will be of ( ahem ) zero interest to them. You could have 50kWp of solar and 50kWh of battery, they would not care one jot as it would all be on the D/C side.

No need to. Done plenty as you indicate, more than I can count. That's fine. You need to use 50mm waste pipe for everything from stack to bath, and then 50mm from bath to the rising bend at the image above. Reduced on the vertical output of that bend ( not elbow ) with a 50x32mm reducer. You will deffo need to fit either a 50mm AAV under the bath ( if you've got a removable bath panel ), or take the 32mm waste pipe up from the 50mmx32mm bend to a 32mm AAV to an above attic / eave space(?), or at the very minimum put anti-vacuum tras on both basins in both rooms meeting that run of 50mm pipe.

Will deffo need a sizeable buffer tank too, so when DHW is being drawn for extended periods of time ( drawing a bath / showering back to back in the mornings ) the UFH has a reserve to draw from. That would be a minimum of 150L, but bigger would be better say 200L. Remember that a combi cannot deliver heating whilst producing DHW

Yup, hence my suggestion of hybrid and D/C for the new additions. Needs no begging / going on bended knee. One less A/C to D/C to A/C conversion also, so more efficient charging the D/C batteries from the D/C from the roof.

If you look on the Cylinders2go website ( I get all of mine there through Trevor, as have many others on here ) there are all of the sizes and dimensions. Remember to look at HP UVC's not regular ( gas / direct electric ) units as the coils and sizes are different vs capacities. You get the purge cycles with most HP controllers, however on a sealed system in this day and age, most consider it to be unnecessary.

Besides Velox, it's the system I've seen / heard of the most blow-outs during the pour or deformities after the pour. Anyone considering Velox should beware that they will try to supply 20% more than you need. Then leave you with an expensive pile of various blocks worth less than the skips to take them away which they will refuse to refund / recognise as superfluous.

No, it wouldn't. A trap does what it says, traps water. Zero water will remain in the above images, and the only 'trap' will be whichever you decide to go under the sink ( S / P / Bottle etc ). I'll never get tired of 6' blondes Basins are typically ~820-830 from FFL so that's the height of discharging pipework. Some go horizontally to a soil stack, others outdoors to a snow box, some under DPM level to a drain gulley and so on. What happens after your "90o bend"?

I have done many bathrooms with the shower screens bonded with the clear CT1 and never had any issues with discolouration. All very much on show so I'd have been pulled over it by now. The white does discolour, and should never be the finish left on show. Around the backs of WC pans etc I use the clear CT1 for fundamental sealant, wiped back slightly with baby wipes to leave a gap for a microban / forever white silicone sealant to go atop. When that gets a bit funky, it is very easy to strip and refresh.

I would have neither, and go underslung?

Hi. What you need to do, sir, is take the rest of the day off and plug yourself into the BH search engine. Delete everything you think you know, or what you've heard elsewhere, and go dig up the wealth of gold-standard information that resides here. Don't be afraid of blowing the dust off topics and adding new questions, as that is the best way of keeping our library here in good order I've installed many ( for clients ) which ( subject to them not buying cheap 'Chinese' units ) have been whisper quiet or completely inaudible. MVHR does not move / control heat, that would be HVAC or forced air systems with huge ducts and monster air flow rates

Exceptional attention to detail from the timber frame producers and erectors. Not seen work as neat and presentable as that for quite some time. Love the red front door, what a great signature Have you applied to the DNO for capacity of A/C coupled batteries as well as that whopper of an array? The A/C capacities ( PV and intended battery ) combined seem high for a 1ph installation? Tres bien.

Dragons Den moment there 🙄

You must have lots of gold medals for swimming?

You do like life on the edge....... Still got all 10 here, but I am very sure that's down to luck with what I've got up to over the years

Oh, and get rid of the full height noggins! Replace with ones 25-50mm lower, ventilating at the top and bottom of the runs. I bought metal racking which came with MDF shelves ( crappy 9mm POS ) but they have been the only thing to harbour moisture and grow mould. The OSB3 shows zero signs of this, so will be what I replace these crappy shelves with.

You measure, I'll cut

Err, nope! A trap is formed when the pipe rises again, after the basin has discharged, 'trapping' water eg blocking the pipe. Yours both show continuous falls so are fine, however option 1 would be the quietest method. You hear much more nose / sound from water changing direction and from significant drops before the invert. FYI I have started wrapping soil and waste pipes with Kilmat / other sound deadening mat as a solution to banning the higher frequency noise, plus as much acoustic rockwool insulation as is practicable for the lower. It is imperative that the pipe runs do NOT contact the metal frame as that will be like an amplifier.

An interesting comparison to what others have said, but a very relevant consideration if maxing out on grid-tied PV. The OP may be in a better position due to the split arrays producing steadier all-day-long output vs a huge south facing array peaking at midday.

Ironically, it could make you worse off, due to being closer to the grid max voltages for the inverters to shut down at ( 253v ).