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I'd never read up on this so has been interesting. One of the sellers had good info on use class. Light domestic, light office, heavy commercial, including how much water it could hold! 6 litres/m2 is a lot. Thicknesses not so easy. It's potentially tricky and messy to retrofit so needs thinking through.

This may or may not be what was meant, but in out last house (block) we had a room with a vaulted ceiling put over the garage, work commitments meant it was done for us and in our naivety we went with the pir insulation recommended, which is effectively a huge component of the sip. The "feel" of that room was totally different.....dead/flat/echoy...just not "good". Sufficiently unpleasant to make us push back on the architect and move away from pir (in our case to rockwooĺ) for our stick build. Not yet plastered (hopefully only days away🤞) buy absolutely no regrets, even as it is now (osb/ply lined) the "feel" and noise absorbance are totally different.

I had thought they were all of this type (push air to the sides as it leaves and follows the ceiling). Just did a search for those that advertise as ‘coanda effect vents’ - £100 per vent!?! https://www.epicair.co.uk/products/air-diffusers-gypsum-performance-circle?variant=48789368701213 @JohnMo all points received - I’ll add some extra columns to my spreadsheet where I’m pulling all this together 😁🙏🏻.

We are always interested on here. Sometimes driven by pure schadenfreude but mostly because we know we will go, or have already been, there.

Lots of questions The basics and that's where you start from. First it's about pressure drop management, a higher pressure drop the fan in the MVHR have to work harder to give a set air flow. Second when you use a plenum and individual pipes to rooms, the strings in parallel, so you will have one single run which sets the pressure drop - it's generally the longest pipe run and the highest flow rate. This is the route you need to concentrate on and get low. Then make sure all other routes do not exceed that pressure drop. Noise comes from two sources A. Fan noise - as mentioned above B. Duct noise from air velocity. This is generally managed by looking after pressure drops. So get your data sheets, look at pressure drops for ducts, bends and terminals. Get data sheet for fan speed/pressure charts for the MVHR. Before you do that you need to understand each terminal flow rates. You can massively reduce duct length by using coanda terminals. These will throw air from one side of the room to the other following the ceiling before coming down.

You’ve seen pics of new born chicks. Bald, scrawny and terribly wrinkly. So in at least three aspects I do resemble one.

Maybe I'm naive, but of the endless choices I need to make in this project, I hadn't given the specific type of insulation a great deal of thought. I currently live in an old cottage so if I'm sat in 15 degrees now, I'll be lucky (storage heaters and log burner). Unsure what you mean by permanency? I didn't expect you'd see any difference once the building is finished, whether blocks, timber frame etc. Clad on outside and boarded and plastered inside. I have a friend who is a well respected local builder - they chose a SIP construction for his son's house. No complaints with the method, construction etc. They will be a reasonably affluent family and, as builders, could have built it in any way they chose - subject to meeting the look required by the planners in the parks. I hadn't considered the concrete filled blocks, no. The extension stands as a separate building, joined by a short glazed corridor. The planners wanted clear separation of the new and old. It will be a shared airspace but two distinct spaces. The long game is to build a house to live in, it's at my place of work, has a huge workshop behind, 1 hectare site. Be happy living here 'forever' or until too old and knackered to look after the place. I have two young boys and with housing costs, I want them to have lots of space - it's madness building a 3 year old (5 if build competed on target) a room with an en-suit - but if housing prices continue as they are, they might be at home for a while. The boys rooms, in the extension, mean they can have some freedom/privacy as they get older, and blast some music without it affecting me so much. The stone building is well-built but will be completely insulated, and hopefully airtight to modern standards. Some large areas of glazing will increase heat losses, but they are a lot of the character of the building (two large arched doors where trains drove through the shed).

No, Don't pay them and find someone who actually understands it to do the job instead.

Another proud BH moment, just magical when another of its young finally fly's the nest. This is what happens when flapping turns into flight. Godspeed........and may you have many more successful plumbing adventures along the way. Until tiling, and the flapping starts again ffs

I think this is grounds for a new super-thread, to take us into 2030 mate. Get your pencil sharpener out and lets do this shit.

Rushed to screwfix after finishing on site. Stumbled in through the doors, brandishing my phone with my “Good news, your order is ready” text like it was my bow of burning gold. I grabbed my stuff, ignoring the sad “oh look, another weirdo” looks and raced home a fast as Skooby can manage nowadays, so at least there’s no risk to the licence. Connected up the shower valve to the pressure tester via the ‘panacea connector’ and…….. watched the needle steadily drop. Oh. But wait! I’ve been here before. So I tested the tester. Duff. Ah. So whilst I can report that the connectors fit beautifully both the shower valve's and the tap connector’s compression thread, I can’t yet pressure test it. I think I can fix my tester tomorrow, or if not I’ll buy another, so I’ll report back then. Again. Assuming anyone’s interested. And if you are then just like me, you really should get out more lol

Final answer 🤣 32 > 40mm for the basin as it is more than 1.7m Boiler / bath waste 40 > 50mm and downstream of the basin Inspection bend at rear of WC My 'stub stack' idea is no good, branch would be too high above invert of stack.

Ok, so I'm revisiting some of my MVHR design and I've found myself circling the following questions, without really finding the answers from any of the manufacturers sites (happy to be pointed in the direction of any reference material): Whilst I mention ender here, I'm not fixed on them as a brand - happy to take advice/ lived experience on performance / noise of other brands. 1. What is the largest number of 90mm ducts you can feed from a single manifold (single MVHR unit - looking at Zehnder Q600 sort of size)? 2. I'm interested in a quiet system; when suppliers were quoting for 75mm they were insisting on twin ducts per vent purely to meet the BR spec. I have now managed to confirm I can fit 90mm (through holes in beams - I had previously worried 90s wouldn't fit, but they do). If I fit twin 90 per vent, will this just make it even quieter by reducing the flow rate per duct even further but still achieving the BR requirement at the single vent? 3. My investigation into attenuators previously was because I was looking into a branch system and needed them to avoid cross-talk; would an attenuator on a 90mm duct as part of a radial system reduce the noise? 4. I have a limited number of holes through the glulam beam, and so it would be preferable to achieve quiet running using attenuator on a single duct rather than running twin ducts. 5. If I had twin ducts feeding into a single vent, is there a single attenuator that would receive two ducts and then go into a single vent? 6. Has there been any study (formal, or just based on experience) into the noise difference between attenuator and multiple ducts. For upstairs, almost all our vents will be wall vents. We have 90mm studs and the duct is 90mm (having offered up, it'll fit). Where we put the ducts in the stud wall, I plan to line the wall with 9mm OSB either side before plasterboard. The studs will have rock wool sound insulation. 7. How much space is needed for the 90degree wall vents? 8. Although the 90mm zehnder duct (off-cut) I have offered up looks like I could get it to work, I would also consider the flat cross-section ('Flat 51' as zehnder call theirs), but note that the actual cross-section is less than 90mm; if I use these, do I need to double up (not according to their spec sheet), but I'm concerned about space and the practicality of bending them into the space available. Thoughts?...

Hi Nick, pretty bloody amazing eh. I played the patient game, polite, then just a bit of 'foot on the gas' at the end. But a hundred calls over 5 years, took a toll. Still freezing cold in the cottage mind, I skoot down to "Onoff's cabin" by the stream of a cold evening. Ace. Cheers, Zoot

hi BigJ, whose 'you both' though, me & my imaginary friend-? I live here with but 1 mouse, & possibly 1 sneaky ghost too. Actually I should ask about how best to run these things now I've got peace. At last!

I guess you must have been thinking about a detail like the below @garrymartin: In terms of the en suite @G and J I have actually made it even less intrusive with the above and also downstairs will have a relocated kitchen (new drainage through the front garden connecting to the existing as a new branch inside the existing chamber on the drive) so it should work all fine.

Hi all, Currently embarking on a self build project. Currently wind and watertight and in the process of insulating. The house is very exposed and will continue to experience terrible weather. Likely the one of the worst places in the country for wind! I have a continuous fascia vent all around the house but I have noticed during bad storms that the rain literally drives in. So much so that there will be a puddle on the floor. Its a 1 and ¾ storey house. I have attached a picture and I shall try to explain….Rafters will have 50mm air gap then 170mm PIR. This will lead down to the eaves where it will meet the PIR heading ‘up’ the wall. The PIR on the wall will be flush with the OSB. My concern is the water driving in and lying there, with the ends of the rafters soaking it up, and may end up leaking down the wall PIR and rotting out (eventually) the OSB. Is this fine as the air gap will ensure it keeps drying out or do I have a legitimate concern? When the wind and rain drives in it puddles on the soffit boards. Is there anything I can / should do?

Wooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo-Hoooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo Great news.

I would be doing that anyway - panel are £120 per kW plus mounts, so wouldn't you.

Not a deal breaker for building control, I agree, but if I provide ample accurate data, I expect them to use it. Also, to improve the result they suggested doubling up on PV which would have cost me unnecessarily.

If you have got a pain in the butt neighbour it would be safer. However, you can always ask for forgiveness if it gets pulled.

Don't pay them until they get it right.

Yes - not really that important l on the design stage, but very important at the 'as build' stage, make sure all assumptions are correct as well as everything else.

Think you maybe over thinking stuff. A heat pump cycling is a reasonably normal thing. If it runs for 10 to 15 mins it over comes any startup losses. As long as it's not 5 mins later you have no issues. Quick restarts are down to setting startup dT correctly. Don't get bogged down, thinking it's bad in mild conditions. It isn't.

I just got the design stage SAP report. Rather shocked at the predicted energy rating of C despite it being a build with high insulation, triple glazing, good airtightness , etc. So I read through the calculation worksheets to discover a load of errors. U values higher than the MBC thermal modelling that I sent them, MVHR completely ignored, generic oversized ASHP used, wrong building dimensions (like 30% greater floor areas and storey heights!). Entering the correct ASHP alone has dramatically improved the results and I have insisted they redo the whole report using the information I provided. Very poor effort. I suggest checking any report or calc you receive and don't be afraid to question and push back if it looks wrong to you. We pay good money for services like these.