G and J

Ah then that’s the answer. My ASHP is going half way down the garden. My man cave is at the bottom of the garden, and will have a nice big sound bar connected to my smart tv. So I solve the ASHP noise issue by getting to enjoy some serious beats to exercise too. Brilliant. 😉

Is that the forum equivalent of a blank look?

Because they ‘know’ heat pumps are worse because aunty Enid’s friends neighbour’s son in law lived in a council house with a huge noisy heat pump dumped right outside their bedroom window which ran 24-7 but the house was still cold with luke warm rads and a electric bill they couldn’t pay.* (*A fictitious account based on real life early ASHP installations in social houses that I’ve seen first hand).

Survey done. I find the whole attitude to ASHPs fascinating as we talk to different peeps re our plans. I know my new neighbours would much prefer us to keep gas. Ho humm.

Is t Is the floor plan 2500 sqft? if so not sure the figure above ?

Ah......is to be joined to the house, block not TF, slab fall towards road but......

I was thinking of a 1:100 slope down towards garage doors......not a good idea?

+1 With a passion.

Bet they said that about asbestos once, long ago. When one embraces relatively new technology, or materials, or indeed design practices, one is taking more of a risk. That’s the good news about being a wrinkly self builder. Mistakes will only be a bother for a small number of decades, tops.

I’ve no experience to offer but intuitively as the majority of the year the bedroom supply vents will be moving very slightly warmer air into the bedroom I struggle to see why a perceptible draught would be created, given the low flow rates involved. Like you that would reduce duct runs and for me it would reduce the number of penetrations in our airtight membrane, so we’ll done for a brilliant idea. I think I’ll keep the bathroom extracts in the ceiling though.

From what I’ve read (yep, I’m yet another poster who masks guesswork with confidence) MVHR is only energy efficienct if a fairly good level of air tightness is achieved. That would seem to indicate that a centralised system is not ideal. Reducing humidity is likely to increase the heating bill whatever system you go for but in your position I’d look at things like extractors or dmev. Nowhere near as sexy but cheaper and easier methinks.

Ok, so a trained hamster in a nappy.

Cleaning! I thought MVHR meant I never had to dust or vacuum again? Being serious my current plan is to have limited access to the manifolds and thence continuous duct from manifold to terminal. Will I be sending a trained hamster with a duster through my ducts? Or in reality is cleaning a very rare event?

We intend to use Ergovent which are plastered in. Not sure if it’s too late for you for that or if you prefer surface mount. https://www.ventilationland.co.uk/en_GB/p/frameless-square-ventilation-valve-ø-125-mm/18709/?gad_source=1&gbraid=0AAAAAB0qKPCDyeAp9KFPi3NPY7szWhSMM&gclid=CjwKCAjw9p24BhB_EiwA8ID5Btq_n6a3GfORlhvHEiCKGcuqGAnenTP08SzNlKxntU6VtUF3h__QchoCb4EQAvD_BwE They do come with an adjustable baffle I believe. The square middle bit is held on by magnets so can easily be popped off to adjust flow.

All very personal taste I know, but if the ensuite is steamy will opening it up to the closet work.....I also woudn't fancy either having to wait or worse, walk past someone on the loo......I know true love knows no bounds but.....

So, the process is something like: Obtain planning permission. Do building regs level design. Get SAP rating (as designed) to form part of building regs submission. Submit to building regs for approval. Change stuff as needed and get building regs approval. Get quotes. Appoint peeps who complete their extra bits of design (like timber frames and b&b floors and stuff). Purchase warranty. Build while building control dudes inspect. Get as built SAP rating. Get sign off. Live happy ever after until you can’t help yourself and you decide to build again despite the combined advice of family, friends, therapist and probation officer. I may have got that sequence wrong, if so please correct me. But the question I’m struggling with is design changes. Say after getting building control approval you have a better idea. How does it get built in? Do you just do it and hope BC and warranty company like the new design? Is there a change process like there is for planning? Is it usual to seek agreement from building control for changes before and during build? Same for warranty? There’s so much I don’t yet feel I should, so demystification appreciated.

It isn't bad at all. less than rain on a skylight. I've asked clients what they think of rain noise on a metal roof (in offices and schools) and they either don't notice, or like it. That’s good news for my man cave then. Mind you, the sound bar should drown just about everything else out: low flying fast jets; earthquakes; even the music from an Amazon delivery driver…., etc.

I almost fell for that. It would be like living in a biscuit tin when it rains. I’ve spent time in a ‘72 bay tin top. You hear every drop, big time.

Ta. Is this an accurate cross section? So presumably the foil was your air tight layer.

If I promise to be your bestest friend can I have a look at yours…..?

So, to restart my thinking I’ve gone back to basics. Here’s our flat roof. My first question is: Is there enough room to get a cold roof sufficiently ventilated using those little upstand vents and the fact that the skylight mucks up cross flow?

So you’re really pleased to have bought a plot in such a picturesque place then……. 😕

I like copper. It feels good to use, very satisfying. But in our build we are going to use Hep2o. House I’m sitting in now I did in copper as plastic wasn’t ‘of age’ back then. 18 years ago we did a full refurbishment of another property and I used Hep2o. In hindsight the mistake I made was treating it like copper. I don’t mean I melted the joints with a blowtorch - I mean I used elbows and connectors in the walls like I would have using 3m copper lengths. So for the build if all goes to plan there won’t be a single joint buried, just lengths of plastic pipe. And I appreciate that using copper for the final feed to each rad looks good but it does mean buried joints, and as one can buy cosmetic pipe covers why not go plastic all the way?

Crumbs guys, thank you. Loads to think through. Standing back from this a moment it’s interesting to contemplate how we’ve got here. We drew a picture, including a flat roofed bit for preplanning which got a thumbs up. We thought we’d drawn something pretty standard from a buildability point of view. Architect then turned our picture into a planning submission and we assumed any buildability issues would be flagged then. Some where but not one with the flat roof. Planning obtained architect went into building regs design. This flat roof is the last bit, maybe because it’s the worst bit or maybe because it just happens to be last. We’re on a fixed price contract for getting us through building regs, and perhaps the architectural technician who’s doing the work is aware that the amount of time spent on our design is now coming to an end. We could simply accept the initial design, though I have concerns about how insulative it is and how easy the little upstand vents will be to get right and keep open. So my instinct tells me that research here may bear fruit. Certainly I feel my many hours spent considering wall options/build ups/etc. helped me feel informed in the final debate that decided what to go for. I even kid myself that the design is a little better for it (but I’ve been called deluded many, many times so who knows?). And that’s where I am right now, back gathering understanding of factors and options. Perhaps the best I can hope for is to balance the slightly over conservative approach of the architect, but I’m driven to do my best. But how do I do that given where I am right now? Do I simply accept the first design, with the intention of finessing later? Do I pause the process now and engage another party? I’m not 100% comfortable with the process. It seems to be that key design elements are ‘done by others’ (steels for racking strength, to hold up rear gable and to allow thinner posijoists; foundation design; beam and block design; etc.) only after building regs submission which seems daft to me. And there seems to be so much focus on ‘getting past’ building regs/control. They should be our friends, a vital asset to help us improve our build quality yet more. Sorry for the quasi-philosophical dump, but I woke up early and sometimes it’s hard to work out how to think about the problem at hand.

That made me laugh! Sorry! I can’t imagine using the trapdoor. I tend to put a ladder against the side of my tower - firmly binding the top rung to a convenient bar so the ladder doesn’t push the tower (too much). I’ve been known to have two ladders tied on for bracing for that matter. But these things always waggle around a bit, and the more one thinks about it the tenser one gets so the more they waggle!