saveasteading

Exactly. There are chances and hassles I'll take on for a personal project, whereas for a client I'd accept the norm. I've been challenging the easy norms for decades. It results in better knowledge, the good ideas becoming standard details then improving every project thereafter. The bad ideas rejected and knowing why. Back to the original post. We don't want heat loss from the hot pipe, especially to the cold pipe. I considered the @SimonDproposal for a bit, using the insulated pipes in a duct... if it ever failed they could be pulled out and replaced with uninsulated pipes. This could be a good standard method where there doesn't happen to be 300mm of insulation. But the 2 subbies are now on board my way so it will go alright. I've even found 2 lengths of so-called barrier pipe with the magic layer of coloured plastic... it's just normal pipe. The guidance above is sensible. Building moves and pipe fails? wont happen: each pipe will be continuous so no joints. They can move within the eps. They are 150mm below the screed so won't be screwed into. The ends will be apparent as the pipes will pop up into view. If ever the pipe needed changing, there is tile, screed pir.... not destructive. I know this is ott, but we have this opportunity to exceed expectations. As for the bco... they trust us. We welcome any query. When we adopt novel approaches we explain. If necessary we present it formally for their files. Only my time has been expended and I am foc And your time for which thanks

Such an important bit of advice. Most bolts are overtightened.

Yes I assume this is the concern. I can't see much chance of a failure if the pipes have no joints where they run under the floor. And the insulation provides a slip layer and cover. And at worst, it is not structure but tiles over thin screed over pir. I can see why it's a pig to install whatever we do, and why heat loss will be low on some people's concern list. Not much chance of removing the island though: it is decided at a higher level.... and they do like the idea of cold being cold, and hot being hot. For my interest... hypothetically, if 2 uninsulated pipes were in a duct and one had to be replaced... could they be pulled out and new ones dragged through?

That would preclude them being threaded through studs and joists, and behind boards, fitted units....

Thanks, I'll check these out. It's not me who says to use barrier pipe... it's the others.

'Embedded' to me means locked solid in concrete or masonry. ie there could be differential stresses that could break the pipe or a joint, and cause water damage. That is sensible.

I've done a nice sketch. the verdict? OTT and not what was anticipated, but OK. And the pipe is to be 'barrier' pipe!. I've looked at suppliers in Hep2O and Flomasta (Screwfix) . They both describe the option of barrier pipe but never mention what they mean by it. I guess it's just that if people want to ask for that , then let's use the words and sell it. JG Speedfit BPex from Toolsation says this: The pipe is made of five layers, and in the centre is a coloured oxygen barrier to prevent the ingress of air into the system - this reduces the effect of corrosion on metal components. But if eps is ever found to emit chemicals or death-rays then the colured layer of the barrier pipe will be there. Phew. It's only going to cost an extra few £ so I'll let it go. Hep2O say theirs comes off the coil straight, which must be good thing.

Agreed. It looks fine, but not widely stocked.

I was hoping you might respond. That's pretty well what I had in mind so, by default, is correct! I will draw a proposal and send it to our m & e guy, to ask if there are any problems with it, and will he supply the pipes or otherwise tell us what to embed. As I see it, we lay the 150mm eps, then lay the pipes on top, parallel and about 100mm apart. Whether the pipes will tread into the eps or need notches, we will see. Then pir on top. If we had thinner insulation I'd use 2 layers locally. Where the pipes need to emerge we will box around so the pir is no screened and is exposed for cutting out.... so marking out the runs will be essential. @SimonD your links have been interesting. The product looks good but seems mainly to be for ufh. Where it is aimed at domestic water feeds the thing that bothered me, on reflection, was the long waffly statements without much backup. It looked as if a keen nee recruit was asked to bulk up the spec pages. The supplier links ended up at " no longer stocked". @-rick- I think you said the same. Thanks all. But further discussion or disagreement is still welcome.

None of the links seems encouraging. They skirt round the subject and don't give any numbers or details. One of them I can see is for heat pumps. i guess most people just do whatever, and the water works, so there is no feedback. But this is a chance to strive for perfection.

That's correct. I hadn't thought about condensation within the duct. It would be a closed environment and not get wetter, but maybe it should be inset within the insulation. the hot feed would be at about 40 degrees, and the cold say 16?? so that's quite a difference. The duct would warm up to a fairly steady 25C or so. I was thinking we might just bond the duct to the lab with expanding foam. or maybe put 25mm eps under. But the pipes themselves? mdpe will be better than copper.

Continuing from a previous post, we are setting pipes and ducts on the original concrete floor, before insulating around and over them , then screeding. 150eps under 150mm pir. For the kitchen island sink, we need a hot and a cold feed. In my opinion they both need insulation to avoid heat loss/ transfer, especially from one to the other. However, the general builder who is putting in the pipes says that we should have both pipes inside a single duct and to use barrier pipe which is self-insulating. I've checked and see that barrier pipe is for contaminated ground, not for insulating (although some non-expert sites say it is insulating). The plumbing contractor now says the same! Both these guys are trusted and very good at what they are good at. In my opinion they have fallen for the hype from the plasterboard companies and then superfoil, that a layer of aluminium is insulating. I assume that a pipe with an insulating layer (armaflex etc) is tricky/impossible to get through a duct. I don't want 2 taps, labelled 'slightly cold' and 'slightly warm'. Your guidance please.

@Gus Potteris very knowledgeable and practical. I use him because I've forgotten so much structural theory. But possibly too far away from you. I can see he has seen this post but hasn't volunteered... because this isn't a marketing space. You could PM. In that case I can't help further. The market has slowed slightly so there should be capacity. Thus i suspect it is location, budget or something you aren't telling us.

Incapable seems very unlikely. Let us help by telling us more background.. something is putting them off. Otherwise the unwillingness may continue.

Oops, done it again. I've been forgetting which thread is the annoying one.

How do I turn this subject off? I have deleted "follow" but will still see anything from the respected contributors whom I don't want to turn off.

Is there a brand that is controllable to some extent? I'm thinking someone said illbruck was best.

Water is great isn't it. I'll probably dilute the pva a bit too to minimise the content. Sorry, I meant if using expanding foam...

We will have a membrane over it all for separation. I think I will trial a mix of eps granules in pva. This should trowel into the odd curves around the pipes and up to whatever level, where it can even floated to a controlled level. Big gaps can have lumps of eps or pir pushed in as bulking. This currently feels like a ready solution that will maximise insulation and provide even and adequate floor support. I inherently don't like expanding foam because it is the easy resort for fixing bodges (and has cost me a lot of money and aggro when Mr Nobody has used it badly). Where I see any I examine closely for what it is hiding or fixing. But maybe it is the pragmatic answer here. I need to buy a few cheap floats on the basis of writing them off?

Which doesn't alter the party wall conditions or process. You must still do this. The contractor's assurances are not enough. Regardless of what the bco says (they have no liability) you must have approval and detail from a Structural Engineer or or a very technical Architect with capital A or Chartered Surveyor who has both the knowledge and insurance cover appropriate. The risk of not having this approval are huge. Not only might there be a problem to your or the neighbours' house but it could create difficulties to you or them in selling or getting a mortgage. The neighbours' party wall surveyor will also require this proof. If you are using one of the very big piling contractors then they may do all this for you.. but I suspect yours is a small, general contractor.

0.6 for a traditional 3 core wall with lime. In normal conditions: and perhaps the internal skins still need to dry out a bit.

That's very unfair. Often we give our best opinion , hurried between other issues of our day. Sometimes this can seem blunt. Sometimes there are other opinions or we might be wrong. And often we realise that only supporting responses are wanted. So please be more positive and patient. Bullying it is not.

And answer the questions please. Do you have a structural engineer? Has building control agreed to these piles? Some mini piles are utterly unsuitable for houses. Permitted development applies to planning only, not building regulations.

@Wadrian I've looked at your previous queries. You don't appear to respond to comments. Please respond in some way so we know this is real and it's worth us being engaged.

@Wadrian you may not like what we are saying but do stay engaged. We are helpful and constructive. Better a delay now than huge issues later. Do you have a drawing we can see?