Nickfromwales

Yup. With 200mm you could go in the top face of the lower 100mm layer, with 28mm Hep2o pipe ( run point to point with zero joints in the slab ) and insulate it with 13mm wall Armaflex insulation. Simple choice is to go under and rise up where required with the Duo. Depends on your multi-tasking skills / sequencing etc, but can be done either way ( just DEFO NOT in the screed ! ).

Tape isn't suitable for anything other than uniform surfaces with complete access, plus there's a much higher chance of them not adhering 100%. Foam, foam, and thrice, foam.

I buy 12 or 24 at a time with the amount we go through on full installs. Every project is an airtight house so this stuff is brilliant at sealing penetrations etc. Foam. KISS. Get a spray bottle and apply a fine mist of water immediately before foaming, working with the process - spray 1m, foam 1m, and keep repeating. The whiff of water makes the foam cure so much better / faster. By the time you finish going around, you'll be able to use a padsaw or similar to cut the first section of foam back flush with the wall.

"The power is in your hands". Go kick their arses, and then cancel your worthless cover plan.

Does "being unhappy" then magically provide a full set of plumbing tools and the experience / knowledge of how this should be stripped and rebuilt / re-plumbed? Tough crowd!

The best option is to cut into the black pipe and fit a solvent T with a reducer to 21.5mm ( condensate pipe ) glued into it. Those retro-fit connectors are shite tbh. This would be fit and forget then. 30 min job at most. Can't you get the boiler installer / plumber back to do this?

Undo the white nut, below the solvent weld elbow. Have an old towel stuffed in there to catch any water trapped in the pipe. The nut should be a little over hand tight, so you should be able to remove this with relative ease. Get a pipe cleaner or similar and then insert it down and around the elbow fitting ( white bit connected to the black pipe ) as I know British Gas for one fit a stupid and unnecessary ( plus problematic ) non-return valve at these junctions. You should feel an 'obstruction' in the elbow, and if so you will need to get the non return guts removed and then just re-fit the nut and pipe back on. That will be the end of the problem I think. I've been out and removed loads of these tbh with identical symptoms. BG even install these outdoors, uninsulated, and as they harbour a little residual water at the lowest part of the pipe, they then instantly freeze!!

In a nutshell, yes. Nothing will 'build up' in the void filled by the foam, as it will be filled up by the foam! If it's not porous or adversely hygroscopic then it's suitable for preventing damp bridging. It is imperative that you have prepped this meticulously, and have cleaned and primed the surfaces well.

All the ducts need to be subterranean, and brought up through the slab. I hope you've allowed for at least 150mm of insulation? 200mm is optimum. Do not run these through such a thin screed, as you'll end up with hot spots and very little residual cover over them ( by the time you fit at least 9mm of Armaflex over them. They'll get significantly warmer when servicing DHW don't forget! Install some pre-insulated pipe for the ASHP, such as... https://pipetek.co.uk/products/32mm-microflex-duo-heating-pipe-kit?variant=29979663466614 ...which is what I use on almost every ASHP installation we do. You can install this yourself prior to contractors coming in, so you can save some labour here, plus it will be a better job. Bury this at least 400mm deep in the ground if possible. Run 2x 50mm ducts alongside it for 230v power and low voltage signal cables.

You want to ditch that cheap foam ( open cell ) and use Illbruck 330 ( closed cell ) foam. Goes off much harder, and won't bridge anything, is air and moisture resistant etc. https://www.dortechdirect.co.uk/catalog/product/view/id/5664.html?gclid=Cj0KCQiArsefBhCbARIsAP98hXQJH_IageT-_cHrAyRaxDPZS_RQ6DaqHGqAD-Koxv5kvgILSWaz7hgaAk8SEALw_wcB I don't use anything else these days. Excellent stuff, and ideally suited to your current requirements

Misrepresentation of goods act? Anybody? Indeedee.

Ah, yes. I'll chalk that one down to the good people at Beavertown, and their delicious "Neck oil".

Don't let the door hit you on the ass on the way out Medium rare, no less. 🙄

This is what was used for heave on my current project. https://www.google.com/shopping/product/1?q=cordek+heave+protection&prds=epd:18157365360563409597,eto:18157365360563409597_0,pid:18157365360563409597&sa=X&ved=0ahUKEwjbmqKwsaD9AhWRTcAKHWvhAnEQ9pwGCAU

His blood is 67% potato, corned beef and onion, plus 22% pastry. It doesn't conduct heat very well. Such a shame when they get this way.

? Clearly not. I'm more concerned about the vanishing airbrick??

You're a god-damn legend. Pasties are on me.

CDM and H&S?

Structural engineers aren't going to do anything more than structural engineering, and nor would you want them to Your general builder 'could' become your principal contractor, but they'd need to agree to officially adopt that role, otherwise it will land in your lap. Read up here, a lot, as there is an absolute wealth of info here regarding this subject

You would have had a proper tap connector. These clowns took the lazy route, and just started cutting pipework for no good reason. Fill valves in the cistern have an industry standard connector, and replacements are manufactured to allow an 'alteration-free' replacement. Tossers. Get this changed for free, then cancel.

Cancel it. Put the money into a glass jar each month. IF or WHEN you NEED something doing you'll have plenty of money ( of your own ) to appoint a company which isn't a sharky shit-show such as these legalised thieves. British Ass more like. Dyno Rod are drain un-blockers, not plumbers. Why the feck would they not have cut the pipe lower down and used that to absorb the length of the flexi. OR ( drumroll please ) just have used the exiting tap connector which would have been a like-for like swap?!? Cancel your contract, and save a boat-load of money over the next x number of years where nothing breaks. Biggest scam ever, and if your boiler fails they'll just cancel your contract for you, stating that the boiler is obsolete, and give you a massively inflated price to replace it.

When my "outy" goes to an "inny", it's time to get out

£40 is the cost of a tub / kit. You buy multiples to complete the area. I've posted over the years in huge depth regarding this. They don't call it "tanking solution" for nothing !! Tanking is via a liquid or a membrane, but almost always a combined effort using both is the 'norm'. Eh?

I’m surprised you can remember that far back lol

Not accurate. Tanking can be done, very effectively, with the cheap liquid ( paint on ) solution, with excellent, long term reliability. Other systems like Impey utilise a very expensive self-adhesive membrane. Not necessary, just an option that is out there. Further disagree, massively. Tanking solution applied correctly means that you are "tanked", end of. This is dependant on it being applied according to the manufacturers instructions. I did a wetroom in a house, over timber floors, on the 2nd floor. This was for two ( careless ) teenage daughters of a wealthy couple. Clothes and water everywhere. I spoke to the client about 3 years after installing 2 full bathrooms, the aforementioned included, and he said to me, "I wish I had you do the others, Nick" as they let him down. 'Mine' are still in and being used, hassle-free, some 9 years later.