Nickfromwales

+ 1 A valuable addition to the forum. . Welcome aboard, hope you don't suffer from sea sickness as it gets a bit choppy here now and then

Bit late to this party as I'm 350mph with work at the mo ? No problem whatsoever going under the walls, just sleeve or insulate it and you'll be fine ( 100mm wall transit would be 300mm of cover. 100 before - 100 under - 100 out the other side ). Loop method is the anti-Christ unless your in spreader plates, so go reverse / inverted whenever possible.

That method is for wooden floor as your finished floor. . The only thing I'd add to that scenario is fitting some fluffy ( Rockwool ) under the plates to make them slightly proud of the finished height. That way, when you fix the wooden floor down you'll be forcing the plates against the fluffy and ensuring good surface contact between the plates and the wooden floor. If you look at Frogeyes pics above you'll see how the plates naturally want to sag so that needs addressing with either method, eg fluffy or staples.

This method That allows you to cross the posi joists without cutting into them. Just remove the batten accordingly.

Dip under the top rail of the joist. Not ideal, but if you commission ( purge ) properly you should eradicate any air locks / pockets. Once full of water and treated properly with inhibitor ( X100 / similar quality product ) then it should be fine. Air vents ( automatic ) on both of the manifold rails is essential. .

With my rubi cutter there is next to no waste. I really struggle to tell which side is factory and which side I just cut. Money well spent . @daiking changing to a pukka blade will help a lot.

If your boiler stat was set too high then maybe. The cylinder would only have heated to the set temp of the boiler, so anything above 70oC may have started a bit of excessive expansion plus it would have been sustained so perhaps see if it all settles down now ?

FYI. My combi continued to produce oodles of hot water during this episode.

First and foremost, FIT THE UFH FIRST WHENEVER YOU CAN ! Retrofitting from underneath is simply hard work. @Bitpipe was in the same boat as you, but I managed to nudge him into 'doing the right thing' and he put his plates and pipe in as the build went up. MBC lads joined in and helped ( took over iirc ) to lay it and it saved a LOT of grief. The ideal set of events would be to allow for your posi-joists to have an 18mm batten atop, and then plates. The batten is required to allow you to cut the end for the pipe to transverse joist space to joist space as posi-joists can't be cut. Not a problem with regular joists btw. The main thing, either way, is to make sure the plates are fixed up nice and snug. I use an air powered stapler to fix them to the underside of the deck material so the heat transfer ( promoted by surface contact ) is as good as it can get. The only real tip for fitting from underneath is make sure you have a pipe decoiler, make sure you have at least 3 people on it, and don't be in a rush to do it. Pulling in 100m of pipe is a pain, kinking the last 10m piece and having to pull it all out and start again would be soul destroying. . Cut a few short pieces of pipe and get used to the minimum bending radius, ( before the pipe kinks ), by trying to form 180o bends in the sample pieces. That'll give you an insight into how far you can & can't 'push' the pipe.

Simple folks, just insulate every other pipe in the congested areas . 9mm wall armorflex will be ample.

The only thing missing is a cape ??

Yup. Just until you can see it's not got another full revolution left to go. "Plumbers eye" aka "Use the force".

Guys just being massively over cautious. . No need to run it imho and I never have. Is your slab concrete with steel mesh or floating screed / other?

Put about 25-28 turns of ptfe and turn it into the socket until snug and vertical. End of job. Don't overshoot and back turn it or you'll fack it up.

Chip away the internal wall / skim and use a multi tool to cut the sleeve. Screw the tap on and then push the bend fully on.

A square plastic trim will have a slight lip after the flat so should help hide the top edge a bit. Remember to keep the adhesive low down so you can fit the trim after.

A scribe and snap cutter would be far better tbh. Can you hire one for a day / weekend and just do all cuts in one go, so you have the raw material cut to size then you only need to cut to length ( after you've returned it ). ?

All depends if that means a shed load of filling. The bigger the gap the more filling you'll have to do, plus the foam is a bit uncontrolled if it's open to the room. Remember that coving is 80mm or so from lip to internal corner and 30odd mm of that is for the adhesive to land so you've got 50mm to play with. I don't like the plasterer having to start or finish a set that close to where it's visible as they always get a bit of a bell at the top and bottom of the set. ( bless them ). Plasterers also hate the foam as if they catch it with the trowel it gets into the mix and upsets them. The less foam on display the less it needs cutting back and the less loose bits to get in the plaster. Also, sometimes on a retrofit I've had to get the walls on prior to the ceilings going up, just to get things on and drying if we can't get the ceiling a up for any reason, so the foam option really does help out there. Yes, but there are dabbers, and then there are guys who have seen it done and have a go Prudence, and attention to detail are your friend, but a guy getting paid on meterage will always want to compromise that for a buck I've found. When the dab has gone off the boards won't move one bit, if dabbed properly. I use high expansion foam at frequent intervals to ensure the gaps are filled. LE foam hardly expands at all so I don't recommend it for this tbh. Just don't go mad with it.

Oh, and if you find a good plumber I'm happy to speak with them if there are any aspects of the remit they're unsure about.

An excerpt from the ERP guidelines update. Quote .... " The modulation of oil-fired boilers The major stumbling block is on the modulation of an oil-fired boiler. Generally speaking, certainly in the UK, a domestic oil-fired boiler typically has a fixed burner, a non-modulated burner. It simply cycles on and off when it reaches its required temperature. However in the current proposals, manufacturers would incur a penalty of 7% on the overall efficiency of the boiler. We consider this notion to be very unfair as we don't see any great difference in efficiency between an on/ off burner and a modulating burner. As a result we believe, a penalty which takes 7% off the efficiency of, for example, one of our oil-fired boiler will make it difficult, if not impossible, for oil-fired boiler to continue in the UK without changing to a modulating burner. A modulating burner would cost almost double the price of the present burner used in oil burners and also require an increase in controls complexity. All of which are relatively untried and tested so as a result we think it could signal the end of oil-fired boiler. In what is generally a price-sensitive market, the price of an oil-fired boiler would increase significantly, thereby reducing accessibility and meaning homeowners would probably be forced to look for other means of heating their homes." Delete his phone number. He clearly doesn't understand the problem. ( * ) There's no way you'll be able to run the Ufh direct via motorised valves and an UVC unless he proposed fitting a large, as in 300ltr, buffer tank. It's not about efficiency, it's about being matched to the heat load properly. Condensing is nothing to do with modulation, and it's modulation you'd need to lower the heat output to run the Ufh efficiently. As the boiler is basically on or off ( 100% of the heat capability or 0% of it ) then you need to use a TS or buffer to capture and hold the pulsed-in high grade heat so the Ufh can just gently draw what it needs and in the quantity it's needed. The use of a TS also means you can set the boiler flow temp and the TS stat accordingly to dictate ( near as damnit ) the return temp. That means you can optimise the efficiency of the boiler by staying in the ideal flow - return temp range to promote full condensing operation. ( * ) In the boiler manufacturers installation instructions ( MI's ) it'll actually say that you need to 'design out' any scenario which would result in the boiler 'short-cycling', one which the UVC and direct fed Ufh would instantly create . A poorly designed system could see you with no warranty as short cycling an oil boiler will seriously affect it's longevity, plus it'll be using a lot more oil.

+ 1. Thought I'd replied to this, sorry. I drill holes the same size as the foam nozzle, 8-10" apart, and pump in the foam that way. I get some bits of gaffa tape to cover the holes immediately after withdrawing the foam gun to stop the foam from spewing back out and messing the board up. After 20 mins or so, I remove the tape and clean off any foam that's proud, then just scrim prior to plastering ( or leave if your putting coving up afterwards ).

That's a shiver down the spine for any self builder. Brings a certain validity to this thread, that's for sure. When I worked on the ships, one hard and fast rule was no hot works whatsoever for the last 60 mins prior to site being unmanned. Smouldering fires ( or fires caused by smouldering ) were the no.1 problem as most hot works caused heat instead of fire. This thread has a lot of value IMHO, and should make all self builders sit up and pay very close attention to the content, and subsequences of not observing them .

@MikeSharp01 Any chance of that pic so we can round this off ? Curiosity is getting the better of me too cheers.

Wouldn't buying that house have been so much easier ?

What centres are the joists at?