Conor

As they will be embedded in masonry that will have a high moisture content, they need protection from corrosion otherwise they will corrode and eventually (decades) fail. Your engineer would have specified this requirement. No fire protection needed as they aren't exposed to a flame risk.

If those steels are in the outside course of block work, they need to be either galvanised or bituminous painted.

I couldn't find any that would do both ICF and basements. So that's why I went with a main contractor as they'll provide it.

The conservation officer stipulated no fewer than 12 aesthetic recommendations for our application.... From no PV panels or PVC windows, real stone instead of stick on, cast iron rainware, etc etc. Our architect rebutted every single one of them. Try and find out how bothered they are about these.

We allowed a 2.5% project deposit, followed by four main stage payments and a final 2.5% retention. Seems to be a fairly common way to do it. Remember vast majority of builders have credit accounts for suppliers, so the need for any big lumps of money upfront can't really be justified.

Speak to Scott at Lindab. I contacted them to buy ducting, he asked if I had sourced MVHR units, I said I did and told them the price and spec of the brink from ventilation land. They pretty much matched it (within 150 quid) with an equivalent Zehnder unit, and a good bit cheaper than BPC. It's a superior quality unit (according to my friend that is a designer and installer of various systems) and have it in stock right round the corner from me. They also did a design and a fully itemised quotation. It's (hopefully) coming in about £6k for two Zehnder Q350s and all the controls, ducting, plenums, air vales etc for our 315m² build. (Original quote was £7k, but they included the expensive WiFi units and twin 63mm ducting instead of single 78mm)

The slabs work it's easier to have a "slot" than squares as you want to minimise the number of cables you lose. Your slab company will suggest what's possible. In our case, we left a few strategic gaps between slabs, and where we had a slab run parallel to a wall, leave the side of the slab short a couple hundred mm. When we've all our services though, we'll shutter the underside and pour some concrete in. I've left a gap like this along one wall of the main bathroom, so all the waste pipes, vent stack and MVHR ducts to the first floor will come though here. I'll then build a false wall in front of the gap to hide the services. Coring a 116mm or smaller hole in a 150 slab is easy enough, you just need to avoid the cables which are normally 150mm centre to centre.

Yep, as above. We made numerous ducts though the walls using 110mm PVC pipes. A single opening for three services is easier to seal than three separates ones. If you don't use them, ease to seal up and cover over.

I'm convinced that some people assume you have tonnes of money because of what or where you are building and just quote silly numbers as they think you'll pay it regardless. We're building on one of the most desirable streets in the most desirable town in northern Ireland... There are more Porsches than Peugeots. We are far more likely to have a Peugeot than a Porsche 😅

So in the summer you can have it set to DHW in the morning and cooling in the afternoon easily enough?

Thanks David. I think I'll do the same then. Did you put rads in all of the rooms? We'll have four bedrooms and two bathrooms. Have you investigated a cooling setup yet? Something I'm keen to have the option of, even though it'll be rarely used.

Ok, that design is very reasonable and I wouldn't push him too hard on it. Just make sure the rebar is all bent and cut to spec at the factory as it'll be a nightmare to work with on site. I am assuming you will have a contractor doing this all and not yourself!!!

How are you finding the usability and reliability of the coolenergy unit? Good point about the rads, think I'll do the same. Are they on a supply each from the.manifold or shared?

Over here, the DPM normally goes on top of the concrete slab and under the insualtion. 100mm PIR isn't very much, and I'm worried that your architect only specified 75mm. What's their insualtion / cold bridging / airtightness strategy for the rest of the build??? What's your predicted SAP?

Is that a 240m² slab? As in you're building a three story, 720m² house?! If so I'm not surprised by the spec. It's a normal amount of steel but the 20mm bar is unusual. It will be very heavy and difficult to work with. Definitely ask if you can use two layers of mesh in the slab and 16mm starters.