PeterW

150x47 C24 at 600 centres is fine. Insulation will be your biggest issue though - you may have to go up to 200x47 for the depth required unless you use PIR between and below the rafters.

I would try and lay the DPM between the joists and stick insulation into the DPM “valleys” as it will also keep it dry. Are you able to take the whole floor up in one go or have you got to do it in sections ..? Is it floorboards or chipboard ..?

The 5% rules are here and it has to be supply and install https://www.gov.uk/tax-on-shopping/energy-saving-products

OK DPM - Damp Proof Membrane. Will also stop any air blowing up through the boards. How deep are the joists..?? That may dictate what you use, but it sounds like anything is much better than nothing ..! Got any internal photos ..??

How long has it been built ..?? If there is nothing there in the gaps and it’s been built in the past 10 years it should have a warranty. That should have a fair amount of insulation in there - what is your budget ..?? The crack looks superficial - could be caused by the joists moving about as you pull the boards up. I’d tape it from above with a reinforced foil tape then get a DPM between the joists and get them fully insulated.

Saw a really nice one where they created a plinth for the taps to sit on - basically mounted them in a box and went sideways into the wall for the water. Looked nice and you couldn’t tell it was a “fudge” Other option is to set a piece of Polystyrene in the floor where they will be going against the wall, then chop it out, fit the pipe work and then backfill with rapid set.

is that the one where the unlock key is hidden behind the logo on the page ..??? ?

No there should be a screw in the top side that pulls the top and bottom together

Ok so the quick way to check a spirit level ... Two big screws and a level-ish fixed surface that you can screw into. 1. clean the bottom of the level - properly ..!! Light sand to get rid of crap, cement, adhesive etc 2. Put the screws in to the fixed surface at around 50mm narrower than the length of the level. 3. Roughly level the screws, then put the level over them. Adjust the screws until the level shows perfect 4. Turn the level around .... and now see if it still runs true ..!!! If not, shim the level using a known thickness to see how far out it is ... I have 3 levels, two are within 1mm over 1m but one is a Chesterton that was very expensive ..!!

@OnoffHave you actually validated your laser is plumb and level ..??? Best way to check is a plumb line as it never lies ...

@canalsiderenovation it makes more sense to use the same construction method all the way through the house then you will get your levels the same. May need expansion joints at any significant direction changes - from memory you have three distinct blocks - and using sleeved rebar at the joins will stop any settlement movement. It would be a really simple job to do as a one piece pour with something like Aguila or another flowing / self compacting concrete over the top of the UFH. As you’ve got to pump your concrete deliveries anyway due to the bridge, this will be a win/win both sides.

Still not getting this idea of oversite and only 100mm insulation. Also, liquid screed and adhesive based flooring really don’t work well with laitence issues.

Super Leytex first two coats then anything you want. Short pile roller, pole and a big scuttle work best.

Tried Robbins Timber..??

Would only work when the GSHP is calling for heat, which is conversely when you would want heating, and your cold room actually would want cooling when heating is not required

Bet it is sub contracted to the same guys they use today ...

That or convert to male using a 3/4” hexagon nipple and then back to tap connectors.

Yes assuming the shower has a 3/4” female connection ..? You said tap connector which is the opposite to that

It’s known as a stem coupler but yes, a reducer

So you use a 22mm elbow and shove one of those in and you now have 15mm https://www.screwfix.com/p/hep2o-plastic-push-fit-stem-coupler-f-15mm-x-m-22mm/8401f Or you use a 3/4 to 15mm Titan and then use one of these. https://www.screwfix.com/p/hep2o-plastic-push-fit-equal-90-stem-elbow-15mm/8137f The straight bit goes where the pipe normally goes in a standard connector ..??

Because you don’t normally connect 3/4” taps to 15mm pipe. That is basically a bath tap connector you’re talking about. Can get it as a straight connector and use a stem elbow or Use a 22mm fitting with a 15mm stem reducer

It’s worth isolating on every end of an SWA. At about £16 each, a double pole isolator is not expensive and really important.

Your old wood saw will be fine as long as it’s not too coarse.

Sounds like it’s an Estimators Online or other type of standard quote system. I have to say in these sorts of circumstances go with your gut feel ... it will probably be right !

Usually means they have been using a quotation system that adds them in automatically. if you have a working foreman then a PM isn’t needed. Big firm ..??