saveasteading

Of course. But any time you open the door most heat will shoot out so I can't see the point. And the surface area compared to volume also provides a poor figure. Spending a fortune on sustainability for a building that is far from sustainable through the material/carbon content doesn't make sense. A shepherd would not do that.

That's quite good. More important is local variations. The industry way is remarkably and sensibly lo-tech, with a 3m straight-edge. Any completely straight timber will do. Lay it down (not levelled) and measure any gap whether at ends or middle. Then lean on the ends and rock it, and repeat. Any and all directions. 3mm or less is a pass and a few scattered failures may be OK too. I bet your floor passes.

Does that work for sand and cement? For a large area I'd use our cement mixer, but it's dreadful for getting loads stuck to the rear and the paddles.

This discussion prompted a lunchtime discussion.... so has been very timely. So it's decided to have a recessed matwell to the front door. We will box around an area on top of the pir so that ufh doesn't wander over. Then screed leaving a void. Them bring up to the necessary level in latex, then form a well with angle. And to sliding doors, just an over-mat that can be removed when we want the brochure look for the floor tiling.

AS mentioned above... clearance is a big deal. I've got 2 doors where mats sit too high and the door hit them. Not my mistake obv.. it was a concrete and lino floor and just putting tiles down caused a clash. Next time I woul cut out matwell. Thinks.... don't put ufh pipes right at the doors.

My concern on SIPS is my own ignorance. That to a large extent is because they don't seem to aim at the professional contractor market... which to me suggests that it isn't commercially competitive. I see the systems used in Architect led projects where the end result seems very expensive to me... so I (cynically?) suspect that they do target the public at self build exhibitions, and some architects who are , unlike designer-contractors, not so aware of the real cost. Hence quotes I have seen on here and elsewhere will exclude steels that may be needed, interfaces, perhaps even insulation targets. Thus beware. absolutely. To know how it works out in real life the pros on here need to know more. The self builders who have used sips may well be very happy with the results, but have probably not got experience of other ways. But they will advise of what, if anything, to beware of. My gut feeling suggestion is to you, as a self builder who wants lots of hands on and economy , is 'stick build'. It fits, and is sympathetic to newbies*... it offers second chances. But you won't see that at exhibitions. * that would include theoretical me if without builder help. Strip footings, stud build, timber cladding, timber roof, metal sloping roofing, or tiles.

That to me is decent justification. A kit reduces risk for the beginner, just don't try to change anything from a proven form. It depends on more than that though. Geometry, the ground and topography, how it links to the existing...and more.

Tell more?

On reflection I'm not thinking to add redundancy thtough extra piping, but to avoid petty savings. Eg does the utility room need any ufh? Miss it out, or half of it and save £30? Space the pipes further apart in some rooms? Likewise. There are places to save hundreds or thousands or tens of thousands and this isn't one of them.

Measured by bucket or bag, not by shovel until you have a total feel for how much a shovel holds. If you shovel the mix to different spots there is less brushing. It's not hitech but very important so that blocks are locked really solidly.

with a fan drawing air from the adjacent areas every time it is used.

I agree with @ProDave that bolts are advisable, not expensive either. But it might be tricky to drill unless you have a 90° drill. ring shanked nails or fully threaded screws at 150 cc, staggered.

I'm no expert but we are having a big area designed at present. There are additional pumps at manifolds.

You should have lots of fixings. The whole floor load, where raised, is resting on the fixings.

On top of what? Can you recall the price level?