-rick-

Hang on a minute. Are you telling us that you've just finished a true self build of a large property between you and your wife, while doing a full time job AND looking after a 2.5 year old? How??

Just checking: 1. Didn't think NHBC was normally an option for self builders - they only want to deal with developers. I believe their rules are generally more onerous than others as well. 2. I'm a director for a block of flats and we have been told we have no option but to use an approved installer for firedoor work (nothing to do with build warranties). I've not done any further research on this at this point but just wanted to highlight that there may be situations where it might be required. I would be surprised if required for a normal 2 storey house, but if you are doing a bigger project or some form of conversion it might be different. 3. Stepping back, you might want to look at why your design requires firedoors in the first place. You might be able to make some relatively small design changes and eliminate the need for firedoors in a 2 storey property all together. (They are a requirement for 3 storeys).

I'm not convinced this would be a big deal (at least compared to moving the bathroom to the ground floor). It's not like there is a heavy brick wall above to support. We don't know how the roof is built, if it is relying on the wall then the property is <4.5m wide so a chunky bit of wood covering the distance between the two exterior walls should be able to take the load (with the right engineering). An additional expansion to my option is to move the bathroom into the small room in the front. This is a much bigger job (if it's economically feasible at all) but results in a bathroom upstairs and 3 double rooms. It's a balance, at some point it's just better all round to find a new more suitable property rather than plowing money into the current one (that you won't get back when you sell). A simpler, cheaper, scheme now that either improves or doesn't damage the value of the property but that only buys you a few years before the kids grow and you need to move might be the better option than a scheme that creates the space you want but costs more to do than you will ever get back when you sell. My brother finished a major extension to his 'forever' home a couple of years ago. He spent far more than he could ever get back from the sale price but it didn't matter because he wasn't planning to move any time soon. Well guess what? Events have conspired to mean he is now moving. In his case, the extension while very costly adds curb appeal (in a way that moving the bathroom downstairs doesn't) and his situation means the excess cost isn't such a big deal but it just goes to show situations can change faster than you think and it's well worth trying to preserve options where you can.

and provide a steady supply of open box discounts to other local buyers Wonder which brand you'll end up with?

Reset to factory and start again? Consider whether there might be different firmware versions (for the Denon) that don't have these issues. (no idea how easy it is to downgrade). Are some inputs on the Denon more capable than others? Have you consistently used the same ports? I doubt I'm suggesting anything useful as technology has moved forward since I last dealt with this but just throwing out ideas incase it helps.

Just another idea: Personally, I wouldn't buy a property that didn't have a full bathroom on the same floor as the main bedrooms. I suspect plenty of other buyers are in the same boat so moving the bathroom downstairs may affect future saleabilty/price. I think the above fits space wise with 2 x double bed and 1x single/(or double bunk). Making this change doesn't require touching plumbing and so should be much much cheaper (it's possible this was the original layout when the property was built).

Yeh I wouldn't mix and match, either all eARC or all through Denon (unless I was bug hunting and wanting to test all cases 🙃) Curious why you want the Denon overlays? I never found them much use and the TV should show overlays for key things like volume. (Been ages since I had an AVR though as mine blew up and I never replaced it as I barely watch TV now).

AVRs have a long historical legacy of functions that often upgraders want to preserve. If you have a modern setup that supports eARC and don't plan on using multi-room or multi-output (switching between TV + projector) features then I suspect eARC is the way to go. Avoids a lot of the potential issues. Main downside is you have to have the TV/projector switched on for audio only from one of your sources if this is something you want to do.

Can you switch to plugging the devices into your TV and using eARC to connect your AVR? ARC isn't good enough for Atmos but eARC on newer TVs is.

I've not personal experience related to this so take this with a pinch of salt but I think you need to be very careful here - do a proper heatgain analysis. There are a lot of success stories here of using ufh cooling in the UK climate in airtight, very well insulated homes. You are adapting an existing building and with the general style of building in Spain I very much doubt your building has been built to those standards. Additionally, the climate in Spain is just much hotter so heat gain will be higher than we are used to here (both in terms of instant load but also daily demand - higher heat for a longer time during each day). In-slab cooling is limited by the dew point and whether you will be able to get enough cooling capacity from it within that limitation is a big concern. If you are comfortable targeting an internal temperature of 26-30C then it's easier than targetting 20C but still this might be a challenge. If your building is well insulated, airtight and has plenty of exterior shading to stop direct sunlight through the windows then this is all probably doable but likely still comes with conditions that you would need to maintain the internal temperature constantly, ie, not opening doors/windows until the outside temperature/humidity is similar the internal temperature/humidity. So a common situation of sitting outside in the cooler evenings with people going in out of the house would be more difficult. The other thing to highlight is humidity. Because of the dew point issue there is no dehumidification ability with in-slab cooling. Therefore, if you want to control humidity at all you will need an alternative way of doing it. I suspect the outcome of all this is that you will need to install fan-coils in addition to ufh cooling (could all be run from the same ASHP or seperately). Maybe you only use the fan-coils intermittently with the ufh being used for maintaining the environment outside of the hottest hours/dehumidification cycles. Anyway an interesting project and I'm very curious of the outcome. Good luck.

I've got to ask what's with the lifebuoy?

I'd really rather not! Seriously though, leaks are a right pain and I hope you get this solved soon.

You've convinced me not to build and underground lair, but I'm afraid I can't offer any suggestions for resolving your issues.

Depends how much light hits the other side of the panels. If located on a dark roof, not much light will make it through (I think some does through the gaps between cells). On a angle or as a shade over a structure with light covered ground as a reflector I believe it can increase output 10-20%

Yep, our governments (whatever party) so often tend to try an bullet-proof everything and it just ends up making for complex policy. Often keeping it simple and accepting some sub-optimal outcomes at the edges is the better policy. Now, if only we could undo decades of this in building we could make building much easier. Governments keep adding layers on layers to try and control policy outcomes, when more detailled building control could produce similar outcomes with much less cost.