Mike

I've had a BCO reject doing it that way because it wouldn't be guaranteed to be self-cleaning - that is, any 'residue' that build up where the branch meets the main channel would not get washed away. The sketch above is more-or-less identical to the solution agreed. No rodding point needed provided the bend is not more than 45° and is directly off / within a short distance of the IC (1 or 2m, from memory - check the regs / manufacturer's instructions). In my case no pipes had been laid so no issue.

No - only grapes & English wines, which can be excellent :)

I've dug up another resource that includes some useful content (as well as a lot of high-level stuff that won't be): EU-level technical guidance on adapting buildings to climate change

If there is no DPC in the wall - I'd guess there isn't - then if you block the moisture in the ground from escaping due to impermeable insulation or a DPM, it will tend to escape through the wall where it may cause a build-up of salts in the wall / plaster. I'd therefore be thinking about choosing the right hand side of your sketch but using limecrete in place of concrete. This isn't something that I've been involved with, but there are some pointers & further links at https://www.greenspec.co.uk/building-design/limecrete-floors-for-old-buildings/ You'll also need to convince your BCO.

I'd move the IC & add a 45° bend so that the WC makes use of the main channel and connect the SVP run to the branch. But make sure your BCO is happy.

In addition to the Building Regs, the 'principal designer' - i.e. you, if you haven't formally appointed anyone else to the task - is required to comply with the the CDM (Construction Design and Management) Regs. They make them / you legally responsible for eliminating safety risks during construction, cleaning, maintenance & demolition (or mitigating the risk if that's impossible) at design stage, involving a risk assessment. They come with some pretty severe potential penalties. Handrails or walk-on glass might be adequate solutions, but I see no obvious way of dispensing with both while being able to safely clean or repair the windows & the rest of the structure above.

A good list, though I'd tweak these: Larger roof overhangs for better shading and and rain protection - given enough space, consider turning the overhangs into a veranda or loggia High maintenance 'green' roofs are probably not an alternative that is sustainable in the UK climate going forward - select the right plants; it's even possible in a Mediterranean climate - https://encyclopedia.pub/entry/52357 Plenty of fruit trees - olive trees to minimise watering? Breathable (sorbative) insulation and high decrement delay wall materials wherever practicable - plus clay or lime based painted internal finishes External shades or shutters on South and West facing windows - consider adding them on exposed East facing windows too. Plants (vines?) running up & over a pergola would be an alternative No 'smart devices' whatsoever to go wrong/be held hostage to - a good idea not to rely on them (at least have a conventional alternative too), but the risk is somewhat lower if they're not exposed to the Internet ...and consider these (though most are more applicable to a whole house, rather than an extension): Minimise hard paving in favour of planting Make the building airtight + add MVHR for ventilation Make provision for natural cross-ventilation with openable windows on opposite sides of the building Use UFCH designed to allow cooling (if only in the future) Add PV panels Choose appliances with top energy ratings to minimise their heat output

There's some useful information on one of their other pages about that & the need for documentary evidence here : https://www.epcworks.co.uk/improve-your-epc/documentary-evidence/

Well spotted. It's an interesting case study, contains useful pointers and shows that there are some conscientious assessors out there (and why most wouldn't want the hassle). It seems though that they overrode the default values in rdSAP, rather than applying full SAP. Probably.

Good point Actually, that's probably working as expected as 20° is the 'normal' supply air temperature in 'fixed mode', and the Q series has an adaptive bypass (it can be partly open, not just on or off) However there are a couple of ways you can change that in the advanced settings - see this user manual extract :

That would be my guess (plus a little picked up within the unit itself). Varying the time the air spends in the ducts by changing the fan speed might test that - slightly warmer air on a slow fan and slightly cooler on boost? I can't try it on my Zehnder CA225 as I don't have a temperature readout.

I'm still deciding which hand to use in France...

Yes, mostly. The Building Regulations went metric in 1972 and the construction industry followed by 1975. However, to add confusion, some products haven't actually change dimensions while others have.

However such restrictions could be voided by the law, as has happened in Germany. I'd sit on my hands for now and see what happens.

The rise of the professional politician? https://commonslibrary.parliament.uk/the-diversity-of-mps-elected-in-2015-pale-male-and-stale/

That's a strange one - any obvious reason for this rule? It isn't obvious, but I've tracked down the 1998 version of the regs that includes an explanation. That says to limit the circuits to 5 or 6 and to optimise the routing of loops to avoid concentrations of pipes, particularly in hallways, but to insulate them if necessary. Which I would take to mean to avoid condensation on parts of the floor that would, if pipes are too bunched up and not insulated, be a few °C cooler than the general floor temperature. UFCH with cooling is pretty common France - apparently 1/3 of all new houses have it - and it has a long history, so their current regs (last updated in 2023) ought to be a good guide; I can spot a few things that have changed since 1998.

FWIW, French Building Regs say: Minimum coolant temperature entering the floor of between 18°C (near the English channel) to 22°C (near the Med), except 16°C if there are humidity controls, dehumidification or similar Automatic cut-off if the the coolant drops to 12°C No more than 6 circuits per manifold Circuits serving bath rooms & shower rooms should be isolated due to the high condensation risk Maximum 25 cm between pipes, to avoid excessive variation in floor surface temperature Room thermostats set no lower than 26°C

Interesting - not heard of that before. I found a BEAMA report here with more information. My French breakers don't have In/Out/arrow marking so presumably are bi-directional (it must be a Europe-wide standard) and do switch live & neutral. So safe for balcony solar if I had a balcony...

If I had a room big enough for an island, I wouldn't go down to 870mm.

Yes, this - 14mm is a common size for pea gravel but, as that's pretty distinctive, maybe you have something different? A photo may help. What are you wanting to use it for? For use in concrete it gets more complicated, with certain proportions having to pass through different sieves...

The French prefer showers? The British prefer baths? Would be funny if true, but sadly it's not. The Regs actually say a maximum of 125L of potable water, rather than hot water :)

That's an interesting idea, though is there any evidence? I understand the theory but wouldn't the input (output?) of heat energy to the air mass be vansihngly small small vs the input from solar radiation and other energy use? There's an evaluation for Paris for 2100 in English carried out in 2020. TLDR: If Paris growth continues through to 2100 based on current trends, and if optimistically efficient aircon is used to maintain 23 °C in all buildings, with the heat discharged into the air, and if other measures are taken to reduce temperatures (creation of parks, reflective roofs, etc.), then after day 9 of temperatures similar to the 2003 Paris heatwave (38°C maximum), the outside temperature 4 am would be up to 2.4 °C higher (2m above the ground), compared to using no aircon after day 9 of a 46°C maximum heatwave, the outside temperature 4 am would be up to 3.6 °C higher, on the same basis The model used does take wind and land use into account, among many other factors.

Would need to be a tried and tested one. Aircon increases the heat island effect so, in urban areas, you'd ideally use ground source heat pumps. That's already happening in some cities including Barcelona (in English), Munich (in English), Paris (in English), Lyon (in French) and Vienna, which plans to connect all buildings in the city by 2040 (detailed report, in English).

It would be interesting to have a definitive answer. For England & Wales, the rules are here and include: The approved methodologies for expressing the energy performance of buildings are: For new dwellings in England: the Government’s Standard Assessment Procedure (SAP) for the Energy Rating of Dwellings, 10.2 edition with March 2025 amendments For existing dwellings in England and Wales: the Government’s Standard Assessment Procedure (SAP) for the Energy Rating of Existing Dwellings, RdSAP10 edition which clearly says that RdSAP must be used if it's an 'exiting' dwelling. It goes on to say that The Reduced Standard Assessment Procedure is an adaptation of the Standard Assessment Procedure for use in the energy assessment of existing dwellings where, during a site survey of the building, the complete data set required by SAP is not easily accessible. So I guess it depends on the meaning of 'new' - which doesn't seem to be defined - and whether the complete dataset remains available. Maybe the existence of the complete dataset is enough to keep it 'new'? Maybe nobody is going to care either way.

+1 as an objective, but not always feasible in a small space.