Andehh

Go to screwfix, ask for 4 cans of expanding foam, and an expanding foam gun. Screw the can onto the gun, and pull the trigger in your garden to get an idea of the flow and how it expands etc. It's horribly sticky stuff, so don't get too carried away. All holes, gaps, areas you feel air could be coming in... Squirt deep into it and slowly pull the nozzle out. It will expand out, but it is very easy to cut back with an old stake knife 24 hours later. It's messy stuff!! YouTube videos will give you a good idea of what you want to achieve. That will resolve air movement. Or... Ask the builder to do this, it's a 15minute job. ________________________ Before you panic about the quality of install, how old is the rest of the house? Whilst the extension is highly unlikely to meet the HIGH expected standards of Build hub (we're all home building nerds!!!), modern building regs for an extension are better then a house a few decades old... So all needs to be viewed proportionally.

The shoulder months are also problematic for us (!) we are in a well Insulated house (miles off passive though... 2.7 airtight, 0.11 floor, 0.22 walls, p. 14 roof). We also have a huge amount of glass & very high ceilings of 3.2 to 4.2m, and regularly during shoulder months the house isn't cool enough to trigger the heating (21 - 22 degrees) , but the tiles feel cold under foot and you can actually feel quite chilly... Maybe due to the large glass? As a result we actually need to force the heating to come in (set thermostats to 24 degrees) for a couple of hours to warm the tiles up. We are also heavily zoned, which works well for us, as we have a very complicated design, so can fine tune the boost to rooms that need it, and leave the bedrooms etc

I find MVHR moves so little air the cooling impact of full boost on a cool summer night after a hot day, for an hour or two......nuffin!! So I'd be nervous at relying on it for heating, based on no real knowledge other then my own experiences. 100% UFH pipes in, pipes from manifold at where you 'could' do an ASHP, and put wiring in for it. Leave all capped off. So easy to do now, impossible in future!

EON Next Drive, Very cheap 8p from midnight to 6am,then slightly above average for the rest of the day. I miss tomato energy still

Using a multi cutter to channel out plasterboard, and went straight through a plastic water feed. Got a face full of water and a huge scramble dumping the sink cupboard across the floor getting to the stop cock! Then a frantic drive to screwfix to buy everything to resolve before the wife came home.

Keep us updated please, I have one I need to adjust but am too scared to fiddle in case I make it worse!!

Your very last picture, I would masking tape it off and then apply a very thick black bead along the bottom.

I know how it feels OP, I laboured over every bit of insulating detail for our place until our 2.4 x 7m sliding doors were installed (I was abroad with work). They removed insulation from cavity and back filled with solid concrete and sat the flush doors on them (from what I can tell). The installers refused any other installation method or approach due to our big, heavy and expensive the doors were, but it has left me a massive cold bridge which can be felt 1 foot into the room. Not sure id have accepted the risk of forcing them to do it differently, but I'm pretty sure mitigations could have been found for some if it (between them and builder). As the doors are nigh on fully flush inside and outside, nothing I can do about it. You can't win them all. (edit: also be wary of knock on implications, fix one problem may create others, and adding flex or tweaking installed doors may create other issues)

I think they do, you lose flow rate I think! I'm not an expert, but you can't beat seperate hot and cold taps on their own, but then have the faffage of adjusting temperature. Fwiw the aqualiser customer support is outstanding.

Just as a care point, from a total layepersons point of view those slates look neat, lined up and normal. You'd need to explain and evidence what's wrong with them.

We opted for big sliders, as 85%of the time it's all closed up, so maximum glass views. Lot less to go wrong as well!

Time for a new roofer, or start resolving yourself I’m afraid. Part of self building is knowing you get good trades, and (expletive deleted)ing shit hole bastard crooked ones (delete as required). We got lucky in having so many good ones... But I would piss on the electrician if he was on fire.

It's a strong look for sure... Based on zero experience at all, have you looked at external roller blinds, and squaring off the windows at the top?

MIL had a boiler pack up on her, 10 year old boiler. Blocked heat exchanger, likely caused by British gas not doing a power flush when they replaced it She paid £3000 for a new boiler and full power flush, from a local chap, last week... Must be an easy 25+ rads in her house. Prob £500-800 I'd guess for the flush? Made a massive difference to the heating of the property.

Been in for 2.5 years, every heavy rain has me walking around staring at the ceilings.... 🙃