Andeh

Are you sure you can't get a sectional garage door, and fit it to the inside of your pillars? You'd lose width, but you'd gain your 100mm and spare? .... I'm pretty sure you can!!

There really isn't a good way around this! Removing all that would not be without the need for a structural engineer type assessment. Would probably be easier extending the garage forwards somehow, as unappealing as that may be... You're not dabbling with wall collapse risk that way!!

Give them a good brush and gentle power wash to remove dust, then dry thoroughly!!!!

2.7 for us, but then we have a few sliding doors which suck(!) for air tightness.

Always worth maintaining a focus on the payback period, and perspective. End of the day the UFH will work fine as OP has designed it, and for a large retrofit, the extra £30-50 (??) per month in heating costs for the heating season isn't a disaster vs spending 5 figures digging out a subfloor to increase the insulation. OP has accepted the compromise, and I see his reasoning, as there is more to a design then raw efficiency. Buildhub is biased towards the raw efficiency to achieve top top 1% performance, but not everyone is as focused, and a top 15% performance vs average housing stock is fine for them!

Lots of love for this thread!!!! Yep, I'm another one. 10min applying sealant.....30mins trying to get it off everything I've managed to smeer into! Expanding foam is another one... One does not simply apply expanding foam, without making a mess of everything within a 5 foot radius!

For our porcelain, hot soapy water and a good broom keeps it perfectly clean! Even under a willow tree, and bird shit.

What about waiting for the hottest, longest dry spell possible.... And pour several litres (and several litres more...) of clear water sealant/weather proofing type stuff over the entire suspect area. Absolutely drown it in the stuff, in the hope it trickles through all the tiny joints and soaks in.... Then sets?! Preventing water soaking through. Nothing to lose, other then a £50 note! Ps... 3am was me wondering if we've over spent on a dining table, but (expletive deleted) me it's nice to have normal people problems vs wondering if the main sewer is deep enough to avoid the need for a pumping station, or the sleepiness nights over £40k of windows which weren't per our design....

Trickle/ladel more of the black stuff to give you an extra couple of inches then relay blocks!

One day human kind will create technological magic that will enable us to trace leaks properly. We can put a man in the moon, explore the deepest oceans.... but leak detection still involves trial & error and lot's of poking around and hoping for the best!!!!

UFH everywhere, and A2A in key rooms for short boosts of heat, and cooling during the summer. Unbeatable combo!! Slept like a (chilled) baby last few hot weeks!

Bitumen paint, a friend to many of us in these situations!!

Home insurance policy? Accidental damage etc?

Also be keen to see if ever an option ourselves!

Is that where it puddles by any chance or drains? How long since it's rained for you? We have it odd that after rain, as it dries... Some individual blocks look wet still, then lots around are dry... Almost dries like a checkerboars. Soon all driws the same.

Check check and check again! Some bellend changed the style of the windows, and builder failed to spot it... So we ended up with windows different to what we wanted to. Caused a lot of upset for many weeks... Our biggest build emotions.... But now forgotten and accepted. But windows can be one if the biggest single purchases, with so much choice and made to measure etc. We have the smart ally system and very happy with the windows, we just didnt want a central mullion l... Rather a single large pane of glass... But someone added the mullion be cause our windows were too big for single pane, but nobody told us until they arrived.

Anti crack mat for sure! We installed one, and still see a few cracks in the grout which need redoing, but touch wood no other issues. Similar sqm to you, laid in 75mm ish sand and cement.

Ain't water a bitch... Who needs it!!! You wouldn't have this issue with gin! 🍸

On the brightside , playing with concrete is always good fun! So you did that!!!

Ah mate

How often do you get flooded? During those circumstances I'd imagine you're gunna have bigger worries to work through!!!

How much insulation have you got below the UFH? And in the house in general? Tog slow the heat transfer , but don't stop it. Providing you have a good amount of insulation below you might not need to be too over zealous with the underlay, if there is a risk of compromising actual usability. (Ironic as we spent a couple grand on low tog carpet underlay, likely with a ROI beyond my own life span... But hey ho... )

Very satisfying!

Are you able to dish it/level it to push water away from the wall??

That gap between the block and historical stone work has got to be a major weak point to focus attention in?