Tim_C

It's a slow section of un-electrified line (I believe 50mph), with no points in the proximity. I don't hear any 'clacking' and from what I can see its welded rail. So I believe the main noise will be external from freight diesel engines and squealing of freight wagons. Thanks all - sounds like best to avoid PIR then 😅 The downside is it narrows the field a lot in terms of TFs from the usual TF suppliers, which are high performing thermally (but aren't twin stud cellulose). Aiming for high airtightness, insulation levels and convenience (e.g a subcontracted package) was leading me towards a TF from one of the usual suspects. But would consider ICF if it ends up being a better compromise. For noise, where do we would think ICF ends up compared to the twin stud cellulose?

My site is about 50m from a railway line, so external noise is a consideration when deciding on timber frame spec. For all options the aim is for high airtightness, triple glazing and assumes fibre cement external cladding (or similar) As I see it we have these options: 140mm studs (PIR between)plus 25/50mm internal PIR. Cheapest but I assume worst for sound transfer. Same as option 1 but additional sound boarding internally (e.g double plasterboard, acoustic plasterboard). 300mm twin stud filled cellulose. I understand this is best, but more expensive with thicker wall buildup. Other options I haven't thought of? So I have a dilemea, with a trade off between cost/sound insulation and wall thickness. I'm trying to understand if the premium options are worth the additional price. What are people's experience of these options in the real world? Or any other options worth considering?

Following this thread with interest! I'm also thinking about these 'hybrid' heatpumps that support air2water and air2air for my selfbuild. I can't directly help with your questions, but also notice Daikin released a similar offering in June: https://www.daikin.eu/en_us/press-releases/daikin-introduces-x-series.html Is it confirmed that Samsung EHS Quint will be BUS grant eligible?

Slope is about 1 in 6 Appreciate everyone's comments. We're definitely striving for simplicity - doing more earthworks and building a beam&block platform to sit a TF on top definitely sounds appealing. We'll investigate!

Thanks for the Welcome! Potentially both Timberframe and ICF. The plot is sloping, so needs a lower ground floor which dug into the hilside and partially below ground level. Working assumption at the moment is a raft foundation, tanked ICF lower ground floor then timber frame 1st/2nd floor. Definitely would be interested to hear if anyone on the forum has experience of this, given it's less common.

Hi everyone - I'm Tim Newbie selfbuilder here, in the early stages of planning our self-build project in South Wales (But currently living in Bristol). Looking to build a family home to passive house principles, and avoid any Grand-designs style crises during the process! Excited to be part of this forum, which is a great source of info! I look forward to picking your collective brain more as we make our design choices and progress with the project.